3 This is a recording dual-deploy altimeter for high power model rocketry
4 with integrated GPS and telemetry link.
6 Production units are available from the
7 [Garbee and Garbee](http://auric.gag.com) web store.
9 These are photos of our current production version, which includes an
10 integrated GPS receiver with active patch antenna:
12 <a href="v1.0/cimg5972-crop.jpg"> <img src="v1.0/cimg5972-thumb.jpg"></a>
13 <a href="v1.0/cimg5974-crop.jpg"> <img src="v1.0/cimg5974-thumb.jpg"></a>
15 These are photos of our second version, which included the integrated Venus
16 GPS receiver, but with a passive patch antenna that turned out to have
17 disappointing performance due to our many PCB geometry constraints:
19 <a href="v0.2/cimg5164-cropped.jpg"> <img src="v0.2/cimg5164-thumb.jpg"></a>
20 <a href="v0.2/cimg5171-cropped.jpg"> <img src="v0.2/cimg5171-thumb.jpg"></a>
22 And this is a photo of our original board with serial port for off-board GPS,
23 without the big off-board 1000uF cap from the original ejection circuit:
25 <a href="v0.1/loadedpair.jpg"> <img src="v0.1/loadedpair-thumb.jpg"></a>
29 Bdale and Keith both own
30 [BeeLine](http://www.bigredbee.com/BeeLine.htm)
32 [Big Red Bee](http://www.bigredbee.com), and are pretty happy with them.
33 They use a PIC processor and a TI CC1050 transmitter chip, and
34 operate in the ham radio 70cm band.
36 One weekend while attending a conference together, we got to wondering if
37 we couldn't adapt one to use as a downlink for the
38 [AltusMetrum](../AltusMetrum/) altimeter board in addition to direction
39 finding after flight. That caused us to start thinking about other things
40 in the design we might want to tweak, and before long we were working on the
41 design of a new tracker board derived from the BeeLine design.
42 Another friend at the same conference showed us a board he was working on
43 using a different part in the same TI series, that integrated a transceiver
44 and CPU on the same chip.
45 It didn't take us long to realize that with such a part we could combine and
46 simplify things by building a new altimeter with integrated RF link! And
47 after gaining some experience in 2009 with a first version, we realized we
48 always want GPS on board, which lead to our current second generation boards.
54 * Recording altimeter for model rocketry
55 * Supports dual deployment (can fire 2 ejection charges)
56 * 70cm ham-band transceiver for telemetry downlink
57 * Barometric pressure sensor good to 45k feet MSL
58 * 1-axis high-g accelerometer for motor characterization
59 * On-board, integrated GPS receiver
60 * On-board non-volatile memory for flight data storage
61 * USB for power, configuration, and data recovery
62 * Integrated support for LiPo rechargeable batteries
63 * Uses LiPo to fire e-matches, optional support for separate pyro battery
64 * 2.75 x 1 inch board designed to fit inside 29mm airframe coupler tube
66 ### Developer View ###
69 * [TI CC1111F32](http://focus.ti.com/docs/prod/folders/print/cc1111f32.html) Low Power RF System-on-Chip
70 * Sub-1Ghz transceiver
75 * 6 12-bit analog inputs (11 bits with single-ended sensors)
76 * 2 channels of serial I/O
78 * [Atmel AT45DB081D](http://www.atmel.com/dyn/products/product_card.asp?part_id=3819) DataFlash memory
82 * other parts in this Atmel DataFlash series can optionally be used
83 * [SkyTraq](http://www.skytraq.com.tw/) Venus634FLPx GPS receiver
84 * on-board [Taoglas AP.17A.01[(http://www.taoglas.com/antennas/GPS_Antennas/Internal_GPS_-_Active_Patch_Modules/)
85 single-stage active patch antenna
86 * U.FL connector with 3.3V DC can be re-purposed for optional external amplified antennas
87 * async serial interface
88 * [Freescale MP3H6115A](http://www.freescale.com/webapp/search.partparamdetail.framework?PART_NUMBER=MP3H6115A6U) pressure sensor
89 * [Freescale MMA2202EG](http://www.freescale.com/webapp/search.partparamdetail.framework?PART_NUMBER=MMA2202EG) 50g accelerometer. Can use 40-200g variants!
91 * Written mostly in C with some 8051 assembler
92 * Runs from on-chip flash, uses on-chip RAM, stores flight data to
94 * USB serial emulation for "console" interface
96 * [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
97 * [SDCC](http://sdcc.sourceforge.net/) compiler and source debugger
99 * The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
100 * The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)
102 ### v0.1 Differences ###
104 * 2.5 x 1 inch board with all parts mounted on one side
105 * 4-pin PicoBlade serial port connector for attachment of external GPS module
106 * USB connector projected approximately 3mm over the edge of the board
107 * Debug connector used 4 IC socket pins on 100 mil centers
108 * no companion board interface
109 * [Microchip 25LC1024](http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en520389) CMOS serial EEPROM instead of DataFlash
112 * [Microchip MCP9700A](http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en027103) discrete temperature sensor
113 * used 1000uF electrolytic capacitor charged to 5V for pyro supply
114 * two LEDs instead of one attached to CPU
116 The elimination of the discrete temperature sensor and second LED were
117 necessary to support the companion board interface added in v0.2.
119 ## [Production History](../production) ##
121 ## [Flight Logs](flightlogs) ##
125 * The CC1111F32 is a 36-pin QFN package, which necessitates reflow
126 soldering. Since we needed to reflow solder anyway, and because TI used
127 them in their reference design, we went a little crazy and used 0402
128 passive parts everywhere. That means working under a microscope to
129 place parts! Without an inspection microscope, loading and testing these
130 boards might be impossible.
132 * The addition of on-board GPS in v0.2 means that the total power consumption
133 can exceed the rate at which we draw power from the USB interface,
134 particularly when the GPS is in cold start mode. This means a battery must
135 be attached during operation, and also that the battery will only charge
136 effectively from USB when the board is turned off.
138 * The v0.1 artwork had three issues, two of which required physical rework
139 on each board. All of these issues were fixed in v0.2.
141 * The USB connector footprint was placed wrong, so that the
142 connector hung out over the edge of the board instead of being
144 * We needed chip select on the SPI memory. To fix that, we gave up the
145 ability to put the accelerometer into self-test mode and used that
146 GPIO line to pull chip select on the memory, which required two
147 cuts and two jumpers.
148 * The igniter sense circuits each needed a second resistor to
149 complete the voltage divider so our 3.3V CPU ADC could read the
150 5V ejection voltage. This was fixed by changing two resistor
151 values, and tacking two additional resistors onto the board
152 with jumpers to ground.
156 The hardware design current gEDA files are available from
157 [git.gag.com](http://git.gag.com) in the project
158 [hw/telemetrum](http://git.gag.com/?p=hw/telemetrum;a=summary).
160 Work on the next version proceeds on the master branch, with occasional
161 temporary branches created when Bdale is making some major / speculative
162 change. The 'v0.2' and 'v0.1' branches document what we're actually flying
163 right now on the two respective PCB revisions. The 'ground' branch has a
164 cut-down schematic used to generate the BOM for partially loading v0.1 boards
165 to used on the ground. We call the on-the-ground version 'TeleDongle'.
167 For those who don't have ready access to the gEDA suite, here are pdf snapshots
168 of files in more easily readable form.
170 * These are from the v0.2 branch:
171 * [schematic](v0.2/telemetrum.pdf)
172 * [pcb artwork](v0.2/telemetrum.pcb.pdf)
173 * [bill of materials](v0.2/partslist.csv)
174 * These are as of the working-v0.1 tag:
175 * [schematic](v0.1/telemetrum.pdf)
176 * [pcb artwork](v0.1/telemetrum.pcb.pdf)
177 * [bill of materials](v0.1/telemetrum.bom)
179 Our [AltOS](../AltOS) firmware works well enough that we now routinely fly
180 TeleMetrum with no backup. Rockets with v0.1 boards have exceeded 50g
181 acceleration, been above Mach 1, and reached altitudes greater
182 than 12k feet AGL with great results. Keith's ground station program
183 called ao-view logs telemetry to disk, displays current and max values for
184 key parameters during flight, and even includes voice synthesis
185 during the flight so that our eyes can stay on the rockets! We have post
186 flight analysis software that makes it easy to extract data from the board,
187 analyze it, and even generate KML files for viewing flights in GoogleEarth!
188 More details on the software, including full source code and pre-built packages
189 can be found on the [AltOS](../AltOS) page on this site.
193 As of early March 2010, three prototypes of v0.2 exist and have flown with
194 great success. We will initiate a production run shortly with the goal of
195 making TeleMetrum available in assembled and tested form to others in the
196 rocketry hobby in time for the 2010 flying season.
198 Because we understand that not everyone uses Linux, we are investigating
199 the best way to make a cross-platform ground station program for use with
200 [AltOS](../AltOS), perhaps in Java...