Re: Transmitter update

Jared Smith

I now have the payload programmed. I have much testing to do and need to try to optimize the memory a bit (I'm at 70% dynamic memory), but it seems to be working correctly.

Here's an overview of what happens after adequate power is on-board:
  1. Program initiates and makes connection to clock generator and GPS
  2. GPS is programmed (high power mode, high altitude mode, correct NMEA sentences defined, etc.)
  3. Wait for GPS fix (around 3 minutes cold start, a few seconds warm start).
  4. Upon GPS fix, set Arduino clock to GPS time. Turn on LED (indicates GPS fix).
  5. Get lat/lon/altitude. Encode telemetry and temperature. All are stored to variables.
  6. GPS is set to low power mode.
  7. If minute is :00, :10, :20, etc., initiate standard transmission. LED flashes during transmissions.
  8. If :04, :14, :24, etc., initiate telemetry transmission. Then loop back to #1.
I wired up the solar array today and will check voltage tomorrow (a nice sunny day!).

I then need to figure out how to get all of this together in a way that it will hang from a tether with the solar panels pointing up, while also being VERY lightweight. I'd be happy to hear ideas.

One thing I'm not sure of is orientation of the GPS antenna. It's a very short antenna. I'm not sure if it should optimally point up or horizontally. Anyone know?

Gary, do you have your components? Let me know if you'd like to coordinate to get stuff from me. And I can send you Arduino sketches any time.



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