3 This is a recording dual-deploy altimeter for high power model rocketry
4 with integrated telemetry link.
6 <a href="loadedpair.jpg"> <img src="loadedpair-thumb.jpg"></a>
7 <a href="rawfront.jpg"> <img src="rawfront-thumb.jpg"></a>
8 <a href="rawback.jpg"> <img src="rawback-thumb.jpg"></a>
12 Bdale and Keith both own
13 [BeeLine](http://www.bigredbee.com/BeeLine.htm)
15 [Big Red Bee](http://www.bigredbee.com), and are pretty happy with them.
16 They use a PIC processor and a TI CC1050 transmitter chip, and
17 operate in the ham radio 70cm band.
19 One weekend while attending a conference together, we got to wondering if
20 we couldn't adapt one to use as a downlink for the
21 [AltusMetrum](../AltusMetrum/) altimeter board in addition to direction
22 finding after flight. That caused us to start thinking about other things
23 in the design we might want to tweak, and before long we were working on the
24 design of a new tracker board derived from the BeeLine design.
25 Another friend at the same conference showed us a board he was working on
26 using a different part in the same TI series, that integrated a transceiver
27 and CPU on the same chip.
28 It didn't take us long to realize that with such a part we could combine and
29 simplify things by building a new altimeter with integrated RF link!
35 * Recording altimeter for model rocketry
36 * Supports dual deployment (can fire 2 ejection charges)
37 * 70cm ham-band transceiver for telemetry downlink
38 * Primary operations based on pressure sensor
40 * 1-axis high-g accelerometer for motor characterization
41 * On-board non-volatile memory for flight data storage
42 * Serial port for attachment of GPS module
43 * USB for power, configuration, and data recovery
44 * Integrated support for LiPo rechargeable batteries
45 * Designed to fit 29mm airframe coupler tube
47 ### Developer View ###
49 * [TI CC1111F32](http://focus.ti.com/docs/prod/folders/print/cc1111f32.html) Low Power RF System-on-Chip
50 * Sub-1Ghz transceiver
55 * analog, digital, and serial I/O
56 * [Microchip 25LC1024](http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en520389) CMOS serial EEPROM
60 * [Freescale MP3H6115A](http://www.freescale.com/webapp/search.partparamdetail.framework?PART_NUMBER=MP3H6115A6U) pressure sensor
61 * [Freescale MMA2202EG](http://www.freescale.com/webapp/search.partparamdetail.framework?PART_NUMBER=MMA2202EG) 50g accelerometer. Can use 40-200g variants!
62 * [Microchip MCP9700A](http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en027103) temperature sensor
63 * Software Features (planned)
64 * Written mostly in C with some 8051 assembler
65 * Runs from on-chip flash, uses on-chip RAM, stores flight data to
67 * USB serial emulation for "console" interface
68 * USB mass storage emulation for data recovery
70 * [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
71 * [SDCC](http://sdcc.sourceforge.net/) compiler and source debugger
72 * [FreeRTOS](http://www.freertos.org/) kernel
74 * The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
75 * The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)
79 * The CC1111F32 is a 36-pin QFN package, which necessitates reflow
80 soldering. Since we needed to reflow solder anyway, and because TI used
81 them in their reference design, we went a little crazy and used 0402
82 passive parts everywhere. That means working under a microscope to
83 place parts! Without an inspection microscope, loading and testing these
84 boards might be impossible.
86 * The v0.1 artwork has two issues that require cuts and jumps. The first is
87 that we need chip select on the SPI memory. To fix that, we give up the
88 ability to put the accelerometer into self-test mode and use that GPIO line
89 to pull chip select on the memory. The second is that the igniter sense
90 circuits each need a second resistor to complete the voltage divider so our
91 3.3V CPU ADC can read the 5V ejection voltage. This is fixed by changing
92 two resistor values, and tacking two additional resistors onto the board
93 with jumpers to ground.
97 The hardware design current gEDA files are available from
98 [git.gag.com](http://git.gag.com).
100 Keith has working data collection firmware, however the firmware is under a
101 massive, rapid rewrite to eliminate FreeRTOS which is much more generalized
102 and capable than we need... and consuming more system resources than we
103 can tolerate. As soon as we're over this transition, the sourcecode to the
104 firmware and related tools will also be made available.
106 As of 11 April 2009, the first two boards are fully checked out, we have some
107 initial firmware capable of data logging ready, and as soon as we get a good
108 day to fly we hope to log our first flight data!