Wiring and Components - Week 5 & 6
After racking my brain trying to figure out how to wire the adaptive brake lights so that if the Arduino circuit fails, the brake lights will still work. I was toying with the idea of adding a resistor circuit which is activated by the Arduino and draws current from the lights to turn them off. However, there is a much simpler solution which uses a normally closed relay which will be switched into the off position to break the circuit. This will be done by the Arduino Uno and an NPN transistor. Below is a rough wiring diagram to display the idea.
The components we will be using are:
Sensor - 3-Axis accelerometer module for Arduino
Though we only require one axis for deceleration we will be using this sensor because its compatible with the Arduino and it is readily available.
Control Circuit - Arduino UNO, BD139 NPN transistor with a resistor added to the base to control voltage and a normally closed relay with a diode for protection.
Output Circuit - We will be using the existing brake light circuit which consists of the switch at the pedal and the lights.