- More information on analog inputs: https://learn.sparkfun.com/tutorials/analog-to-digital-conversion
- More information on SPI: https://learn.sparkfun.com/tutorials/serial-peripheral-interface-spi
- More information on I2C: https://learn.sparkfun.com/tutorials/i2c
- More information on using SPI and I2C with the Pi: https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorial