I have mentioned before that the controller for my MicroQuad project doubles as the controller for my high altitude balloon project. Since I have set a launch date for early September, I have decided to put aside the quadcopter project for the next few weeks and focus on the launch. That said, I have been revising my PCB and finally received some new ESCs and props from HobbyKing, some 2.5x1 props and 4 more ESCs to replace the hokey ones I've got. Changes to the PCB include:
- Removal of the TPS61200 boost converter. It never played nice with my other components
- Removal of the USB hosting port. I decided to use a very small bluetooth module instead
- Addition of the TPS73233 ultra low dropout linear regulator. 3.3v, 250ma, and 40mv of dropout
- Addition of the OSHW logo! I'm going to get these files on GitHub soon.
- Fixing the MPU-6050 layout. I had a capacitor on the charge pump that wasn't working correctly and some mixed up pins.
- Fixed/new GPS chip antenna layout. Running antenna feed lines through vias isn't a good idea. I decided to mount the antenna on the bottom of the PCB, as if it was radiating into the ground. But, I cut a slot underneath it and mount the radiation pattern showing through the slot and up towards the sky. This should give a better signal.
When i order Rev 2.1 I also want to get it from Advanced Circuits instead of SeeedStudio. Hopefully it will take less time to get the boards back. Also, I'm waiting on some 50 ohm coax cable I should get on Monday, there will be a big post about that!