3 This is a recording dual-deploy altimeter for high power model rocketry
4 with integrated GPS and telemetry link.
6 Production units will be available soon from the
7 [Garbee and Garbee](http://auric.gag.com) web store.
9 These are photos of our current version,
10 which includes an integrated GPS receiver and patch antenna:
12 <a href="v0.2/cimg5164-cropped.jpg"> <img src="v0.2/cimg5164-thumb.jpg"></a>
13 <a href="v0.2/cimg5171-cropped.jpg"> <img src="v0.2/cimg5171-thumb.jpg"></a>
15 And this is a photo of our original board with serial port for off-board GPS,
16 without the big off-board 1000uF cap from the original ejection circuit:
18 <a href="v0.1/loadedpair.jpg"> <img src="v0.1/loadedpair-thumb.jpg"></a>
22 Bdale and Keith both own
23 [BeeLine](http://www.bigredbee.com/BeeLine.htm)
25 [Big Red Bee](http://www.bigredbee.com), and are pretty happy with them.
26 They use a PIC processor and a TI CC1050 transmitter chip, and
27 operate in the ham radio 70cm band.
29 One weekend while attending a conference together, we got to wondering if
30 we couldn't adapt one to use as a downlink for the
31 [AltusMetrum](../AltusMetrum/) altimeter board in addition to direction
32 finding after flight. That caused us to start thinking about other things
33 in the design we might want to tweak, and before long we were working on the
34 design of a new tracker board derived from the BeeLine design.
35 Another friend at the same conference showed us a board he was working on
36 using a different part in the same TI series, that integrated a transceiver
37 and CPU on the same chip.
38 It didn't take us long to realize that with such a part we could combine and
39 simplify things by building a new altimeter with integrated RF link! And
40 after gaining some experience in 2009 with a first version, we realized we
41 always want GPS on board, which lead to our current second generation boards.
47 * Recording altimeter for model rocketry
48 * Supports dual deployment (can fire 2 ejection charges)
49 * 70cm ham-band transceiver for telemetry downlink
50 * Barometric pressure sensor good to 45k feet MSL
51 * 1-axis high-g accelerometer for motor characterization
52 * On-board, integrated GPS receiver
53 * On-board non-volatile memory for flight data storage
54 * USB for power, configuration, and data recovery
55 * Integrated support for LiPo rechargeable batteries
56 * Uses LiPo to fire e-matches, optional support for separate pyro battery
57 * 2.75 x 1 inch board designed to fit inside 29mm airframe coupler tube
59 ### Developer View ###
62 * [TI CC1111F32](http://focus.ti.com/docs/prod/folders/print/cc1111f32.html) Low Power RF System-on-Chip
63 * Sub-1Ghz transceiver
68 * 6 12-bit analog inputs (11 bits with single-ended sensors)
69 * 2 channels of serial I/O
71 * [Atmel AT45DB081D](http://www.atmel.com/dyn/products/product_card.asp?part_id=3819) DataFlash memory
75 * other parts in this Atmel DataFlash series can optionally be used
76 * [SkyTraq](http://www.skytraq.com.tw/) Venus634FLPx GPS receiver
77 * on-board passive patch antenna
78 * U.FL connector with 3.3V DC for optional external amplified antenna
79 * async serial interface
80 * [Freescale MP3H6115A](http://www.freescale.com/webapp/search.partparamdetail.framework?PART_NUMBER=MP3H6115A6U) pressure sensor
81 * [Freescale MMA2202EG](http://www.freescale.com/webapp/search.partparamdetail.framework?PART_NUMBER=MMA2202EG) 50g accelerometer. Can use 40-200g variants!
83 * Written mostly in C with some 8051 assembler
84 * Runs from on-chip flash, uses on-chip RAM, stores flight data to
86 * USB serial emulation for "console" interface
88 * [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
89 * [SDCC](http://sdcc.sourceforge.net/) compiler and source debugger
91 * The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
92 * The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)
94 ### v0.1 Differences ###
96 * 2.5 x 1 inch board with all parts mounted on one side
97 * 4-pin PicoBlade serial port connector for attachment of external GPS module
98 * USB connector projected approximately 3mm over the edge of the board
99 * Debug connector used 4 IC socket pins on 100 mil centers
100 * no companion board interface
101 * [Microchip 25LC1024](http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en520389) CMOS serial EEPROM instead of DataFlash
104 * [Microchip MCP9700A](http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en027103) discrete temperature sensor
105 * used 1000uF electrolytic capacitor charged to 5V for pyro supply
106 * two LEDs instead of one attached to CPU
108 The elimination of the discrete temperature sensor and second LED were
109 necessary to support the companion board interface added in v0.2.
111 ## [Production History](../production) ##
113 ## [Flight Logs](flightlogs) ##
117 * The CC1111F32 is a 36-pin QFN package, which necessitates reflow
118 soldering. Since we needed to reflow solder anyway, and because TI used
119 them in their reference design, we went a little crazy and used 0402
120 passive parts everywhere. That means working under a microscope to
121 place parts! Without an inspection microscope, loading and testing these
122 boards might be impossible.
124 * The addition of on-board GPS in v0.2 means that the total power consumption
125 can exceed the rate at which we draw power from the USB interface,
126 particularly when the GPS is in cold start mode. This means a battery must
127 be attached during operation, and also that the battery will only charge
128 effectively from USB when the board is turned off.
130 * The v0.1 artwork had three issues, two of which required physical rework
131 on each board. All of these issues were fixed in v0.2.
133 * The USB connector footprint was placed wrong, so that the
134 connector hung out over the edge of the board instead of being
136 * We needed chip select on the SPI memory. To fix that, we gave up the
137 ability to put the accelerometer into self-test mode and used that
138 GPIO line to pull chip select on the memory, which required two
139 cuts and two jumpers.
140 * The igniter sense circuits each needed a second resistor to
141 complete the voltage divider so our 3.3V CPU ADC could read the
142 5V ejection voltage. This was fixed by changing two resistor
143 values, and tacking two additional resistors onto the board
144 with jumpers to ground.
148 The hardware design current gEDA files are available from
149 [git.gag.com](http://git.gag.com) in the project
150 [hw/telemetrum](http://git.gag.com/?p=hw/telemetrum;a=summary).
152 Work on the next version proceeds on the master branch, with occasional
153 temporary branches created when Bdale is making some major / speculative
154 change. The 'v0.2' and 'v0.1' branches document what we're actually flying
155 right now on the two respective PCB revisions. The 'ground' branch has a
156 cut-down schematic used to generate the BOM for partially loading v0.1 boards
157 to used on the ground. We call the on-the-ground version 'TeleDongle'.
159 For those who don't have ready access to the gEDA suite, here are pdf snapshots
160 of files in more easily readable form.
162 * These are from the v0.2 branch:
163 * [schematic](v0.2/telemetrum.pdf)
164 * [pcb artwork](v0.2/telemetrum.pcb.pdf)
165 * [bill of materials](v0.2/partslist.csv)
166 * These are as of the working-v0.1 tag:
167 * [schematic](v0.1/telemetrum.pdf)
168 * [pcb artwork](v0.1/telemetrum.pcb.pdf)
169 * [bill of materials](v0.1/telemetrum.bom)
171 Our [AltOS](../AltOS) firmware works well enough that we now routinely fly
172 TeleMetrum with no backup. Rockets with v0.1 boards have exceeded 50g
173 acceleration, been above Mach 1, and reached altitudes greater
174 than 12k feet AGL with great results. Keith's ground station program
175 called ao-view logs telemetry to disk, displays current and max values for
176 key parameters during flight, and even includes voice synthesis
177 during the flight so that our eyes can stay on the rockets! We have post
178 flight analysis software that makes it easy to extract data from the board,
179 analyze it, and even generate KML files for viewing flights in GoogleEarth!
180 More details on the software, including full source code and pre-built packages
181 can be found on the [AltOS](../AltOS) page on this site.
185 As of early March 2010, three prototypes of v0.2 exist and have flown with
186 great success. We will initiate a production run shortly with the goal of
187 making TeleMetrum available in assembled and tested form to others in the
188 rocketry hobby in time for the 2010 flying season.
190 Because we understand that not everyone uses Linux, we are investigating
191 the best way to make a cross-platform ground station program for use with
192 [AltOS](../AltOS), perhaps in Java...