AltOS 1.3.1 — Bug fixes and improved APRS support

Bdale and I are pleased to announce the release of AltOS version 1.3.1.

AltOS is the core of the software for all of the Altus Metrum products. It consists of firmware for our cc1111, STM32L151, LPC11U14 and ATtiny85 based electronics and Java-based ground station software.

This is a minor release of AltOS, including bug fixes for TeleMega, TeleMetrum v2.0 and AltosUI .

AltOS Firmware — Antenna down fixed and APRS improved

Firmware version 1.3 has a bug in the support for operating the flight computer with the antenna facing downwards; the accelerometer calibration data would be incorrect. Furthermore, the accelerometer self-test routine would be confused if the flight computer were moved in the first second after power on. The firmware now simply re-tries the self-test several times.

I went out and bought a "real" APRS radio, the Yaesu FT1D to replace my venerable VX 7R. With this in hand, I changed our APRS support to use the compressed position format, which takes fewer bytes to send, offers increased resolution and includes altitude data. I took the altitude data out of the comment field and replaced that with battery and igniter voltages. This makes APRS reasonably useful in pad mode to monitor the state of the flight computer before boost.

Anyone with a TeleMega should update to the new firmware eventually, although there aren't any critical bug fixes here, unless you're trying to operate the device with the antenna pointing downwards.

AltosUI — TeleMega support and offline map loading improved.

I added all of the new TeleMega sensor data as possible elements in the graph. This lets you see roll rates and horizontal acceleration values for the whole flight. The 'Fire Igniter' dialog now lists all of the TeleMega extra pyro channels so you can play with those on the ground as well.

Our offline satellite images are downloaded from Google, but they restrict us to reading 50 images per minute. When we tried to download a 9x9 grid of images to save for later use on the flight line, Google would stop feeding us maps after the first 50. You'd have to poke the button a second time to try and fill in the missing images. We fixed this by just limiting how fast we load maps, and now we can reliably load an 11x11 grid of images.

Of course, there are also a few minor bug fixes, so it's probably worth updating even if the above issues don't affect you.