<revhistory>
<revision>
<revnumber>1.0</revnumber>
- <date>10 August 2011</date>
+ <date>24 August 2011</date>
<revremark>
Updated for software version 1.0. Note that 1.0 represents a
- telemetry format change, meaning both ends of a link (TeleMetrum/TeleMini and
- TeleDongle) must be updated or communications will fail.
+ telemetry format change, meaning both ends of a link
+ (TeleMetrum/TeleMini and TeleDongle) must be updated or
+ communications will fail.
</revremark>
</revision>
<revision>
<para>
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 has turned into the Getting Started chapter in this
- book. Bob was one of our first customers for a production
- TeleMetrum, and the enthusiasm that led to his contribution of
- this section is immensely gratifying and highy appreciated!
+ Kit" which formed the basis of the original Getting Started chapter
+ 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>
- And thanks to Anthony (AJ) Towns for contributing the
- AltosUI graphing and site map code and documentation. Free
- software means that our customers and friends can become our
+ And thanks to Anthony (AJ) Towns for major contributions including
+ the AltosUI graphing and site map code and associated documentation.
+ Free software means that our customers and friends can become our
collaborators, and we certainly appreciate this level of
- contribution.
+ contribution!
</para>
<para>
Have fun using these products, and we hope to meet all of you
<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 airframe.
+ 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 interface for
- communicating with the altimeters. Combined with your choice of antenna and
+ Complementing TeleMetrum and TeleMini is TeleDongle, a USB to RF
+ interface for communicating with the altimeters. Combined with your
+ choice of antenna and
notebook computer, TeleDongle and our associated user interface software
form a complete ground station capable of logging and displaying in-flight
telemetry, aiding rocket recovery, then processing and archiving flight
The TeleMetrum battery can be charged by plugging it into the
corresponding socket of the TeleMetrum and then using the USB A to
mini B
- cable to plug the Telemetrum into your computer's USB socket. The
+ cable to plug the TeleMetrum into your computer's USB socket. The
TeleMetrum circuitry will charge the battery whenever it is plugged
in, because the TeleMetrum's on-off switch does NOT control the
charging circuitry.
<para>
When the GPS chip is initially searching for
satellites, TeleMetrum will consume more current than it can pull
- from the usb port, so the battery must be attached in order to get
+ from the USB port, so the battery must be attached in order to get
satellite lock. Once GPS is locked, the current consumption goes back
down enough to enable charging while
running. So it's a good idea to fully charge the battery as your
ugly bugs in some earlier versions.
</para>
<para>
- Next you should obtain and install the AltOS utilities. These include
+ Next you should obtain and install the AltOS software. These include
the AltosUI ground station program, current firmware images for
- TeleMetrum, TeleMini and TeleDongle, and a number of standalone utilities that
- are rarely needed. Pre-built binary packages are available for Debian
- Linux, Microsoft Windows, and recent MacOSX versions. Full sourcecode
- and build instructions for some other Linux variants are also available.
+ TeleMetrum, TeleMini and TeleDongle, and a number of standalone
+ utilities that are rarely needed. Pre-built binary packages are
+ available for Linux, Microsoft Windows, and recent MacOSX versions.
+ Full source code and build instructions are also available.
The latest version may always be downloaded from
<ulink url="http://altusmetrum.org/AltOS"/>.
</para>
<title>Handling Precautions</title>
<para>
All Altus Metrum products are sophisticated electronic devices.
- When handled gently and properly installed in an airframe, they
- will deliver impressive results. However, like all electronic
+ When handled gently and properly installed in an air-frame, they
+ will deliver impressive results. However, as with all electronic
devices, there are some precautions you must take.
</para>
<para>
or their leads are allowed to short, they can and will release their
energy very rapidly!
Thus we recommend that you take some care when handling our batteries
- and consider giving them some extra protection in your airframe. We
+ and consider giving them some extra protection in your air-frame. We
often wrap them in suitable scraps of closed-cell packing foam before
strapping them down, for example.
</para>
and all of the other surface mount components
are "down" towards whatever the underlying mounting surface is, so
this is not normally a problem. Please consider this, though, when
- designing an installation, for example, in an airframe with a
+ designing an installation, for example, in an air-frame with a
see-through plastic payload bay. It is particularly important to
consider this with TeleMini, both because the baro sensor is on the
"top" of the board, and because many model rockets with payload bays
<title>Hardware Overview</title>
<para>
TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
- fit inside coupler for 29mm airframe tubing, but using it in a tube that
+ fit inside coupler for 29mm air-frame tubing, but using it in a tube that
small in diameter may require some creativity in mounting and wiring
- to succeed! The default 1/4
- wave UHF wire antenna attached to the center of the nose-cone end of
- the board is about 7 inches long, and wiring for a power switch and
+ to succeed! The presence of an accelerometer means TeleMetrum should
+ be aligned along the flight axis of the airframe, and by default the 1/4
+ wave UHF wire antenna should be on the nose-cone end of the board. The
+ antenna wire is about 7 inches long, and wiring for a power switch and
the e-matches for apogee and main ejection charges depart from the
- fin can end of the board. Given all this, an ideal "simple" avionics
+ fin can end of the board, meaning an ideal "simple" avionics
bay for TeleMetrum should have at least 10 inches of interior length.
</para>
<para>
TeleMini is a 0.5 inch by 1.5 inch circuit board. It was designed to
- fit inside an 18mm airframe tube, but using it in a tube that
+ fit inside an 18mm air-frame tube, but using it in a tube that
small in diameter may require some creativity in mounting and wiring
- to succeed! The default 1/4
- wave UHF wire antenna attached to the center of the nose-cone end of
+ to succeed! Since there is no accelerometer, TeleMini can be mounted
+ in any convenient orientation. The default 1/4
+ wave UHF wire antenna attached to the center of one end of
the board is about 7 inches long, and wiring for a power switch and
the e-matches for apogee and main ejection charges depart from the
- fin can end of the board. Given all this, an ideal "simple" avionics
+ other end of the board, meaning an ideal "simple" avionics
bay for TeleMini should have at least 9 inches of interior length.
</para>
<para>
- A typical TeleMetrum or TeleMini installation using the on-board devices and
- default wire UHF antenna involves attaching only a suitable
- Lithium Polymer battery, a single pole switch for power on/off, and
- two pairs of wires connecting e-matches for the apogee and main ejection
- charges.
+ A typical TeleMetrum or TeleMini installation involves attaching
+ only a suitable Lithium Polymer battery, a single pole switch for
+ power on/off, and two pairs of wires connecting e-matches for the
+ apogee and main ejection charges.
</para>
<para>
- By default, we use the unregulated output of the LiPo battery directly
+ By default, we use the unregulated output of the Li-Po battery directly
to fire ejection charges. This works marvelously with standard
low-current e-matches like the J-Tek from MJG Technologies, and with
- Quest Q2G2 igniters. However, if you
- want or need to use a separate pyro battery, check out the "External Pyro Battery"
- section in this manual for instructions on how to wire that up. The
- altimeters are designed to work with an external pyro battery of up to 15V.
+ Quest Q2G2 igniters. However, if you want or need to use a separate
+ pyro battery, check out the "External Pyro Battery" section in this
+ manual for instructions on how to wire that up. The altimeters are
+ designed to work with an external pyro battery of no more than 15 volts.
</para>
<para>
Ejection charges are wired directly to the screw terminal block
- at the aft end of the altimeter. This is very similar to what
- most other altimeter vendors provide and so may be the most
- familiar option. You'll need a very small straight blade
- screwdriver to connect and disconnect the board in this case,
- such as you might find in a jeweler's screwdriver set.
+ at the aft end of the altimeter. You'll need a very small straight
+ blade screwdriver for these screws, such as you might find in a
+ jeweler's screwdriver set.
</para>
<para>
TeleMetrum also uses the screw terminal block for the power
switch leads. On TeleMini, the power switch leads are soldered
- directly to the board and can be connected directly to the switch.
+ directly to the board and can be connected directly to a switch.
</para>
<para>
- For most airframes, the integrated antennas are more than
- adequate However, if you are installing in a carbon-fiber
- electronics bay which is opaque to RF signals, you may need to
+ For most air-frames, the integrated antennas are more than
+ adequate. However, if you are installing in a carbon-fiber or
+ metal electronics bay which is opaque to RF signals, you may need to
use off-board external antennas instead. In this case, you can
order an altimeter with an SMA connector for the UHF antenna
connection, and, on TeleMetrum, you can unplug the integrated GPS
<para>
The AltOS firmware build for the altimeters has two
fundamental modes, "idle" and "flight". Which of these modes
- the firmware operates in is determined at startup time. For
+ the firmware operates in is determined at start up time. For
TeleMetrum, the mode is controlled by the orientation of the
rocket (well, actually the board, of course...) at the time
power is switched on. If the rocket is "nose up", then
TeleMetrum assumes it's on a rail or rod being prepared for
launch, so the firmware chooses flight mode. However, if the
rocket is more or less horizontal, the firmware instead enters
- idle mode. For TeleMini, "idle" mode is selected when the
+ idle mode. Since TeleMini doesn't have an accelerometer we can
+ use to determine orientation, "idle" mode is selected when the
board receives a command packet within the first five seconds
of operation; if no packet is received, the board enters
"flight" mode.
</para>
<para>
At power on, you will hear three beeps or see three flashes
- ("S" in Morse code for startup) and then a pause while
- the altimeter completes initialization and self tests, and decides which
- mode to enter next.
+ ("S" in Morse code for start up) and then a pause while
+ the altimeter completes initialization and self test, and decides
+ which mode to enter next.
</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.
flights, do what makes sense.
</para>
<para>
- In idle mode, you will hear an audible "di-dit" or see two short flashes ("I" for idle), and
- the normal flight state machine is disengaged, thus
- no ejection charges will fire. The altimeters also listen on the RF
- link when in idle mode for packet mode requests sent from TeleDongle.
- Commands can be issued to a TeleMetrum in idle mode over either
- USB or the RF link equivalently. TeleMini uses only the RF link.
+ 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 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 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.
</para>
<para>
- One "neat trick" of particular value when the altimeter is used with very
- large airframes, 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 airframe to launch position, use a TeleDongle to open
- a packet connection, and issue a 'reset' command which will 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 installing
- igniters!
+ One "neat trick" of particular value when TeleMetrum is used with
+ 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 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
+ installing igniters!
</para>
</section>
<section>
<title>GPS </title>
<para>
- TeleMetrum includes a complete GPS receiver. See a later section for
- a brief explanation of how GPS works that will help you understand
- the information in the telemetry stream. The bottom line is that
- the TeleMetrum GPS receiver needs to lock onto at least four
- satellites to obtain a solid 3 dimensional position fix and know
- what time it is!
+ TeleMetrum includes a complete GPS receiver. A complete explanation
+ of how GPS works is beyond the scope of this manual, but the bottom
+ line is that the TeleMetrum GPS receiver needs to lock onto at least
+ four satellites to obtain a solid 3 dimensional position fix and know
+ what time it is.
</para>
<para>
- TeleMetrum provides backup power to the GPS chip any time a LiPo
+ TeleMetrum provides backup power to the GPS chip any time a
battery is connected. This allows the receiver to "warm start" on
- the launch rail much faster than if every power-on were a "cold start"
- for the GPS receiver. In typical operations, powering up TeleMetrum
- on the flight line in idle mode while performing final airframe
+ the launch rail much faster than if every power-on were a GPS
+ "cold start". In typical operations, powering up TeleMetrum
+ on the flight line in idle mode while performing final air-frame
preparation will be sufficient to allow the GPS receiver to cold
start and acquire lock. Then the board can be powered down during
RSO review and installation on a launch rod or rail. When the board
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 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. 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>
+ 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>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,
- this can be accomplished in a TeleMetrum- or TeleMini- equipped rocket without as
- much work as you may be accustomed to with other systems. It can
- even be fun!
+ 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!
</para>
<para>
Just prep the rocket for flight, then power up the altimeter
- in "idle" mode (placing airframe horizontal for TeleMetrum or
- starting the RF packet connection for TeleMini). This will cause the
- firmware to go into "idle" mode, in which the normal flight
+ in "idle" mode (placing air-frame horizontal for TeleMetrum or
+ selected the Configure Altimeter tab for TeleMini). This will cause
+ the firmware to go into "idle" mode, in which the normal flight
state machine is disabled and charges will not fire without
- manual command. Then, establish an RF packet connection from
- a TeleDongle-equipped computer using the P command from a safe
- distance. You can now command the altimeter to fire the apogee
- or main charges to complete your testing.
- </para>
- <para>
- In order to reduce the chance of accidental firing of pyrotechnic
- charges, the command to fire a charge is intentionally somewhat
- difficult to type, and the built-in help is slightly cryptic to
- prevent accidental echoing of characters from the help text back at
- the board from firing a charge. The command to fire the apogee
- drogue charge is 'i DoIt drogue' and the command to fire the main
- charge is 'i DoIt main'.
+ manual command. You can now command the altimeter to fire the apogee
+ or main charges from a safe distance using your computer and
+ TeleDongle and the Fire Igniter tab to complete ejection testing.
</para>
</section>
<section>
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 airframe. However, when the board is in "flight
+ 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>
- We don't use a 'normal packet radio' mode because they're just too
- inefficient. The GFSK modulation we use is just FSK with the
- baseband pulses passed through a
+ We don't use a 'normal packet radio' mode like APRS because they're
+ just too inefficient. The GFSK modulation we use is FSK with the
+ base-band pulses passed through a
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 good 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 soon, and would
- of course appreciate customer feedback on performance in higher
- altitude flights!
+ 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. Through the use of a Kalman filter, there is no need
- to set a "mach delay" . The few configurable parameters can
- all be set using a simple terminal program over the USB port
- or RF link via TeleDongle.
+ 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 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 -- 100kHz channels starting at
- 434.550MHz. However, you can configure the firmware to use
+ 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
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):
+ the standard calibration reference frequency, 'S', (normally 434.550MHz):
<programlisting>
R = F / S * C
</programlisting>
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
- airframes this way quite happily, including Keith's
+ air-frames this way quite happily, including Keith's
successful L3 cert.
</para>
</section>
<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 airframes, but feel free to change 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
<section>
<title>Radio Frequency</title>
<para>
- The radio frequency is synthesized from a clock based on the 48 Mhz
+ 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
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
+ 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'
<section>
<title>TeleMetrum Accelerometer</title>
<para>
- The TeleMerum accelerometer we use has its own 5 volt power supply and
+ 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 ratiometric to
+ 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,
<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,
+ 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
the TeleMetrum with new firmware, showing a progress bar.
</listitem>
<listitem>
- Confirm that the TeleMetrum board seems to have updated ok, which you
+ 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.
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
+ 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>
the TeleDongle with new firmware, showing a progress bar.
</listitem>
<listitem>
- Confirm that the TeleDongle board seems to have updated ok, which you
+ 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
<para>
The radio frequency being monitored by the TeleDongle device is
displayed at the top of the window. You can configure the
- frequecy by clicking on the frequency box and selecting the desired
+ frequency by clicking on the frequency box and selecting the desired
frequency. AltosUI remembers the last frequency selected for each
TeleDongle and selects that automatically the next time you use
that device.
</para>
<itemizedlist>
<listitem>
- <para>The configured callsign</para>
+ <para>The configured call-sign</para>
</listitem>
<listitem>
<para>The device serial number</para>
The Received Signal Strength Indicator value. This lets
you know how strong a signal TeleDongle is receiving. The
radio inside TeleDongle operates down to about -99dBm;
- weaker signals may not be receiveable. The packet link uses
+ weaker signals may not be receivable. The packet link uses
error correction and detection techniques which prevent
incorrect data from being reported.
</para>
<itemizedlist>
<listitem>
<para>
- Battery Voltage. This indicates whether the LiPo battery
+ Battery Voltage. This indicates whether the Li-Po battery
powering the TeleMetrum has sufficient charge to last for
the duration of the flight. A value of more than
3.7V is required for a 'GO' status.
Apogee Igniter Voltage. This indicates whether the apogee
igniter has continuity. If the igniter has a low
resistance, then the voltage measured here will be close
- to the LiPo battery voltage. A value greater than 3.2V is
+ to the Li-Po battery voltage. A value greater than 3.2V is
required for a 'GO' status.
</para>
</listitem>
Main Igniter Voltage. This indicates whether the main
igniter has continuity. If the igniter has a low
resistance, then the voltage measured here will be close
- to the LiPo battery voltage. A value greater than 3.2V is
+ to the Li-Po battery voltage. A value greater than 3.2V is
required for a 'GO' status.
</para>
</listitem>
+ <listitem>
+ <para>
+ On-board Data Logging. This indicates whether there is
+ space remaining on-board to store flight data for the
+ upcoming flight. If you've downloaded data, but failed
+ to erase flights, there may not be any space
+ left. TeleMetrum can store multiple flights, depending
+ on the configured maximum flight log size. TeleMini
+ stores only a single flight, so it will need to be
+ downloaded and erased after each flight to capture
+ data. This only affects on-board flight logging; the
+ altimeter will still transmit telemetry and fire
+ ejection charges at the proper times.
+ </para>
+ </listitem>
<listitem>
<para>
GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
</listitem>
</itemizedlist>
<para>
- The LaunchPad tab also shows the computed launch pad position
+ The Launchpad tab also shows the computed launch pad position
and altitude, averaging many reported positions to improve the
accuracy of the fix.
</para>
</para>
<para>
The height, speed and acceleration are shown along with the
- maxium values for each of them. This allows you to quickly
+ maximum values for each of them. This allows you to quickly
answer the most commonly asked questions you'll hear during
flight.
</para>
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
- latitude and longitude and enter them into your handheld GPS
+ latitude and longitude and enter them into your hand-held GPS
unit and have that compute a track to the landing location.
</para>
<para>
When the TeleMetrum gets 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 colour: white for pad, red for
+ rocket's state is indicated by color: white for pad, red for
boost, pink for fast, yellow for coast, light blue for drogue,
dark blue for main, and black for landed.
</para>
<para>
The map's scale is approximately 3m (10ft) per pixel. The map
can be dragged using the left mouse button. The map will attempt
- to keep the rocket roughly centred while data is being received.
+ to keep the rocket roughly centered while data is being received.
</para>
<para>
Images are fetched automatically via the Google Maps Static API,
and are cached for reuse. If map images cannot be downloaded,
- the rocket's path will be traced on a dark grey background
+ the rocket's path will be traced on a dark gray background
instead.
</para>
<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 airframe 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 airframe. 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>
data will be recorded for a flight.
</para>
<para>
- The filename for each flight log is computed automatically
+ The file name for each flight log is computed automatically
from the recorded flight date, altimeter serial number and
flight number information.
</para>
dragging down and to the right. Once zoomed, the graph can be
reset by clicking and dragging up and to the left. Holding down
control and clicking and dragging allows the graph to be panned.
- The right mouse button causes a popup menu to be displayed, giving
+ The right mouse button causes a pop-up menu to be displayed, giving
you the option save or print the plot.
</para>
<para>
<para>
Select this button and then select either a TeleMetrum or
TeleDongle Device from the list provided. Selecting a TeleDongle
- device will use Packet Comamnd Mode to configure a remote
+ device will use Packet Command Mode to configure a remote
altimeter. Learn how to use this in the Packet Command
Mode chapter.
</para>
<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 overpressurize the apogee deployment
- bay and cause a structural failure of the airframe. The Apogee
+ 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
detected.
<section>
<title>Callsign</title>
<para>
- This sets the callsign included in each telemetry packet. Set this
+ This sets the call sign included in each telemetry packet. Set this
as needed to conform to your local radio regulations.
</para>
</section>
<section>
<title>Voice Settings</title>
<para>
- AltosUI provides voice annoucements during flight so that you
+ AltosUI provides voice announcements during flight so that you
can keep your eyes on the sky and still get information about
the current flight status. However, sometimes you don't want
to hear them.
<listitem>
<para>
Test Voice—Plays a short message allowing you to verify
- that the audio systme is working and the volume settings
+ that the audio system is working and the volume settings
are reasonable
</para>
</listitem>
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
- with the AltosUI operators callsign as needed to comply with
+ with the AltosUI operators call sign as needed to comply with
your local radio regulations.
</para>
</section>
recovery systems deployment. Because this command can operate
over the Packet Command Link, you can prepare the rocket as
for flight and then test the recovery system without needing
- to snake wires inside the airframe.
+ to snake wires inside the air-frame.
</para>
<para>
Selecting the 'Fire Igniter' button brings up the usual device
selection dialog. Pick the desired TeleDongle or TeleMetrum
device. This brings up another window which shows the current
- continutity test status for both apogee and main charges.
+ continuity test status for both apogee and main charges.
</para>
<para>
Next, select the desired igniter to fire. This will enable the
<para>
In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
<ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
- a LiPo rechargeable battery. An 860mAh battery weighs less than a 9V
+ a Li-Po rechargeable battery. An 860mAh battery weighs less than a 9V
alkaline battery, and will run a TeleMetrum for hours.
A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
a few hours, or a TeleMini for much (much) longer.
</para>
<para>
By default, we ship the altimeters with a simple wire antenna. If your
- electronics bay or the airframe it resides within is made of carbon fiber,
+ electronics bay or the air-frame it resides within is made of carbon fiber,
which is opaque to RF signals, you may choose to have an SMA connector
installed so that you can run a coaxial cable to an antenna mounted
elsewhere in the rocket.
<title>On the Ground</title>
<para>
To receive the data stream from the rocket, you need an antenna and short
- feedline connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. The
+ feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. The
TeleDongle in turn plugs directly into the USB port on a notebook
computer. Because TeleDongle looks like a simple serial port, your computer
does not require special device drivers... just plug it in.
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 LiPo
+ the rocket is pretty cool! A USB cable is also how you charge the Li-Po
battery, so you'll want one of those anyway... the same cable used by lots
of digital cameras and other modern electronic stuff will work fine.
</para>
<para>
- If your TeleMetrum-equiped rocket lands out of sight, you may enjoy having a hand-held GPS
- receiver, so that you can put in a waypoint for the last reported rocket
+ If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
+ receiver, so that you can put in a way-point for the last reported rocket
position before touch-down. This makes looking for your rocket a lot like
- Geo-Cacheing... just go to the waypoint and look around starting from there.
+ Geo-Caching... just go to the way-point and look around starting from there.
</para>
<para>
You may also enjoy having a ham radio "HT" that covers the 70cm band... you
So, to recap, on the ground the hardware you'll need includes:
<orderedlist inheritnum='inherit' numeration='arabic'>
<listitem>
- an antenna and feedline
+ an antenna and feed-line
</listitem>
<listitem>
a TeleDongle
a notebook computer
</listitem>
<listitem>
- optionally, a handheld GPS receiver
+ optionally, a hand-held GPS receiver
</listitem>
<listitem>
- optionally, an HT or receiver covering 435 Mhz
+ optionally, an HT or receiver covering 435 MHz
</listitem>
</orderedlist>
</para>
<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 postflight tools make it
+ 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,
max acceleration, and max velocity. You can also generate and view a
standard set of plots showing the altitude, acceleration, and
velocity of the rocket during flight. And you can even export a TeleMetrum data file
- useable with Google Maps and Google Earth for visualizing the flight path
+ usable with Google Maps and Google Earth for visualizing the flight path
in two or three dimensions!
</para>
<para>
Building high-power rockets that fly safely is hard enough. Mix
in some sophisticated electronics and a bunch of radio energy
and oftentimes you find few perfect solutions. This chapter
- contains some suggestions about how to install AltusMetrum
- products into the rocket airframe, including how to safely and
- reliably mix a variety of electronics into the same airframe.
+ contains some suggestions about how to install Altus Metrum
+ products into the rocket air-frame, including how to safely and
+ reliably mix a variety of electronics into the same air-frame.
</para>
<section>
<title>Mounting the Altimeter</title>
<para>
The first consideration is to ensure that the altimeter is
- securely fastened to the airframe. For TeleMetrum, we use
+ securely fastened to the air-frame. For TeleMetrum, we use
nylon standoffs and nylon screws; they're good to at least 50G
and cannot cause any electrical issues on the board. For
TeleMini, we usually cut small pieces of 1/16" balsa to fit
wire. If it gets damaged or broken, it can be easily
replaced. It should be kept straight and not cut; bending or
cutting it will change the resonant frequency and/or
- impedence, making it a less efficient radiator and thus
+ impedance, making it a less efficient radiator and thus
reducing the range of the telemetry signal.
</para>
<para>
</para>
<para>
Make sure the antenna is not inside a tube made or covered
- with conducting material. Carbon fibre is the most common
+ with conducting material. Carbon fiber is the most common
culprit here -- CF is a good conductor and will effectively
shield the antenna, dramatically reducing signal strength and
- range. Metalic flake paint is another effective shielding
+ range. Metallic flake paint is another effective shielding
material which is to be avoided around any antennas.
</para>
<para>
<orderedlist inheritnum='inherit' numeration='arabic'>
<listitem>
Conductive tubing or coatings. Carbon fiber and metal
- tubing, or metalic paint will all dramatically attenuate the
+ tubing, or metallic paint will all dramatically attenuate the
GPS signal. We've never heard of anyone successfully
receiving GPS from inside these materials.
</listitem>
<para>
To accurately measure atmospheric pressure, the ebay
containing the altimeter must be vented outside the
- airframe. The vent must be placed in a region of linear
+ air-frame. The vent must be placed in a region of linear
airflow, smooth and not in an area of increasing or decreasing
pressure.
</para>
<title>Ground Testing</title>
<para>
The most important aspect of any installation is careful
- ground testing. Bringing an airframe up to the LCO table which
+ 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.
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 airframe sit for several minutes, checking for
+ time. Let the air-frame sit for several minutes, checking for
adequate telemetry signal strength and GPS lock.
</para>
<para>
Ground test the ejection charges. Prepare the rocket for
flight, loading ejection charges and igniters. Completely
- assemble the airframe and then use the 'Fire Igniters'
+ 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 airframe and deploy the recovery system.
+ the air-frame and deploy the recovery system.
</para>
</section>
</chapter>
</listitem>
<listitem>
<para>
- 70cm ham-band transceiver for telemetry downlink.
+ 70cm ham-band transceiver for telemetry down-link.
</para>
</listitem>
<listitem>
</listitem>
<listitem>
<para>
- On-board, integrated GPS receiver with 5hz update rate capability.
+ On-board, integrated GPS receiver with 5Hz update rate capability.
</para>
</listitem>
<listitem>
</listitem>
<listitem>
<para>
- Fully integrated support for LiPo rechargeable batteries.
+ Fully integrated support for Li-Po rechargeable batteries.
</para>
</listitem>
<listitem>
<para>
- Uses LiPo to fire e-matches, can be modiied to support
+ Uses Li-Po to fire e-matches, can be modified to support
optional separate pyro battery if needed.
</para>
</listitem>
<listitem>
<para>
- 2.75 x 1 inch board designed to fit inside 29mm airframe coupler tube.
+ 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
- 70cm ham-band transceiver for telemetry downlink.
+ 70cm ham-band transceiver for telemetry down-link.
</para>
</listitem>
<listitem>
</listitem>
<listitem>
<para>
- Support for LiPo rechargeable batteries, using an external charger.
+ Support for Li-Po rechargeable batteries, using an external charger.
</para>
</listitem>
<listitem>
<para>
- Uses LiPo to fire e-matches, can be modiied to support
+ Uses Li-Po to fire e-matches, can be modified to support
optional separate pyro battery if needed.
</para>
</listitem>
<listitem>
<para>
- 1.5 x .5 inch board designed to fit inside 18mm airframe coupler tube.
+ 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
</para>
</listitem>
</itemizedlist>
<para>
There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
That's the "pad" mode. Weak batteries might be the problem.
- It is also possible that the Telemetrum is horizontal and the output
+ It is also possible that the TeleMetrum is horizontal and the output
is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
it received a command packet which would have left it in "pad" mode.
</para>
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
- along the rf data path.
+ 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
the on-board data after each flight; while the TeleMetrum can store
</emphasis>
</para>
<para>
- Both Telemetrum and TeleDongle can be directly communicated
+ Both TeleMetrum and TeleDongle can be directly communicated
with using USB ports. The first thing you should try after getting
- both units plugged into to your computer's usb port(s) is to run
+ both units plugged into to your computer's USB port(s) is to run
'ao-list' from a terminal-window to see what port-device-name each
device has been assigned by the operating system.
You will need this information to access the devices via their
for these options and so they'll all be lost when you unplug it.
</para>
<para>
- Try setting these config ('c' or second level menu) values. A good
+ Try setting these configuration ('c' or second level menu) values. A good
place to start is by setting your call sign. By default, the boards
use 'N0CALL' which is cute, but not exactly legal!
Spend a few minutes getting comfortable with the units, their
</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.
of being powered up, otherwise it enters "pad" mode.
</para>
<para>
- You can access an altimeter in idle mode from the Teledongle's USB
- connection using the rf link
+ You can access an altimeter in idle mode from the TeleDongle's USB
+ 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
rocket vertically on the launch pad, walk away and then issue a
reboot command. The altimeter will reboot and start sending data
having changed to the "pad" mode. If the TeleDongle is not receiving
- this data, you can disconnect 'cu' from the Teledongle using the
+ this data, you can disconnect 'cu' from the TeleDongle using the
procedures mentioned above and THEN connect to the TeleDongle from
inside 'ao-view'. If this doesn't work, disconnect from the
TeleDongle, unplug it, and try again after plugging it back in.
</para>
+ <para>
+ In order to reduce the chance of accidental firing of pyrotechnic
+ charges, the command to fire a charge is intentionally somewhat
+ difficult to type, and the built-in help is slightly cryptic to
+ prevent accidental echoing of characters from the help text back at
+ the board from firing a charge. The command to fire the apogee
+ drogue charge is 'i DoIt drogue' and the command to fire the main
+ charge is 'i DoIt main'.
+ </para>
<para>
On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
- and 'ao-view' will both auditorially announce and visually indicate
+ and 'ao-view' will both auditorily announce and visually indicate
that GPS is ready.
Now you can launch knowing that you have a good data path and
good satellite lock for flight data and recovery. Remember
contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
either a USB cable or over the radio link using TeleDongle.
And by following the man page for 'ao-postflight' you can create
- various data output reports, graphs, and even kml data to see the
- flight trajectory in google-earth. (Moving the viewing angle making
- sure to connect the yellow lines while in google-earth is the proper
+ various data output reports, graphs, and even KML data to see the
+ flight trajectory in Google-earth. (Moving the viewing angle making
+ sure to connect the yellow lines while in Google-earth is the proper
technique.)
</para>
<para>
<xi:include href="release-notes-0.7.1.xsl" xpointer="xpointer(/article/*)"/>
</appendix>
</book>
+
+<!-- LocalWords: Altusmetrum
+-->