The Circuit

The circuit will be built across the two internal sections of SelfieBot. At the heart of the circuit is the Pi Cobbler, which routes all the pins of the Raspberry Pi neatly to a perma proto board. Here is a rundown of the Cobbler's connections:

Thermal Printer

RX to GPIO 14, and related ground to GND rail

Arcade Button

Data pin to GPIO 17, power to 5v rail, ground to GND rail

Accelerometer

SCL to GPIO 3, SDA to GPIO 2, VIN to 3V rail

Amplifier

A- & A+ to audio out on Pi (see Assembly for location on back of Pi) Power to 5v rail, GND to ground rail.

Power Circuit

Power and ground from the battery are split: one set of power and ground goes directly to the thermal printer, the other set goes to the input side of the UBEC step-down converter.

Power and ground from the output side of the UBEC goes to power the Raspberry Pi via the micro USB port.

You'll also connect power and ground from the Raspberry Pi GPIO to the perma proto board.

Other Connections

The display plugs into the HDMI port on the Raspberry Pi, and is powered by USB from the Pi. 

The speaker wires connect to the screw terminals on the amplifier.

This guide was first published on Dec 10, 2017. It was last updated on Dec 10, 2017. This page (The Circuit) was last updated on Nov 06, 2019.