3 This is the design that started it all! Bdale got frustrated with existing
4 commercial altimeters and decided to build his own. This project was
5 presented in talks at LCA, SCALE, OLS, and Debconf in 2008.
8 Here are photos of the front and back sides of the version 0.1 prototype PCB.
10 <a href="hpim2581.jpg"> <img src="hpim2581-thumb.jpg"></a>
11 <a href="hpim2582.jpg"> <img src="hpim2582-thumb.jpg"></a>
17 * Recording altimeter for model rocketry
18 * Supports dual deployment (can fire 2 ejection charges)
19 * Primary operations based on pressure sensor
20 * 3-axis accelerometer
22 * 2 serial ports for attachment of GPS and RF link modules
23 * USB for data recovery and post-flight power source
24 * Flexible battery choices
25 * Designed to fit 24mm airframe tube
27 ### Developer View ###
29 * NXP LPC-2148 Processor (ARM7TDMI-S)
30 ** 512k Flash memory, 32k RAM
31 ** USB plus lots of analog, digital, and serial I/O
35 In addition to the various "oopses" that were found and fixed during initial
36 turn-on of this board, several issues contributed to the decision to shelve
39 * lots of work went in to trying to make the board fit in a 24mm airframe,
40 but the resulting design with battery is really too heavy for such a small
43 * the 3-axis accelerometer has a max scale of +/- 6g. This is insufficient
44 for characterizing the kinds of motors that we're playing with now.
46 * while using a gcc-based toolchain to cross-develop for the ARM7 core works
47 reasonably well, it's a heavy toolchain to build and maintain, and the
48 processor really is serious overkill for the task at hand.
52 The version 0.1 design had enough issues that Bdale decided not to publish
53 it. Work on an 0.2 revision is mostly complete at the schematic level, and
54 some printed circuit board artwork updates were made, but a second run of
55 boards was never attempted. This design is now mostly of historical interest.