Specifically designed for a Nissan Micra K12 but can be adapted to other cars with existing PCB and firmware changes. DEVICE UNDER DEVELOPMENT. DO NOT USE IT IN A CAR.
The goal of this project is to design an aftermarket KIT that is able to hold the specified speed of a car.
Inputs
- Abs speed sensor signal for measuring speed
- Brake light signal to detect when brake pedal is pressed
- Actual accelerator pedal signal
- Various Buttons for controlling the Cruise Control
Outputs
- The accelerator pedal signal that is routed to the car ECU
- Various indicator lights
How it works:
- If the Cruise Control is OFF, the actual accelerator pedal signal is routed to the ECU without the intervention of the KIT.
- If the Cruise Control is ON, the Arduino reads the speed of the vehicle through the Speed Sensors and generates the correct pedal signal so that the vehicle maintains set speed. The generated (fake) pedal signal is then routed to the ECU.
- A MUX is used that outputs either the real accelerator pedal signal (when Cruise Control is disabled) or the (fake) signal of the Arduino (if Cruise Control is enabled).
- Two relays connected in series act as a MUX while also providing redundancy. In case one relay is stuck the real accelerator pedal will always be routed to the output.
- The brake pedal deactivates the Cruise Control and immediately (via hardware logic) changes the Select signal of the MUX so that the output changes to the real accelerator pedal. The system will always switch the output to the real accelerator pedal even if the Arduino is frozen.
I am currently testing the board, the functionality works as expected with the prototypes. Never use it in car since it is not 100% tested and I can not guarantee that it works flawlessly. Severe injury can be made. More testing has to be done. Software will be the next step.
Copyright 2021 Lolis Ilias
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