Design Decisions - Pedal
- Aashmika Mali
Pedal Board
The Driver Controls pedal interface is responsible for measuring the accelerator, brake pedal, and potentially steering angle through analog measurements. The accelerator pedal we used on MSXII was taken off a Chevrolet Malibu from UWAFT, and has 2 potentiometers built in for redundancy purposes. The board uses the external 12V and the 3V3 regulated from the controller board to power the op-amps for filtering, to be applied across the potentiometers and on the LDO. The 3.0V from the LDO is used to power the on-board ADC taking in the analog inputs coming from the accelerator, brakes and steering angle potentiometers. It uses I2C to communicate with the controller board.
Due to the noise present in the car from the motors and other communication devices, an active low pass filtration system was implemented on the analog inputs from the various potentiometers. The type of filtration uses passive RC filtering with a non-inverting amplifier providing a gain of 1. The RC filter provides a frequency cutoff, while the op-amp acts like a buffer and isolates Vout from the filtration. (see figure below)
