As is briefly touched on in the white-line sensor documentation, the LDRs exhibit a lower resistance when they see more light. Therefore, when used in a voltage divider circuit, an output voltage can be obtained that is proportional but opposite in sign to the amount of light incident. This means that the output voltage of the white-line sensors will be a variable voltage somewhere between supply voltage and . Analogue-Digital Conversion is required for the microcontroller to interpret these values, and the microcontroller we used, the Raspberry Pi Pico, features 26 GPIO pins with only 3 of which possessing ADC capabilities.
We needed to use 4 LDRs in our Micromouse to detect falling out of the combat ring in all four corners. This meant we needed more ADC pins than is actually present on the microcontroller, and as such we used the Adafruit ATtiny817 port expander, featuring 15 additional GPIO pins, with 9 of which having ADC capabilities. The seesaw was connected to the microcontroller using the I2C interface.
We decided to also connect the touch bars to the seesaw, due to their relative proximity compared to the microcontroller. This helped to reduce the number of wires vertically across the whole Micromouse.