On Thu, 28 Jul 2011 14:07:01 -0700 Keith Packard <[email protected]> wrote:
> On Thu, 28 Jul 2011 13:16:20 -0700, DK Duncan > <[email protected]> wrote: > > > How difficult would it be to modify the firmware to allow antenna > > down orientations? > > I suspect the easiest way to make that work would be to hack the ADC > code to just flip the data around as it's coming out of the > sensor. There are lots of assumptions in the flight code about the > sign of acceleration changes and while possible to fix those, that > seems a bit more error prone. I made two changes to 0.9.4.3. I bumped AO_MAX_VERSION to 9 in ao.h to allow the inclusion of an additional identifier to the version string and made this change to ao_sample.c: ao_sample(void) { ... #if HAS_ACCEL ao_sample_accel = 0x7fff - ao_adc->accel; According to the comments if I understand them correctly, the ADC is programmed to 11 bits resolution and the results are shifted to the MSB of the word. The range is 0 - 32767. Upon recalibration I get values as follows: > c s Config version: 1.4 Main deploy: 200 meters (656 feet) Apogee delay: 1 seconds Radio channel: 1 (434.650MHz) Callsign: "k7dkd" Accel cal +1g: 8452 -1g: 8719 Radio cal: 1186652 Max flight log: 192 kB > v manufacturer altusmetrum.org product TeleMetrum-v1.1 serial-number 331 software-version 0.9.4.3i It enters pad mode correctly. This is the other telemetrum with stock firmware: > c s Config version: 1.4 Main deploy: 250 meters (820 feet) Apogee delay: 0 seconds Radio channel: 0 (434.550MHz) Callsign: "k7dkd" Accel cal +1g: 8092 -1g: 8366 Radio cal: 1186650 Max flight log: 192 kB > v manufacturer altusmetrum.org product TeleMetrum-v1.1 serial-number 267 software-version 0.9 Does all this seem sane to you? -- ~Don ------------ _______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum
