Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
Kit" which formed the basis of the original Getting Started chapter
- in this book. Bob was one of our first customers for a production
+ in this manual. Bob was one of our first customers for a production
TeleMetrum, and his continued enthusiasm and contributions
are immensely gratifying and highly appreciated!
</para>
<para>
The newest device is TeleMini, a dual deploy altimeter with
radio telemetry and radio direction finding. This device is only
- 13mm by 38mm (½ inch by 1½ inches) and can fit easily in an 18mm air-frame.
+ 13mm by 38mm (½ inch by 1½ inches) and can fit easily in an 18mm
+ air-frame.
</para>
<para>
Complementing TeleMetrum and TeleMini is TeleDongle, a USB to RF
<para>
All Altus Metrum products are sophisticated electronic devices.
When handled gently and properly installed in an air-frame, they
- will deliver impressive results. However, like all electronic
+ will deliver impressive results. However, as with all electronic
devices, there are some precautions you must take.
</para>
<para>
</para>
<para>
In flight or "pad" mode, the altimeter engages the flight
- state machine, goes into transmit-only mode on the RF link
- sending telemetry, and waits for launch to be detected.
+ state machine, goes into transmit-only mode to
+ send telemetry, and waits for launch to be detected.
Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
on the beeper or lights, followed by beeps or flashes
indicating the state of the pyrotechnic igniter continuity.
If idle mode is entered, you will hear an audible "di-dit" or see
two short flashes ("I" for idle), and the flight state machine is
disengaged, thus no ejection charges will fire. The altimeters also
- listen on the RF link when in idle mode for requests sent via
+ listen for the radio link when in idle mode for requests sent via
TeleDongle. Commands can be issued to a TeleMetrum in idle mode
over either
- USB or the RF link equivalently. TeleMini only has the RF link.
+ USB or the radio link equivalently. TeleMini only has the radio link.
Idle mode is useful for configuring the altimeter, for extracting data
from the on-board storage chip after flight, and for ground testing
pyro charges.
very large air-frames, is that you can power the board up while the
rocket is horizontal, such that it comes up in idle mode. Then you can
raise the air-frame to launch position, and issue a 'reset' command
- via TeleDongle over the RF link to cause the altimeter to reboot and
+ via TeleDongle over the radio link to cause the altimeter to reboot and
come up in flight mode. This is much safer than standing on the top
step of a rickety step-ladder or hanging off the side of a launch
tower with a screw-driver trying to turn on your avionics before
complete.
</para>
</section>
+ <section>
+ <title>Controlling An Altimeter Over The Radio Link</title>
+ <para>
+ One of the unique features of the Altus Metrum system is
+ the ability to create a two way command link between TeleDongle
+ and an altimeter using the digital radio transceivers built into
+ each device. This allows you to interact with the altimeter from
+ afar, as if it were directly connected to the computer.
+ </para>
+ <para>
+ Any operation which can be performed with TeleMetrum can
+ either be done with TeleMetrum directly connected to the
+ computer via the USB cable, or through the radio
+ link. TeleMini doesn't provide a USB connector and so it is
+ always communicated with over radio. Select the appropriate
+ TeleDongle device when the list of devices is presented and
+ AltosUI will interact with an altimeter over the radio link.
+ </para>
+ <para>
+ One oddity in the current interface is how AltosUI selects the
+ frequency for radio communications. Instead of providing
+ an interface to specifically configure the frequency, it uses
+ whatever frequency was most recently selected for the target
+ TeleDongle device in Monitor Flight mode. If you haven't ever
+ used that mode with the TeleDongle in question, select the
+ Monitor Flight button from the top level UI, and pick the
+ appropriate TeleDongle device. Once the flight monitoring
+ window is open, select the desired frequency and then close it
+ down again. All radio communications will now use that frequency.
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Save Flight Data—Recover flight data from the rocket without
+ opening it up.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Configure altimeter apogee delays or main deploy heights
+ to respond to changing launch conditions. You can also
+ 'reboot' the altimeter. Use this to remotely enable the
+ flight computer by turning TeleMetrum on in "idle" mode,
+ then once the air-frame is oriented for launch, you can
+ reboot the altimeter and have it restart in pad mode
+ without having to climb the scary ladder.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Fire Igniters—Test your deployment charges without snaking
+ wires out through holes in the air-frame. Simply assembly the
+ rocket as if for flight with the apogee and main charges
+ loaded, then remotely command the altimeter to fire the
+ igniters.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ Operation over the radio link for configuring an altimeter, ground
+ testing igniters, and so forth uses the same RF frequencies as flight
+ telemetry. To configure the desired TeleDongle frequency, select
+ the monitor flight tab, then use the frequency selector and
+ close the window before performing other desired radio operations.
+ </para>
+ <para>
+ TeleMetrum only enables radio commanding in 'idle' mode, so
+ make sure you have TeleMetrum lying horizontally when you turn
+ it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
+ flight, and will not be listening for command packets from TeleDongle.
+ </para>
+ <para>
+ TeleMini listens for a command packet for five seconds after
+ first being turned on, if it doesn't hear anything, it enters
+ 'pad' mode, ready for flight and will no longer listen for
+ command packets. The easiest way to connect to TeleMini is to
+ initiate the command and select the TeleDongle device. At this
+ point, the TeleDongle will be attempting to communicate with
+ the TeleMini. Now turn TeleMini on, and it should immediately
+ start communicating with the TeleDongle and the desired
+ operation can be performed.
+ </para>
+ <para>
+ You can monitor the operation of the radio link by watching the
+ lights on the devices. The red LED will flash each time a packet
+ is tramsitted, while the green LED will light up on TeleDongle when
+ it is waiting to receive a packet from the altimeter.
+ </para>
+ </section>
<section>
<title>Ground Testing </title>
<para>
An important aspect of preparing a rocket using electronic deployment
for flight is ground testing the recovery system. Thanks
- to the bi-directional RF link central to the Altus Metrum system,
+ to the bi-directional radio link central to the Altus Metrum system,
this can be accomplished in a TeleMetrum or TeleMini equipped rocket
with less work than you may be accustomed to with other systems. It
can even be fun!
link.
</para>
<para>
- By design, the altimeter firmware listens for an RF connection when
+ By design, the altimeter firmware listens for the radio link when
it's in "idle mode", which
- allows us to use the RF link to configure the rocket, do things like
+ allows us to use the radio link to configure the rocket, do things like
ejection tests, and extract data after a flight without having to
crack open the air-frame. However, when the board is in "flight
mode", the altimeter only
transmits and doesn't listen at all. That's because we want to put
ultimate priority on event detection and getting telemetry out of
- the rocket and out over
- the RF link in case the rocket crashes and we aren't able to extract
+ the rocket through
+ the radio in case the rocket crashes and we aren't able to extract
data later...
</para>
<para>
Gaussian filter before they go into the modulator to limit the
transmitted bandwidth. When combined with the hardware forward error
correction support in the cc1111 chip, this allows us to have a very
- robust 38.4 kilobit data link with only 10 milliwatts of transmit
- power, a whip antenna in the rocket, and a hand-held Yagi on the
- ground. We've had flights to above 21k feet AGL with great reception,
- and calculations suggest we should be good to well over 40k feet AGL
- with a 5-element yagi on the ground. We hope to fly boards to higher
- altitudes over time, and would of course appreciate customer feedback
- on performance in higher altitude flights!
- </para>
- </section>
- <section>
- <title>Configurable Parameters</title>
- <para>
- Configuring an Altus Metrum altimeter for flight is very
- simple. Even on our baro-only TeleMini board, the use of a Kalman
- filter means there is no need to set a "mach delay". The few
- configurable parameters can all be set using AltosUI over USB or
- or RF link via TeleDongle.
- </para>
- <section>
- <title>Radio Frequencies</title>
- <para>
- The Altus Metrum boards support frequencies in the 70cm
- band. By default, the configuration interface provides a
- list of 10 common frequencies in 100kHz channels starting at
- 434.550MHz. However, the firmware supports use of
- any 50kHz multiple within the 70cm band. At any given
- launch, we highly recommend coordinating who will use each
- frequency and when to avoid interference. And of course, both
- altimeter and TeleDongle must be configured to the same
- frequency to successfully communicate with each other.
- </para>
- <para>
- To set the radio frequency, use the 'c R' command to specify the
- radio transceiver configuration parameter. This parameter is computed
- using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
- the standard calibration reference frequency, 'S', (normally 434.550MHz):
- <programlisting>
- R = F / S * C
- </programlisting>
- Round the result to the nearest integer value.
- As with all 'c' sub-commands, follow this with a 'c w' to write the
- change to the parameter block in the on-board flash on
- your altimeter board if you want the change to stay in place across reboots.
- </para>
- </section>
- <section>
- <title>Apogee Delay</title>
- <para>
- Apogee delay is the number of seconds after the altimeter detects flight
- apogee that the drogue charge should be fired. In most cases, this
- should be left at the default of 0. However, if you are flying
- redundant electronics such as for an L3 certification, you may wish
- to set one of your altimeters to a positive delay so that both
- primary and backup pyrotechnic charges do not fire simultaneously.
- </para>
- <para>
- To set the apogee delay, use the 'c d' command.
- As with all 'c' sub-commands, follow this with a 'c w' to write the
- change to the parameter block in the on-board DataFlash chip.
- </para>
- <para>
- Please note that the Altus Metrum apogee detection algorithm
- fires exactly at apogee. If you are also flying an
- altimeter like the PerfectFlite MAWD, which only supports
- selecting 0 or 1 seconds of apogee delay, you may wish to
- set the MAWD to 0 seconds delay and set the TeleMetrum to
- fire your backup 2 or 3 seconds later to avoid any chance of
- both charges firing simultaneously. We've flown several
- air-frames this way quite happily, including Keith's
- successful L3 cert.
- </para>
- </section>
- <section>
- <title>Main Deployment Altitude</title>
- <para>
- By default, the altimeter will fire the main deployment charge at an
- elevation of 250 meters (about 820 feet) above ground. We think this
- is a good elevation for most air-frames, but feel free to change this
- to suit. In particular, if you are flying two altimeters, you may
- wish to set the
- deployment elevation for the backup altimeter to be something lower
- than the primary so that both pyrotechnic charges don't fire
- simultaneously.
- </para>
- <para>
- To set the main deployment altitude, use the 'c m' command.
- As with all 'c' sub-commands, follow this with a 'c w' to write the
- change to the parameter block in the on-board DataFlash chip.
- </para>
- </section>
- </section>
- <section>
- <title>Calibration</title>
- <para>
- There are only two calibrations required for a TeleMetrum board, and
- only one for TeleDongle and TeleMini.
- </para>
- <section>
- <title>Radio Frequency</title>
- <para>
- The radio frequency is synthesized from a clock based on the 48 MHz
- crystal on the board. The actual frequency of this oscillator must be
- measured to generate a calibration constant. While our GFSK modulation
- bandwidth is wide enough to allow boards to communicate even when
- their oscillators are not on exactly the same frequency, performance
- is best when they are closely matched.
- Radio frequency calibration requires a calibrated frequency counter.
- Fortunately, once set, the variation in frequency due to aging and
- temperature changes is small enough that re-calibration by customers
- should generally not be required.
- </para>
- <para>
- To calibrate the radio frequency, connect the UHF antenna port to a
- frequency counter, set the board to 434.550MHz, and use the 'C'
- command to generate a CW carrier. Wait for the transmitter temperature
- to stabilize and the frequency to settle down.
- Then, divide 434.550 MHz by the
- measured frequency and multiply by the current radio cal value show
- in the 'c s' command. For an unprogrammed board, the default value
- is 1186611. Take the resulting integer and program it using the 'c f'
- command. Testing with the 'C' command again should show a carrier
- within a few tens of Hertz of the intended frequency.
- As with all 'c' sub-commands, follow this with a 'c w' to write the
- change to the parameter block in the on-board DataFlash chip.
- </para>
- <para>
- when the radio calibration value is changed, the radio
- frequency value is reset to the same value, so you'll need
- to recompute and reset the radio frequency value using the
- new radio calibration value.
- </para>
- </section>
- <section>
- <title>TeleMetrum Accelerometer</title>
- <para>
- The TeleMetrum accelerometer we use has its own 5 volt power supply and
- the output must be passed through a resistive voltage divider to match
- the input of our 3.3 volt ADC. This means that unlike the barometric
- sensor, the output of the acceleration sensor is not ratio-metric to
- the ADC converter, and calibration is required. We also support the
- use of any of several accelerometers from a Freescale family that
- includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity,
- a simple 2-point calibration yields acceptable results capturing both
- the different sensitivities and ranges of the different accelerometer
- parts and any variation in power supply voltages or resistor values
- in the divider network.
- </para>
- <para>
- To calibrate the acceleration sensor, use the 'c a 0' command. You
- will be prompted to orient the board vertically with the UHF antenna
- up and press a key, then to orient the board vertically with the
- UHF antenna down and press a key.
- As with all 'c' sub-commands, follow this with a 'c w' to write the
- change to the parameter block in the on-board DataFlash chip.
- </para>
- <para>
- The +1g and -1g calibration points are included in each telemetry
- frame and are part of the header extracted by ao-dumplog after flight.
- Note that we always store and return raw ADC samples for each
- sensor... nothing is permanently "lost" or "damaged" if the
- calibration is poor.
- </para>
- <para>
- In the unlikely event an accel cal that goes badly, it is possible
- that TeleMetrum may always come up in 'pad mode' and as such not be
- listening to either the USB or radio interfaces. If that happens,
- there is a special hook in the firmware to force the board back
- in to 'idle mode' so you can re-do the cal. To use this hook, you
- just need to ground the SPI clock pin at power-on. This pin is
- available as pin 2 on the 8-pin companion connector, and pin 1 is
- ground. So either carefully install a fine-gauge wire jumper
- between the two pins closest to the index hole end of the 8-pin
- connector, or plug in the programming cable to the 8-pin connector
- and use a small screwdriver or similar to short the two pins closest
- to the index post on the 4-pin end of the programming cable, and
- power up the board. It should come up in 'idle mode' (two beeps).
- </para>
- </section>
- </section>
- <section>
- <title>Updating Device Firmware</title>
- <para>
- The big conceptual thing to realize is that you have to use a
- TeleDongle as a programmer to update a TeleMetrum or TeleMini,
- and a TeleMetrum or other TeleDongle to program the TeleDongle
- Due to limited memory resources in the cc1111, we don't support
- programming directly over USB.
- </para>
- <para>
- You may wish to begin by ensuring you have current firmware images.
- These are distributed as part of the AltOS software bundle that
- also includes the AltosUI ground station program. Newer ground
- station versions typically work fine with older firmware versions,
- so you don't need to update your devices just to try out new
- software features. You can always download the most recent
- version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
- </para>
- <para>
- We recommend updating the altimeter first, before updating TeleDongle.
- </para>
- <section>
- <title>Updating TeleMetrum Firmware</title>
- <orderedlist inheritnum='inherit' numeration='arabic'>
- <listitem>
- Find the 'programming cable' that you got as part of the starter
- kit, that has a red 8-pin MicroMaTch connector on one end and a
- red 4-pin MicroMaTch connector on the other end.
- </listitem>
- <listitem>
- Take the 2 screws out of the TeleDongle case to get access
- to the circuit board.
- </listitem>
- <listitem>
- Plug the 8-pin end of the programming cable to the
- matching connector on the TeleDongle, and the 4-pin end to the
- matching connector on the TeleMetrum.
- Note that each MicroMaTch connector has an alignment pin that
- goes through a hole in the PC board when you have the cable
- oriented correctly.
- </listitem>
- <listitem>
- Attach a battery to the TeleMetrum board.
- </listitem>
- <listitem>
- Plug the TeleDongle into your computer's USB port, and power
- up the TeleMetrum.
- </listitem>
- <listitem>
- Run AltosUI, and select 'Flash Image' from the File menu.
- </listitem>
- <listitem>
- Pick the TeleDongle device from the list, identifying it as the
- programming device.
- </listitem>
- <listitem>
- Select the image you want put on the TeleMetrum, which should have a
- name in the form telemetrum-v1.1-1.0.0.ihx. It should be visible
- in the default directory, if not you may have to poke around
- your system to find it.
- </listitem>
- <listitem>
- Make sure the configuration parameters are reasonable
- looking. If the serial number and/or RF configuration
- values aren't right, you'll need to change them.
- </listitem>
- <listitem>
- Hit the 'OK' button and the software should proceed to flash
- the TeleMetrum with new firmware, showing a progress bar.
- </listitem>
- <listitem>
- Confirm that the TeleMetrum board seems to have updated OK, which you
- can do by plugging in to it over USB and using a terminal program
- to connect to the board and issue the 'v' command to check
- the version, etc.
- </listitem>
- <listitem>
- If something goes wrong, give it another try.
- </listitem>
- </orderedlist>
- </section>
- <section>
- <title>Updating TeleMini Firmware</title>
- <orderedlist inheritnum='inherit' numeration='arabic'>
- <listitem>
- You'll need a special 'programming cable' to reprogram the
- TeleMini. It's available on the Altus Metrum web store, or
- you can make your own using an 8-pin MicroMaTch connector on
- one end and a set of four pins on the other.
- </listitem>
- <listitem>
- Take the 2 screws out of the TeleDongle case to get access
- to the circuit board.
- </listitem>
- <listitem>
- Plug the 8-pin end of the programming cable to the matching
- connector on the TeleDongle, and the 4-pins into the holes
- in the TeleMini circuit board. Note that the MicroMaTch
- connector has an alignment pin that goes through a hole in
- the PC board when you have the cable oriented correctly, and
- that pin 1 on the TeleMini board is marked with a square pad
- while the other pins have round pads.
- </listitem>
- <listitem>
- Attach a battery to the TeleMini board.
- </listitem>
- <listitem>
- Plug the TeleDongle into your computer's USB port, and power
- up the TeleMini
- </listitem>
- <listitem>
- Run AltosUI, and select 'Flash Image' from the File menu.
- </listitem>
- <listitem>
- Pick the TeleDongle device from the list, identifying it as the
- programming device.
- </listitem>
- <listitem>
- Select the image you want put on the TeleMini, which should have a
- name in the form telemini-v1.0-1.0.0.ihx. It should be visible
- in the default directory, if not you may have to poke around
- your system to find it.
- </listitem>
- <listitem>
- Make sure the configuration parameters are reasonable
- looking. If the serial number and/or RF configuration
- values aren't right, you'll need to change them.
- </listitem>
- <listitem>
- Hit the 'OK' button and the software should proceed to flash
- the TeleMini with new firmware, showing a progress bar.
- </listitem>
- <listitem>
- Confirm that the TeleMini board seems to have updated OK, which you
- can do by configuring it over the RF link through the TeleDongle, or
- letting it come up in "flight" mode and listening for telemetry.
- </listitem>
- <listitem>
- If something goes wrong, give it another try.
- </listitem>
- </orderedlist>
- </section>
- <section>
- <title>Updating TeleDongle Firmware</title>
- <para>
- Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
- firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
- </para>
- <orderedlist inheritnum='inherit' numeration='arabic'>
- <listitem>
- Find the 'programming cable' that you got as part of the starter
- kit, that has a red 8-pin MicroMaTch connector on one end and a
- red 4-pin MicroMaTch connector on the other end.
- </listitem>
- <listitem>
- Find the USB cable that you got as part of the starter kit, and
- plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
- </listitem>
- <listitem>
- Take the 2 screws out of the TeleDongle case to get access
- to the circuit board.
- </listitem>
- <listitem>
- Plug the 8-pin end of the programming cable to the
- matching connector on the programmer, and the 4-pin end to the
- matching connector on the TeleDongle.
- Note that each MicroMaTch connector has an alignment pin that
- goes through a hole in the PC board when you have the cable
- oriented correctly.
- </listitem>
- <listitem>
- Attach a battery to the TeleMetrum board if you're using one.
- </listitem>
- <listitem>
- Plug both the programmer and the TeleDongle into your computer's USB
- ports, and power up the programmer.
- </listitem>
- <listitem>
- Run AltosUI, and select 'Flash Image' from the File menu.
- </listitem>
- <listitem>
- Pick the programmer device from the list, identifying it as the
- programming device.
- </listitem>
- <listitem>
- Select the image you want put on the TeleDongle, which should have a
- name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
- in the default directory, if not you may have to poke around
- your system to find it.
- </listitem>
- <listitem>
- Make sure the configuration parameters are reasonable
- looking. If the serial number and/or RF configuration
- values aren't right, you'll need to change them. The TeleDongle
- serial number is on the "bottom" of the circuit board, and can
- usually be read through the translucent blue plastic case without
- needing to remove the board from the case.
- </listitem>
- <listitem>
- Hit the 'OK' button and the software should proceed to flash
- the TeleDongle with new firmware, showing a progress bar.
- </listitem>
- <listitem>
- Confirm that the TeleDongle board seems to have updated OK, which you
- can do by plugging in to it over USB and using a terminal program
- to connect to the board and issue the 'v' command to check
- the version, etc. Once you're happy, remove the programming cable
- and put the cover back on the TeleDongle.
- </listitem>
- <listitem>
- If something goes wrong, give it another try.
- </listitem>
- </orderedlist>
+ robust 38.4 kilobit data link with only 10 milliwatts of transmit
+ power, a whip antenna in the rocket, and a hand-held Yagi on the
+ ground. We've had flights to above 21k feet AGL with great reception,
+ and calculations suggest we should be good to well over 40k feet AGL
+ with a 5-element yagi on the ground. We hope to fly boards to higher
+ altitudes over time, and would of course appreciate customer feedback
+ on performance in higher altitude flights!
+ </para>
+ </section>
+ <section>
+ <title>Configurable Parameters</title>
<para>
- Be careful removing the programming cable from the locking 8-pin
- connector on TeleMetrum. You'll need a fingernail or perhaps a thin
- screwdriver or knife blade to gently pry the locking ears out
- slightly to extract the connector. We used a locking connector on
- TeleMetrum to help ensure that the cabling to companion boards
- used in a rocket don't ever come loose accidentally in flight.
+ Configuring an Altus Metrum altimeter for flight is very
+ simple. Even on our baro-only TeleMini board, the use of a Kalman
+ filter means there is no need to set a "mach delay". The few
+ configurable parameters can all be set using AltosUI over USB or
+ or radio link via TeleDongle.
</para>
+ <section>
+ <title>Radio Frequency</title>
+ <para>
+ Altus Metrum boards support radio frequencies in the 70cm
+ band. By default, the configuration interface provides a
+ list of 10 "standard" frequencies in 100kHz channels starting at
+ 434.550MHz. However, the firmware supports use of
+ any 50kHz multiple within the 70cm band. At any given
+ launch, we highly recommend coordinating when and by whom each
+ frequency will be used to avoid interference. And of course, both
+ altimeter and TeleDongle must be configured to the same
+ frequency to successfully communicate with each other.
+ </para>
+ </section>
+ <section>
+ <title>Apogee Delay</title>
+ <para>
+ Apogee delay is the number of seconds after the altimeter detects flight
+ apogee that the drogue charge should be fired. In most cases, this
+ should be left at the default of 0. However, if you are flying
+ redundant electronics such as for an L3 certification, you may wish
+ to set one of your altimeters to a positive delay so that both
+ primary and backup pyrotechnic charges do not fire simultaneously.
+ </para>
+ <para>
+ The Altus Metrum apogee detection algorithm fires exactly at
+ apogee. If you are also flying an altimeter like the
+ PerfectFlite MAWD, which only supports selecting 0 or 1
+ seconds of apogee delay, you may wish to set the MAWD to 0
+ seconds delay and set the TeleMetrum to fire your backup 2
+ or 3 seconds later to avoid any chance of both charges
+ firing simultaneously. We've flown several air-frames this
+ way quite happily, including Keith's successful L3 cert.
+ </para>
+ </section>
+ <section>
+ <title>Main Deployment Altitude</title>
+ <para>
+ By default, the altimeter will fire the main deployment charge at an
+ elevation of 250 meters (about 820 feet) above ground. We think this
+ is a good elevation for most air-frames, but feel free to change this
+ to suit. In particular, if you are flying two altimeters, you may
+ wish to set the
+ deployment elevation for the backup altimeter to be something lower
+ than the primary so that both pyrotechnic charges don't fire
+ simultaneously.
+ </para>
+ </section>
+ <section>
+ <title>Maximum Flight Log</title>
+ <para>
+ TeleMetrum version 1.1 has 2MB of on-board flash storage,
+ enough to hold over 40 minutes of data at full data rate
+ (100 samples/second). TeleMetrum 1.0 has 1MB of on-board
+ storage. As data are stored at a reduced rate during descent
+ (10 samples/second), there's plenty of space to store many
+ flights worth of data.
+ </para>
+ <para>
+ The on-board flash is partitioned into separate flight logs,
+ each of a fixed maximum size. Increase the maximum size of
+ each log and you reduce the number of flights that can be
+ stored. Decrease the size and TeleMetrum can store more
+ flights.
+ </para>
+ <para>
+ All of the configuration data is also stored in the flash
+ memory, which consumes 64kB on TeleMetrum v1.1 and 256B on
+ TeleMetrum v1.0. This configuration space is not available
+ for storing flight log data.
+ </para>
+ <para>
+ To compute the amount of space needed for a single flight,
+ you can multiply the expected ascent time (in seconds) by
+ 800, multiply the expected descent time (in seconds) by 80
+ and add the two together. That will slightly under-estimate
+ the storage (in bytes) needed for the flight. For instance,
+ a flight spending 20 seconds in ascent and 150 seconds in
+ descent will take about (20 * 800) + (150 * 80) = 28000
+ bytes of storage. You could store dozens of these flights in
+ the on-board flash.
+ </para>
+ <para>
+ The default size, 192kB, allows for 10 flights of storage on
+ TeleMetrum v1.1 and 5 flights on TeleMetrum v1.0. This
+ ensures that you won't need to erase the memory before
+ flying each time while still allowing more than sufficient
+ storage for each flight.
+ </para>
+ <para>
+ As TeleMini does not contain an accelerometer, it stores
+ data at 10 samples per second during ascent and one sample
+ per second during descent. Each sample is a two byte reading
+ from the barometer. These are stored in 5kB of
+ on-chip flash memory which can hold 256 seconds at the
+ ascent rate or 2560 seconds at the descent rate. Because of
+ the limited storage, TeleMini cannot hold data for more than
+ one flight, and so must be erased after each flight or it
+ will not capture data for subsequent flights.
+ </para>
+ </section>
+ <section>
+ <title>Ignite Mode</title>
+ <para>
+ Instead of firing one charge at apogee and another charge at
+ a fixed height above the ground, you can configure the
+ altimeter to fire both at apogee or both during
+ descent. This was added to support an airframe that has two
+ TeleMetrum computers, one in the fin can and one in the
+ nose.
+ </para>
+ <para>
+ Providing the ability to use both igniters for apogee or
+ main allows some level of redundancy without needing two
+ flight computers. In Redundant Apogee or Redundant Main
+ mode, the two charges will be fired two seconds apart.
+ </para>
+ </section>
+ <section>
+ <title>Pad Orientation</title>
+ <para>
+ TeleMetrum measures acceleration along the axis of the
+ board. Which way the board is oriented affects the sign of
+ the acceleration value. Instead of trying to guess which way
+ the board is mounted in the air frame, TeleMetrum must be
+ explicitly configured for either Antenna Up or Antenna
+ Down. The default, Antenna Up, expects the end of the
+ TeleMetrum board connected to the 70cm antenna to be nearest
+ the nose of the rocket, with the end containing the screw
+ terminals nearest the tail.
+ </para>
+ </section>
</section>
- </section>
</chapter>
<chapter>
you know how strong a signal TeleDongle is receiving. The
radio inside TeleDongle operates down to about -99dBm;
weaker signals may not be receivable. The packet link uses
- error correction and detection techniques which prevent
+ error detection and correction techniques which prevent
incorrect data from being reported.
</para>
</listitem>
They're arranged in 'flight order' so that as the flight
progresses, the selected tab automatically switches to display
data relevant to the current state of the flight. You can select
- other tabs at any time. The final 'table' tab contains all of
- the telemetry data in one place.
+ other tabs at any time. The final 'table' tab displays all of
+ the raw telemetry values in one place in a spreadsheet-like format.
</para>
<section>
<title>Launch Pad</title>
<para>
To monitor whether the apogee charge operated correctly, the
current descent rate is reported along with the current
- height. Good descent rates generally range from 15-30m/s.
+ height. Good descent rates vary based on the choice of recovery
+ components, but generally range from 15-30m/s on drogue and should
+ be below 10m/s when under the main parachute in a dual-deploy flight.
</para>
<para>
For TeleMetrum altimeters, you can locate the rocket in the sky
<para>
Finally, the igniter voltages are reported in this tab as
well, both to monitor the main charge as well as to see what
- the status of the apogee charge is.
+ the status of the apogee charge is. Note that some commercial
+ e-matches are designed to retain continuity even after being
+ fired, and will continue to show as green or return from red to
+ green after firing.
</para>
</section>
<section>
<title>Landed</title>
<para>
Once the rocket is on the ground, attention switches to
- recovery. While the radio signal is generally lost once the
+ recovery. While the radio signal is often lost once the
rocket is on the ground, the last reported GPS position is
generally within a short distance of the actual landing location.
</para>
The last reported GPS position is reported both by
latitude and longitude as well as a bearing and distance from
the launch pad. The distance should give you a good idea of
- whether you'll want to walk or hitch a ride. Take the reported
+ whether to walk or hitch a ride. Take the reported
latitude and longitude and enter them into your hand-held GPS
unit and have that compute a track to the landing location.
</para>
<para>
Both TeleMini and TeleMetrum will continue to transmit RDF
tones after landing, allowing you to locate the rocket by
- following the radio signal. You may need to get away from
- the clutter of the flight line, or even get up on a hill (or
- your neighbor's RV) to receive the RDF signal.
+ following the radio signal if necessary. You may need to get
+ away from the clutter of the flight line, or even get up on
+ a hill (or your neighbor's RV roof) to receive the RDF signal.
</para>
<para>
The maximum height, speed and acceleration reported
during the flight are displayed for your admiring observers.
+ The accuracy of these immediate values depends on the quality
+ of your radio link and how many packets were received.
+ Recovering the on-board data after flight will likely yield
+ more precise results.
</para>
<para>
To get more detailed information about the flight, you can
<section>
<title>Site Map</title>
<para>
- When the TeleMetrum gets a GPS fix, the Site Map tab will map
+ When the TeleMetrum has a GPS fix, the Site Map tab will map
the rocket's position to make it easier for you to locate the
rocket, both while it is in the air, and when it has landed. The
rocket's state is indicated by color: white for pad, red for
</para>
<para>
Images are fetched automatically via the Google Maps Static API,
- and are cached for reuse. If map images cannot be downloaded,
+ and cached on disk for reuse. If map images cannot be downloaded,
the rocket's path will be traced on a dark gray background
instead.
</para>
</para>
</section>
</section>
- <section>
- <title>Packet Command Mode</title>
- <subtitle>Controlling An Altimeter Over The Radio Link</subtitle>
- <para>
- One of the unique features of the Altus Metrum environment is
- the ability to create a two way command link between TeleDongle
- and an altimeter using the digital radio transceivers built into
- each device. This allows you to interact with the altimeter from
- afar, as if it were directly connected to the computer.
- </para>
- <para>
- Any operation which can be performed with TeleMetrum
- can either be done with TeleMetrum directly connected to
- the computer via the USB cable, or through the packet
- link. Simply select the appropriate TeleDongle device when
- the list of devices is presented and AltosUI will use packet
- command mode.
- </para>
- <para>
- One oddity in the current interface is how AltosUI selects the
- frequency for packet mode communications. Instead of providing
- an interface to specifically configure the frequency, it uses
- whatever frequency was most recently selected for the target
- TeleDongle device in Monitor Flight mode. If you haven't ever
- used that mode with the TeleDongle in question, select the
- Monitor Flight button from the top level UI, pick the
- appropriate TeleDongle device. Once the flight monitoring
- window is open, select the desired frequency and then close it
- down again. All Packet Command Mode operations will now use
- that frequency.
- </para>
- <itemizedlist>
- <listitem>
- <para>
- Save Flight Data—Recover flight data from the rocket without
- opening it up.
- </para>
- </listitem>
- <listitem>
- <para>
- Configure altimeter apogee delays or main deploy heights
- to respond to changing launch conditions. You can also
- 'reboot' the altimeter. Use this to remotely enable the
- flight computer by turning TeleMetrum on in "idle" mode,
- then once the air-frame is oriented for launch, you can
- reboot the altimeter and have it restart in pad mode
- without having to climb the scary ladder.
- </para>
- </listitem>
- <listitem>
- <para>
- Fire Igniters—Test your deployment charges without snaking
- wires out through holes in the air-frame. Simply assembly the
- rocket as if for flight with the apogee and main charges
- loaded, then remotely command the altimeter to fire the
- igniters.
- </para>
- </listitem>
- </itemizedlist>
- <para>
- Packet command mode uses the same RF frequencies as telemetry
- mode. Configure the desired TeleDongle frequency using the
- flight monitor window frequency selector and then close that
- window before performing the desired operation.
- </para>
- <para>
- TeleMetrum only enables packet command mode in 'idle' mode, so
- make sure you have TeleMetrum lying horizontally when you turn
- it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
- flight and will not be listening for command packets from TeleDongle.
- </para>
- <para>
- TeleMini listens for a command packet for five seconds after
- first being turned on, if it doesn't hear anything, it enters
- 'pad' mode, ready for flight and will no longer listen for
- command packets.
- </para>
- <para>
- When packet command mode is enabled, you can monitor the link
- by watching the lights on the
- devices. The red LED will flash each time they
- transmit a packet while the green LED will light up
- on TeleDongle while it is waiting to receive a packet from
- the altimeter.
- </para>
- </section>
<section>
<title>Save Flight Data</title>
<para>
The altimeter records flight data to its internal flash memory.
- The TeleMetrum data is recorded at a much higher rate than the telemetry
+ TeleMetrum data is recorded at a much higher rate than the telemetry
system can handle, and is not subject to radio drop-outs. As
such, it provides a more complete and precise record of the
flight. The 'Save Flight Data' button allows you to read the
connected TeleMetrum and TeleDongle devices. If you select a
TeleMetrum device, the flight data will be downloaded from that
device directly. If you select a TeleDongle device, flight data
- will be downloaded from a TeleMetrum or TeleMini device connected via the
- packet command link to the specified TeleDongle. See the chapter
- on Packet Command Mode for more information about this.
+ will be downloaded from an altimeter over radio link via the
+ specified TeleDongle. See the chapter on Controlling An Altimeter
+ Over The Radio Link for more information.
</para>
<para>
After the device has been selected, a dialog showing the
select which flights to download and which to delete. With
version 0.9 or newer firmware, you must erase flights in order
for the space they consume to be reused by another
- flight. This prevents you from accidentally losing flight data
+ flight. This prevents accidentally losing flight data
if you neglect to download data before flying again. Note that
if there is no more space available in the device, then no
- data will be recorded for a flight.
+ data will be recorded during the next flight.
</para>
<para>
The file name for each flight log is computed automatically
<para>
Once a flight record is selected, a window with two tabs is
opened. The first tab contains a graph with acceleration
- (blue), velocity (green) and altitude (red) of the flight are
- plotted and displayed, measured in metric units. The
+ (blue), velocity (green) and altitude (red) of the flight,
+ measured in metric units. The
apogee(yellow) and main(magenta) igniter voltages are also
displayed; high voltages indicate continuity, low voltages
indicate open circuits. The second tab contains some basic
<para>
Note that telemetry files will generally produce poor graphs
due to the lower sampling rate and missed telemetry packets.
- Use saved flight data for graphing where possible.
+ Use saved flight data in .eeprom files for graphing where possible.
</para>
</section>
<section>
<title>Export Data</title>
<para>
This tool takes the raw data files and makes them available for
- external analysis. When you select this button, you are prompted to select a flight
+ external analysis. When you select this button, you are prompted to
+ select a flight
data file (either .eeprom or .telem will do, remember that
.eeprom files contain higher resolution and more continuous
data). Next, a second dialog appears which is used to select
configuration information from the altimeter, then
there is a single header line which labels all of the
fields. All of these lines start with a '#' character which
- most tools can be configured to skip over.
+ many tools can be configured to skip over.
</para>
<para>
The remaining lines of the file contain the data, with each
<section>
<title>Keyhole Markup Language (for Google Earth)</title>
<para>
- This is the format used by
- Googleearth to provide an overlay within that
- application. With this, you can use Googleearth to see the
- whole flight path in 3D.
+ This is the format used by Google Earth to provide an overlay
+ within that application. With this, you can use Google Earth to
+ see the whole flight path in 3D.
</para>
</section>
</section>
<para>
Select this button and then select either a TeleMetrum or
TeleDongle Device from the list provided. Selecting a TeleDongle
- device will use Packet Command Mode to configure a remote
- altimeter. Learn how to use this in the Packet Command
- Mode chapter.
+ device will use the radio link to configure a remote altimeter.
</para>
<para>
The first few lines of the dialog provide information about the
<para>
Reboot. This reboots the device. Use this to
switch from idle to pad mode by rebooting once the rocket is
- oriented for flight.
+ oriented for flight, or to confirm changes you think you saved
+ are really saved.
</para>
</listitem>
<listitem>
<para>
When flying redundant electronics, it's often important to
ensure that multiple apogee charges don't fire at precisely
- the same time as that can over pressurize the apogee deployment
+ the same time, as that can over pressurize the apogee deployment
bay and cause a structural failure of the air-frame. The Apogee
Delay parameter tells the flight computer to fire the apogee
charge a certain number of seconds after apogee has been
<para>
The radios in every Altus Metrum device are calibrated at the
factory to ensure that they transmit and receive on the
- specified frequency. You can adjust that
- calibration by changing this value. To change the TeleDongle's
- calibration, you must reprogram the unit completely.
+ specified frequency. If you need to you can adjust the calibration
+ by changing this value. Do not do this without understanding what
+ the value means, read the appendix on calibration and/or the source
+ code for more information. To change a TeleDongle's calibration,
+ you must reprogram the unit completely.
</para>
</section>
<section>
size. A smaller value will allow more flights to be stored,
a larger value will record data from longer flights.
</para>
- <para>
- During ascent, TeleMetrum records barometer and
- accelerometer values 100 times per second, other analog
- information (voltages and temperature) 6 times per second
- and GPS data once per second. During descent, the non-GPS
- data is recorded 1/10th as often. Each barometer +
- accelerometer record takes 8 bytes.
- </para>
- <para>
- The default, 192kB, will store over 200 seconds of data at
- the ascent rate, or over 2000 seconds of data at the descent
- rate. That's plenty for most flights. This leaves enough
- storage for five flights in a 1MB system, or 10 flights in a
- 2MB system.
- </para>
- <para>
- The configuration block takes the last available block of
- memory, on v1.0 boards that's just 256 bytes. However, the
- flash part on the v1.1 boards uses 64kB for each block.
- </para>
- <para>
- TeleMini has 5kB of on-board storage, which is plenty for a
- single flight. Make sure you download and delete the data
- before a subsequent flight or it will not log any data.
- </para>
</section>
<section>
<title>Ignite Mode</title>
<section>
<title>Callsign</title>
<para>
- This value is used in command packet mode and is transmitted
- in each packet sent from TeleDongle and received from
- TeleMetrum. It is not used in telemetry mode as that transmits
- packets only from TeleMetrum to TeleDongle. Configure this
+ This value is transmitted in each command packet sent from
+ TeleDongle and received from an altimeter. It is not used in
+ telemetry mode, as the callsign configured in the altimeter board
+ is included in all telemetry packets. Configure this
with the AltosUI operators call sign as needed to comply with
your local radio regulations.
</para>
This reprograms any Altus Metrum device by using a TeleMetrum
or TeleDongle as a programming dongle. Please read the
directions for flashing devices in the Updating Device
- Firmware section above
+ Firmware chapter below.
</para>
<para>
Once you have the programmer and target devices connected,
for Linux which can perform most of the same tasks.
</para>
<para>
- After the flight, you can use the RF link to extract the more detailed data
+ After the flight, you can use the radio link to extract the more detailed data
logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
TeleMetrum board directly. Pulling out the data without having to open up
the rocket is pretty cool! A USB cable is also how you charge the Li-Po
<title>Data Analysis</title>
<para>
Our software makes it easy to log the data from each flight, both the
- telemetry received over the RF link during the flight itself, and the more
+ telemetry received during the flight itself, and the more
complete data log recorded in the flash memory on the altimeter
board. Once this data is on your computer, our post-flight tools make it
easy to quickly get to the numbers everyone wants, like apogee altitude,
<para>
In the future, we intend to offer "companion boards" for the rocket that will
plug in to TeleMetrum to collect additional data, provide more pyro channels,
- and so forth. A reference design for a companion board will be documented
- soon, and will be compatible with open source Arduino programming tools.
+ and so forth.
</para>
<para>
We are also working on the design of a hand-held ground terminal that will
<para>
Any altimeter will generate RFI; the digital circuits use
high-frequency clocks that spray radio interference across a
- wide band. Altusmetrum altimeters generate intentional radio
+ wide band. Altus Metrum altimeters generate intentional radio
signals as well, increasing the amount of RF energy around the board.
</para>
<para>
<para>
Voltages are induced when radio frequency energy is
transmitted from one circuit to another. Here are things that
- increase the induced voltage and current:
+ influence the induced voltage and current:
</para>
<itemizedlist>
<listitem>
To accurately measure atmospheric pressure, the ebay
containing the altimeter must be vented outside the
air-frame. The vent must be placed in a region of linear
- airflow, smooth and not in an area of increasing or decreasing
- pressure.
+ airflow, have smooth edges, and away from areas of increasing or
+ decreasing pressure.
</para>
<para>
The barometric sensor in the altimeter is quite sensitive to
</para>
</section>
<section>
- <title>Ground Testing</title>
- <para>
- The most important aspect of any installation is careful
- ground testing. Bringing an air-frame up to the LCO table which
- hasn't been ground tested can lead to delays or ejection
- charges firing on the pad, or, even worse, a recovery system
- failure.
- </para>
+ <title>Ground Testing</title>
+ <para>
+ The most important aspect of any installation is careful
+ ground testing. Bringing an air-frame up to the LCO table which
+ hasn't been ground tested can lead to delays or ejection
+ charges firing on the pad, or, even worse, a recovery system
+ failure.
+ </para>
+ <para>
+ Do a 'full systems' test that includes wiring up all igniters
+ without any BP and turning on all of the electronics in flight
+ mode. This will catch any mistakes in wiring and any residual
+ RFI issues that might accidentally fire igniters at the wrong
+ time. Let the air-frame sit for several minutes, checking for
+ adequate telemetry signal strength and GPS lock. If any igniters
+ fire unexpectedly, find and resolve the issue before loading any
+ BP charges!
+ </para>
+ <para>
+ Ground test the ejection charges. Prepare the rocket for
+ flight, loading ejection charges and igniters. Completely
+ assemble the air-frame and then use the 'Fire Igniters'
+ interface through a TeleDongle to command each charge to
+ fire. Make sure the charge is sufficient to robustly separate
+ the air-frame and deploy the recovery system.
+ </para>
+ </section>
+ </chapter>
+ <chapter>
+ <title>Updating Device Firmware</title>
+ <para>
+ The big concept to understand is that you have to use a
+ TeleDongle as a programmer to update a TeleMetrum or TeleMini,
+ and a TeleMetrum or other TeleDongle to program the TeleDongle
+ Due to limited memory resources in the cc1111, we don't support
+ programming directly over USB.
+ </para>
+ <para>
+ You may wish to begin by ensuring you have current firmware images.
+ These are distributed as part of the AltOS software bundle that
+ also includes the AltosUI ground station program. Newer ground
+ station versions typically work fine with older firmware versions,
+ so you don't need to update your devices just to try out new
+ software features. You can always download the most recent
+ version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
+ </para>
+ <para>
+ We recommend updating the altimeter first, before updating TeleDongle.
+ </para>
+ <section>
+ <title>Updating TeleMetrum Firmware</title>
+ <orderedlist inheritnum='inherit' numeration='arabic'>
+ <listitem>
+ Find the 'programming cable' that you got as part of the starter
+ kit, that has a red 8-pin MicroMaTch connector on one end and a
+ red 4-pin MicroMaTch connector on the other end.
+ </listitem>
+ <listitem>
+ Take the 2 screws out of the TeleDongle case to get access
+ to the circuit board.
+ </listitem>
+ <listitem>
+ Plug the 8-pin end of the programming cable to the
+ matching connector on the TeleDongle, and the 4-pin end to the
+ matching connector on the TeleMetrum.
+ Note that each MicroMaTch connector has an alignment pin that
+ goes through a hole in the PC board when you have the cable
+ oriented correctly.
+ </listitem>
+ <listitem>
+ Attach a battery to the TeleMetrum board.
+ </listitem>
+ <listitem>
+ Plug the TeleDongle into your computer's USB port, and power
+ up the TeleMetrum.
+ </listitem>
+ <listitem>
+ Run AltosUI, and select 'Flash Image' from the File menu.
+ </listitem>
+ <listitem>
+ Pick the TeleDongle device from the list, identifying it as the
+ programming device.
+ </listitem>
+ <listitem>
+ Select the image you want put on the TeleMetrum, which should have a
+ name in the form telemetrum-v1.1-1.0.0.ihx. It should be visible
+ in the default directory, if not you may have to poke around
+ your system to find it.
+ </listitem>
+ <listitem>
+ Make sure the configuration parameters are reasonable
+ looking. If the serial number and/or RF configuration
+ values aren't right, you'll need to change them.
+ </listitem>
+ <listitem>
+ Hit the 'OK' button and the software should proceed to flash
+ the TeleMetrum with new firmware, showing a progress bar.
+ </listitem>
+ <listitem>
+ Confirm that the TeleMetrum board seems to have updated OK, which you
+ can do by plugging in to it over USB and using a terminal program
+ to connect to the board and issue the 'v' command to check
+ the version, etc.
+ </listitem>
+ <listitem>
+ If something goes wrong, give it another try.
+ </listitem>
+ </orderedlist>
+ </section>
+ <section>
+ <title>Updating TeleMini Firmware</title>
+ <orderedlist inheritnum='inherit' numeration='arabic'>
+ <listitem>
+ You'll need a special 'programming cable' to reprogram the
+ TeleMini. It's available on the Altus Metrum web store, or
+ you can make your own using an 8-pin MicroMaTch connector on
+ one end and a set of four pins on the other.
+ </listitem>
+ <listitem>
+ Take the 2 screws out of the TeleDongle case to get access
+ to the circuit board.
+ </listitem>
+ <listitem>
+ Plug the 8-pin end of the programming cable to the matching
+ connector on the TeleDongle, and the 4-pins into the holes
+ in the TeleMini circuit board. Note that the MicroMaTch
+ connector has an alignment pin that goes through a hole in
+ the PC board when you have the cable oriented correctly, and
+ that pin 1 on the TeleMini board is marked with a square pad
+ while the other pins have round pads.
+ </listitem>
+ <listitem>
+ Attach a battery to the TeleMini board.
+ </listitem>
+ <listitem>
+ Plug the TeleDongle into your computer's USB port, and power
+ up the TeleMini
+ </listitem>
+ <listitem>
+ Run AltosUI, and select 'Flash Image' from the File menu.
+ </listitem>
+ <listitem>
+ Pick the TeleDongle device from the list, identifying it as the
+ programming device.
+ </listitem>
+ <listitem>
+ Select the image you want put on the TeleMini, which should have a
+ name in the form telemini-v1.0-1.0.0.ihx. It should be visible
+ in the default directory, if not you may have to poke around
+ your system to find it.
+ </listitem>
+ <listitem>
+ Make sure the configuration parameters are reasonable
+ looking. If the serial number and/or RF configuration
+ values aren't right, you'll need to change them.
+ </listitem>
+ <listitem>
+ Hit the 'OK' button and the software should proceed to flash
+ the TeleMini with new firmware, showing a progress bar.
+ </listitem>
+ <listitem>
+ Confirm that the TeleMini board seems to have updated OK, which you
+ can do by configuring it over the radio link through the TeleDongle, or
+ letting it come up in "flight" mode and listening for telemetry.
+ </listitem>
+ <listitem>
+ If something goes wrong, give it another try.
+ </listitem>
+ </orderedlist>
+ </section>
+ <section>
+ <title>Updating TeleDongle Firmware</title>
<para>
- Do a 'full systems' test that includes wiring up all igniters
- without any BP and turning on all of the electronics in flight
- mode. This will catch any mistakes in wiring and any residual
- RFI issues that might accidentally fire igniters at the wrong
- time. Let the air-frame sit for several minutes, checking for
- adequate telemetry signal strength and GPS lock.
- </para>
+ Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
+ firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
+ </para>
+ <orderedlist inheritnum='inherit' numeration='arabic'>
+ <listitem>
+ Find the 'programming cable' that you got as part of the starter
+ kit, that has a red 8-pin MicroMaTch connector on one end and a
+ red 4-pin MicroMaTch connector on the other end.
+ </listitem>
+ <listitem>
+ Find the USB cable that you got as part of the starter kit, and
+ plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
+ </listitem>
+ <listitem>
+ Take the 2 screws out of the TeleDongle case to get access
+ to the circuit board.
+ </listitem>
+ <listitem>
+ Plug the 8-pin end of the programming cable to the
+ matching connector on the programmer, and the 4-pin end to the
+ matching connector on the TeleDongle.
+ Note that each MicroMaTch connector has an alignment pin that
+ goes through a hole in the PC board when you have the cable
+ oriented correctly.
+ </listitem>
+ <listitem>
+ Attach a battery to the TeleMetrum board if you're using one.
+ </listitem>
+ <listitem>
+ Plug both the programmer and the TeleDongle into your computer's USB
+ ports, and power up the programmer.
+ </listitem>
+ <listitem>
+ Run AltosUI, and select 'Flash Image' from the File menu.
+ </listitem>
+ <listitem>
+ Pick the programmer device from the list, identifying it as the
+ programming device.
+ </listitem>
+ <listitem>
+ Select the image you want put on the TeleDongle, which should have a
+ name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
+ in the default directory, if not you may have to poke around
+ your system to find it.
+ </listitem>
+ <listitem>
+ Make sure the configuration parameters are reasonable
+ looking. If the serial number and/or RF configuration
+ values aren't right, you'll need to change them. The TeleDongle
+ serial number is on the "bottom" of the circuit board, and can
+ usually be read through the translucent blue plastic case without
+ needing to remove the board from the case.
+ </listitem>
+ <listitem>
+ Hit the 'OK' button and the software should proceed to flash
+ the TeleDongle with new firmware, showing a progress bar.
+ </listitem>
+ <listitem>
+ Confirm that the TeleDongle board seems to have updated OK, which you
+ can do by plugging in to it over USB and using a terminal program
+ to connect to the board and issue the 'v' command to check
+ the version, etc. Once you're happy, remove the programming cable
+ and put the cover back on the TeleDongle.
+ </listitem>
+ <listitem>
+ If something goes wrong, give it another try.
+ </listitem>
+ </orderedlist>
<para>
- Ground test the ejection charges. Prepare the rocket for
- flight, loading ejection charges and igniters. Completely
- assemble the air-frame and then use the 'Fire Igniters'
- interface through a TeleDongle to command each charge to
- fire. Make sure the charge is sufficient to robustly separate
- the air-frame and deploy the recovery system.
+ Be careful removing the programming cable from the locking 8-pin
+ connector on TeleMetrum. You'll need a fingernail or perhaps a thin
+ screwdriver or knife blade to gently pry the locking ears out
+ slightly to extract the connector. We used a locking connector on
+ TeleMetrum to help ensure that the cabling to companion boards
+ used in a rocket don't ever come loose accidentally in flight.
</para>
</section>
</chapter>
but is easily changed using the menus in AltosUI. The files that
are written end in '.telem'. The after-flight
data-dumped files will end in .eeprom and represent continuous data
- unlike the RF-linked .telem files that are subject to losses
+ unlike the .telem files that are subject to losses
along the RF data path.
See the above instructions on what and how to save the eeprom stored
data after physically retrieving your altimeter. Make sure to save
Verify you can connect and disconnect from the units while in your
terminal program by sending the escape-disconnect mentioned above.
</para>
+ <para>
+ To set the radio frequency, use the 'c R' command to specify the
+ radio transceiver configuration parameter. This parameter is computed
+ using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
+ the standard calibration reference frequency, 'S', (normally 434.550MHz):
+ <programlisting>
+ R = F / S * C
+ </programlisting>
+ Round the result to the nearest integer value.
+ As with all 'c' sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board flash on
+ your altimeter board if you want the change to stay in place across reboots.
+ </para>
+ <para>
+ To set the apogee delay, use the 'c d' command.
+ As with all 'c' sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board DataFlash chip.
+ </para>
+ <para>
+ To set the main deployment altitude, use the 'c m' command.
+ As with all 'c' sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board DataFlash chip.
+ </para>
+ <para>
+ To calibrate the radio frequency, connect the UHF antenna port to a
+ frequency counter, set the board to 434.550MHz, and use the 'C'
+ command to generate a CW carrier. Wait for the transmitter temperature
+ to stabilize and the frequency to settle down.
+ Then, divide 434.550 MHz by the
+ measured frequency and multiply by the current radio cal value show
+ in the 'c s' command. For an unprogrammed board, the default value
+ is 1186611. Take the resulting integer and program it using the 'c f'
+ command. Testing with the 'C' command again should show a carrier
+ within a few tens of Hertz of the intended frequency.
+ As with all 'c' sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board DataFlash chip.
+ </para>
<para>
Note that the 'reboot' command, which is very useful on the altimeters,
will likely just cause problems with the dongle. The *correct* way
</para>
<para>
A fun thing to do at the launch site and something you can do while
- learning how to use these units is to play with the RF-link access
+ learning how to use these units is to play with the radio link access
between an altimeter and the TeleDongle. Be aware that you *must* create
some physical separation between the devices, otherwise the link will
not function due to signal overload in the receivers in each device.
</para>
<para>
You can access an altimeter in idle mode from the TeleDongle's USB
- connection using the RF link
+ connection using the radio link
by issuing a 'p' command to the TeleDongle. Practice connecting and
disconnecting ('~~' while using 'cu') from the altimeter. If
you cannot escape out of the "p" command, (by using a '~~' when in
CU) then it is likely that your kernel has issues. Try a newer version.
</para>
<para>
- Using this RF link allows you to configure the altimeter, test
+ Using this radio link allows you to configure the altimeter, test
fire e-matches and igniters from the flight line, check pyro-match
continuity and so forth. You can leave the unit turned on while it
is in 'idle mode' and then place the
strength providing an indication of the direction from receiver to rocket.
</para>
<para>
- TeleMetrum also provides GPS trekking data, which can further simplify
+ TeleMetrum also provides GPS tracking data, which can further simplify
locating the rocket once it has landed. (The last good GPS data
received before touch-down will be on the data screen of 'ao-view'.)
</para>
once you enable the voice output!
</para>
</appendix>
+ <appendix>
+ <title>Calibration</title>
+ <para>
+ There are only two calibrations required for a TeleMetrum board, and
+ only one for TeleDongle and TeleMini. All boards are shipped from
+ the factory pre-calibrated, but the procedures are documented here
+ in case they are ever needed. Re-calibration is not supported by
+ AltosUI, you must connect to the board with a serial terminal program
+ and interact directly with the on-board command interpreter to effect
+ calibration.
+ </para>
+ <section>
+ <title>Radio Frequency</title>
+ <para>
+ The radio frequency is synthesized from a clock based on the 48 MHz
+ crystal on the board. The actual frequency of this oscillator
+ must be measured to generate a calibration constant. While our
+ GFSK modulation
+ bandwidth is wide enough to allow boards to communicate even when
+ their oscillators are not on exactly the same frequency, performance
+ is best when they are closely matched.
+ Radio frequency calibration requires a calibrated frequency counter.
+ Fortunately, once set, the variation in frequency due to aging and
+ temperature changes is small enough that re-calibration by customers
+ should generally not be required.
+ </para>
+ <para>
+ To calibrate the radio frequency, connect the UHF antenna port to a
+ frequency counter, set the board to 434.550MHz, and use the 'C'
+ command in the on-board command interpreter to generate a CW
+ carrier. For TeleMetrum, this is best done over USB. For TeleMini,
+ note that the only way to escape the 'C' command is via power cycle
+ since the board will no longer be listening for commands once it
+ starts generating a CW carrier.
+ </para>
+ <para>
+ Wait for the transmitter temperature to stabilize and the frequency
+ to settle down. Then, divide 434.550 MHz by the
+ measured frequency and multiply by the current radio cal value show
+ in the 'c s' command. For an unprogrammed board, the default value
+ is 1186611. Take the resulting integer and program it using the 'c f'
+ command. Testing with the 'C' command again should show a carrier
+ within a few tens of Hertz of the intended frequency.
+ As with all 'c' sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board DataFlash chip.
+ </para>
+ <para>
+ Note that any time you re-do the radio frequency calibration, the
+ radio frequency is reset to the default 434.550 Mhz. If you want
+ to use another frequency, you will have to set that again after
+ calibration is completed.
+ </para>
+ </section>
+ <section>
+ <title>TeleMetrum Accelerometer</title>
+ <para>
+ The TeleMetrum accelerometer we use has its own 5 volt power
+ supply and
+ the output must be passed through a resistive voltage divider to match
+ the input of our 3.3 volt ADC. This means that unlike the barometric
+ sensor, the output of the acceleration sensor is not ratio-metric to
+ the ADC converter, and calibration is required. Explicitly
+ calibrating the accelerometers also allows us to load any device
+ from a Freescale family that includes at least +/- 40g, 50g, 100g,
+ and 200g parts. Using gravity,
+ a simple 2-point calibration yields acceptable results capturing both
+ the different sensitivities and ranges of the different accelerometer
+ parts and any variation in power supply voltages or resistor values
+ in the divider network.
+ </para>
+ <para>
+ To calibrate the acceleration sensor, use the 'c a 0' command. You
+ will be prompted to orient the board vertically with the UHF antenna
+ up and press a key, then to orient the board vertically with the
+ UHF antenna down and press a key. Note that the accuracy of this
+ calibration depends primarily on how perfectly vertical and still
+ the board is held during the cal process. As with all 'c'
+ sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board DataFlash chip.
+ </para>
+ <para>
+ The +1g and -1g calibration points are included in each telemetry
+ frame and are part of the header stored in onboard flash to be
+ downloaded after flight. We always store and return raw ADC
+ samples for each sensor... so nothing is permanently "lost" or
+ "damaged" if the calibration is poor.
+ </para>
+ <para>
+ In the unlikely event an accel cal goes badly, it is possible
+ that TeleMetrum may always come up in 'pad mode' and as such not be
+ listening to either the USB or radio link. If that happens,
+ there is a special hook in the firmware to force the board back
+ in to 'idle mode' so you can re-do the cal. To use this hook, you
+ just need to ground the SPI clock pin at power-on. This pin is
+ available as pin 2 on the 8-pin companion connector, and pin 1 is
+ ground. So either carefully install a fine-gauge wire jumper
+ between the two pins closest to the index hole end of the 8-pin
+ connector, or plug in the programming cable to the 8-pin connector
+ and use a small screwdriver or similar to short the two pins closest
+ to the index post on the 4-pin end of the programming cable, and
+ power up the board. It should come up in 'idle mode' (two beeps),
+ allowing a re-cal.
+ </para>
+ </section>
+ </appendix>
<appendix
xmlns:xi="http://www.w3.org/2001/XInclude">
<title>Release Notes</title>
projects / fw / altos / blobdiff