Radio-Rocket video

Radio Rocket V3 Electronics Payload

by Vance Martin

Radio Rocket V3 Electronics Payload

I suppose it’s time to do an update on the status of the electronics payload for version 3 of the rocket, to bring all 7 of my loyal blog readers up to speed :-) I share a bunch of ad hoc stuff on Mastodon so if you follow the rocket there, you’ve seen some of this info already.

I shared in my last post that one of the major changes for version 3 was the decision to move away from ‘breakout boards glued and screwed to a piece of wood’ construction, and to instead do custom designed PCB carriers, so that the sled would also be the electronics bus, to replace all the wires.

For me, the first step of doing this was learning how to use KiCad, but after a week or so I was zipping around in there, and eventually ordered up my first batch of boards:

As expected, I did find some bugs, problems, and things to redesign from the first batch of boards, that I fixed up for bench testing by cutting traces and adding jumpers, and things like that:

I also ended up switching to a shorter battery type (switched from using 18650 to 18350), so that I could shorten up the battery carrier sled, in order to standardize the length of the rectangular carrier boards:

After doing the redesign, I ordered up another batch of boards, which are now the versions currently in use. This new selection of boards is:

  • Circular boards, starting at the top left and going clockwise:
    • BT-60 (41.5mm) Tube Size Spacer / blank adapter
    • Carrier for ‘6 pin’ Adafruit breakout boards (like the LSM6DSOX 6 DoF Accel/Gyro and ADXL375 High G Accelerometer)
    • Carrier for ‘7 pin’ Adafruit breakout boards (like the BME 680 Temp/Humid/Pressure/Gas board)
    • Antenna mount and Diplexer board (to allow VHF aprs & UHF LoRa to share an antenna)
    • ‘Trigger’ board (mosfet based trigger to fire ignitors, or turn other accessories on and off)
    • ‘Perf Board’ which allows me to do some experimentation of small circuits
    • 38mm Tube Size Spacer / blank Adapter
  • Rectangular boards, left to right:

And after flowing some solder to start assembling things, it’s coming together nicely! I still have a couple items to do yet on the sled (adding a couple modules and sub-boards that are still on the way) but it’s technically ‘working’ now, and fits nicely inside the payload bay of the under-construction rocket!