Managed to get the battery pack working with my Pro Mini and UBlox GPS…
I was concerned I’d have to add a voltage regulator to even out the battery supply, but luckily the Pro Mini from Sparkfun has a regulator on board!
Now I’ve simply connected my two power pins to the GND and RAW pins on the mini. See below:-
As you can see I’ve also got my Ublox GPS package from Airbot plugged in as before.
The difference now are the extra pins – A4 and A5 – being split out on to the breadboard, and the VCC line being taken to both left-bottom rails.
This is for the I2C specification – I’m going to add two 2K2 Ohm pull-up resistors where the left hole is in the breadboard.
The I2C is for the HMC5883L magnetometer (3D compass) [PDF] which shares the Airbot provided board with the UBlox GPS.
This has all been powered successfully by the 2000mAh Li-ion battery from Sparkfun.
I’ll get the I2C compass working later. Right now I want to check I can get the LCD display working for debugging.
After that comes the radio! I’ll use the hardware serial for that, as I suspect the 3DR radio is a beast and will need this hardware support.
I’ll probably have to immediately put the radio in to a low power burst mode – the voltage regulator only supports up to 500mA, and I suspect I’ll draw close to that initially without power saving enabled.