Part 2. Wiring
Make sure that everything is powered down and unplugged before you start connecting anything!
As I mentioned earlier, my Pi Zero has a pin header soldered to it, and the Fona comes with one, so we'll be using Female-Female tie lines.
- Connect the Fona's GND to the Zero's GND (Row 2, Pin 3) AND the Fona's Key (I ended up soldering 3 tie lines together to do this, but you can prototype with a breadboard)
- Connect the Fona's Vio to the Zero's 3.3V power (Row 1, Pin 1)
- Connect the Fona's TX to the Zero's RX (Row 2, Pin 5)
- Connect the Fona's RX to the Zero's TX (Row 2, Pin 4)
- Connect the cellular antenna now - it is labeled "GSM ANT" on the Fona
- Connect the Fona and Pi with the micro-USB to USB cable
- Connect the Lipoly battery to the Fona
Power on the Pi and the Fona should light up, too, with a solid blue LED and slow blinking red LED.