Bratton Camera - Setup

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I found wiring up the FONA to be incredibly difficult.

  • FONA GND to Raspberry Pi ground.
  • FONA Vio to Raspberry Pi 3.3 volt power.
  • Second 3.7v Battery Ground to FONA Key.
  • FONA TX to Raspberry Pi RXD.
  • FONA RX to Raspberry Pi TXD.
  • Second 3.7v Battery Power to Power
    This is the jack that supplies power to the fona, not a pin.
  • Second 3.7v Battery Ground to FONA Key to Ground
    This is the jack that supplies power to the fona, not a pin.
Because the board is so small I soldered extra long pins to the holes to make the wiring process a bit smoother. I was so afraid of shorting/melting the board that I spent a lo of time with the multimeter checking and rechecking connections. Yet inspite of being so careful I ended up breaking the power input to the FONA. For some reason the leads for the power and ground of the FONA are incredibly brittle. An accidental tug was all that was needed to completely remove them from the board. To fix this problem I ended up completely removing the power jack with some needle nosed pliers and an exacto knife. I then soldered on some extra long pins to where the GRND and PWR used to be. It was terrifying.

My main problem with regards to wiring up the circuit board was that it took me a long time to figure out that I needed a second battery. I am still unsure why. Though the board has VIO and GRND holes that I connected to the 3.3V and GRND of my PI, I ALSO needed to power the board through the jack that I broke. Why?

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Once the FONA is wired up to the PI you need to do quite a bit to ensure that it can speak to the PI. On the Raspberry Pi you need to disable the kernel's use of the hardware serial connection. On older versions of Raspian(The Pi's operating system) you could use a library to automatically stop the bootup process from writing to the serial port by adding lines in the /etc/inittab library. However this is impossible on the newer version of Raspian. To do this I had to do some serious digging. The answer is this line of code:

sudo systemctl stop serial-getty@ttyAMA0.service

After I did this, I essentially followed this tutorial.

Overall the setup took me about 7 hours, which is 5 hours more than I thought it would.

Up Next, building a node service on Heroku that listens for tweets, and can recieve and store photos.

Written on November 28, 2015