For the latest TeleMetrum firmware and related ground station software, please
visit the [AltOS](../AltOS) page on this site.
-These are photos of our current production version:
+These are photos of the previous production version (we haven't taken good
+pictures of v1.2 yet):
<a href="v1.1/telemetrum-v1.1-thside.jpg"> <img src="v1.1/telemetrum-v1.1-thside-thumb.jpg"></a>
<a href="v1.1/telemetrum-v1.1-smtside.jpg"> <img src="v1.1/telemetrum-v1.1-smtside-thumb.jpg"></a>
* Supports dual deployment (can fire 2 ejection charges)
* 70cm ham-band transceiver for telemetry downlink
* Barometric pressure sensor good to 45k feet MSL
-* 1-axis high-g accelerometer for motor characterization
+* 1-axis 70-g accelerometer for motor characterization
* On-board, integrated GPS receiver
* On-board non-volatile memory for flight data storage
* USB for power, configuration, and data recovery
* U.FL connector with 3.3V DC can be re-purposed for optional external amplified antennas
* async serial interface
* [Freescale MP3H6115A](http://www.freescale.com/webapp/search.partparamdetail.framework?PART_NUMBER=MP3H6115A6U) pressure sensor
- * [Freescale MMA2202EG](http://www.freescale.com/webapp/search.partparamdetail.framework?PART_NUMBER=MMA2202EG) 50g accelerometer. Can use 40-200g variants!
+ * [Analog Devices ADXL78](http://www.analog.com/en/mems-sensors/inertial-sensors/adxl78/products/product.html) 70g accelerometer.
* Software Features
* Written mostly in C with some 8051 assembler
* Runs from on-chip flash, uses on-chip RAM, stores flight data to
newer versions have their own PCB design.
For those who don't have ready access to the gEDA suite, here are pdf snapshots
-of the files for Production PCB version 1.1 in more easily readable form.
+of the files for Production PCB version 1.2 in more easily readable form.
-* [schematic](v1.1/telemetrum.pdf)
-* [pcb artwork](v1.1/telemetrum.pcb.pdf)
-* [bill of materials](v1.1/partslist.csv)
+* [schematic](v1.2/telemetrum.pdf)
+* [pcb artwork](v1.2/telemetrum.pcb.pdf)
+* [bill of materials](v1.2/partslist.csv)
Rockets we know of flying with TeleMetrum boards have exceeded 50g acceleration,
been well above Mach 1, and reached altitudes
## Future Plans ##
-TeleMetrum v1.2 is back from our assembler and the first batch are being
-prepared for sale, hopefully by Christmas day. The significant user-visible
-change is that we've moved to a 70g accelerometer by default, due to poor
-availability of the part we previously used due to damage to the Freescale
-facility in Sendai caused by the Japan earthquake / tsunami. Full details
-will be posted here when they're available to order.
+TeleMetrum v1.2 is now available for sale. Eventually we'll run out of v1.2
+boards, and by then no dobut we'll have found more things to tweak...
-## Problems ##
+## [History of TeleMetrum](history) ##
-* The CC1111F32 is a 36-pin QFN package, which necessitates reflow
- soldering. Since we needed to reflow solder anyway, and because TI used
- them in their reference design, we went a little crazy and used 0402
- passive parts everywhere. That means working under a microscope to
- place parts! Without an inspection microscope, loading and testing these
- boards might be impossible.
-
-* The addition of on-board GPS in v0.2 and later boards means that the total
- power consumption
- can exceed the rate at which we draw power from the USB interface,
- particularly when the GPS is in cold start mode. This means a battery must
- be attached during operation, and also that the battery will only charge
- effectively from USB when the board is turned off.
-
-## History ##
-
-### v1.0 ###
-
-These are photos of our third version, which was the basis of our first
-production build. These were sold between April and December 2010, and
-performed very well.
-
-<a href="v1.0/cimg5972-crop.jpg"> <img src="v1.0/cimg5972-thumb.jpg"></a>
-<a href="v1.0/cimg5974-crop.jpg"> <img src="v1.0/cimg5974-thumb.jpg"></a>
-
-The differences between v1.0 and v1.1 were small:
-
-* different flash memory part due to supplier availability problems
-* updated reset circuit to improve reliability at temperature extremes
-* changed the GPS antenna footprint to eliminate the large through-hole
- originally intended for use with a passive patch
-* irq line eliminated from the companion port
-* an additional resistor divider added to allow sampling the 5V supply
-
-The schematics and PCB artwork for this version are on the v1.0 branch in
-our git repository, here are pdf copies for easy reference:
-
-* [schematic](v1.0/telemetrum.pdf)
-* [pcb artwork](v1.0/telemetrum.pcb.pdf)
-* [bill of materials](v1.0/partslist.csv)
-
-
-### v0.2 ###
-
-These are photos of our second version, which included the integrated Venus
-GPS receiver, but with a passive patch antenna that turned out to have
-disappointing performance due to our many PCB geometry constraints. It also
-used a voltage regulator with less capacity which we felt was marginal for
-supporting the companion boards we have planned:
-
-<a href="v0.2/cimg5164-cropped.jpg"> <img src="v0.2/cimg5164-thumb.jpg"></a>
-<a href="v0.2/cimg5171-cropped.jpg"> <img src="v0.2/cimg5171-thumb.jpg"></a>
-
-Other than cleaning up the silkscreen, the differences between v0.2 and
-v1.0 boards were really quite small:
-
-* 100ma LDO regulator instead of the current 150ma part
-* no C38 footprint
-* different value for C36 reset capacitor
-
-The schematics and PCB artwork for this version are on the v0.2 branch in
-our git repository, here are pdf copies for easy reference:
-
- * [schematic](v0.2/telemetrum.pdf)
- * [pcb artwork](v0.2/telemetrum.pcb.pdf)
- * [bill of materials](v0.2/partslist.csv)
-
-### v0.1 ###
-
-And this is a photo of our original board with serial port for off-board GPS,
-without the big off-board 1000uF cap from the original ejection circuit:
-
-<a href="v0.1/loadedpair.jpg"> <img src="v0.1/loadedpair-thumb.jpg"></a>
-
-The differences between v0.1 and later boards were substantial:
-
-* 2.5 x 1 inch board with all parts mounted on one side
-* 4-pin PicoBlade serial port connector for attachment of external GPS module
-* USB connector projected approximately 3mm over the edge of the board
-* Debug connector used 4 IC socket pins on 100 mil centers
-* no companion board interface
-* 50ma LDO regulator on early boards, later boards used a 100ma part
-* [Microchip 25LC1024](http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en520389) CMOS serial EEPROM instead of DataFlash
- * 128k x 8
- * SPI interface
-* [Microchip MCP9700A](http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en027103) discrete temperature sensor
-* used 1000uF electrolytic capacitor charged to 5V for pyro supply
-* two LEDs instead of one attached to CPU
-
-The elimination of the discrete temperature sensor and second LED were
-necessary to support the companion board interface added in v0.2.
-
-The v0.1 artwork had three issues, two of which required physical rework
-on each board. All of these issues were fixed in v0.2.
-
-* The USB connector footprint was placed wrong, so that the
- connector hung out over the edge of the board instead of being
- flush.
-* We needed chip select on the SPI memory. To fix that, we gave up the
- ability to put the accelerometer into self-test mode and used that
- GPIO line to pull chip select on the memory, which required two
- cuts and two jumpers.
-* The igniter sense circuits each needed a second resistor to
- complete the voltage divider so our 3.3V CPU ADC could read the
- 5V ejection voltage. This was fixed by changing two resistor
- values, and tacking two additional resistors onto the board
- with jumpers to ground.
-
-The schematics and PCB artwork for this version as of the working-v0.1 tag
-are available here are pdf copies for easy reference:
-
- * [schematic](v0.1/telemetrum.pdf)
- * [pcb artwork](v0.1/telemetrum.pcb.pdf)
- * [bill of materials](v0.1/telemetrum.bom)