4 brilliant students from the Grade 11 Computer Engineering Class were enlightned by the project requirements from Mr. Andrade. The students were to control the throttle using the computer. The students were also suggested to use the OBD2 Diagnostic Reader, which gave direct control to the ECU.
The following two weeks were spent in the car mulling over the logistics and practicals of the operation including evaluating the vehicle of the project; a "Brilliant Silver" 2009 Nissan Sentra with more than 120,000 Kilometers on the odometer, and a dead battery.
These two weeks were spent researching and trying to work through the OBD2 Port by trying to find software that will allow us to send information in addition to receive information, which we were able to derive using "Car Scanner ELM OBD2". We also experimented using other software but did not prove fruitful. We tested "EcuFlash", "MaxxECU MTune", and "ScanXL".
We realized that the OBD2 Scanner was a lost cause and that we would come back to it if we have time left over. Instead, we decided to disconnect the throttle and found out how it sent a signal to the ECU. We found a 6 pin pigtail connector that was responsible so we tried to send a signal using a multimeter at first, to no avail however. We then decided to call Nissan dealerships as well as OEM dealers around the area, (after colluding with around 15 different dealers) unfortunately due to the the pin being proprietary to Nissan, they were unable to help us, however we were able to get useful feedback on how they would tackle this.
After the Winter Break, we felt a fresh new wave of motivation alongside the appall of not finishing the project yet which was given months ago, leaving us only a couple weeks before the end of the semester and course. After recollecting our thoughts over the break, and concluding our research, we arrived at the predicament that the pigtail and trying to send a signal through it was a lost cause. We then decided to approach it through a rather simplified method where we bought a spare throttle pedal, and attached a servo motor to it, in coordination with an Arduino.
Reaching the final stretch of the project, when we attached a gear to the motor aimed to a gear attached to the throttle pedal, the gear was rendered static due to a lack of torque from the motor. In order to bypass this problem, we decided to use mechanical advantage to our advantage where we attached a small gear for the motor in conjunction with a larger gear for the pedal which gave us the necessary torque. The last step was to develop the software to control the Arduino. We created a Python Flask Webapp which utilized PyFormata in order to control the throttle via a command line-type interface. The entire codebase for this project can be found below.
Firmata Library: https://github.com/firmata/arduino#firmata-client-librariesArduino Connection Setup Code (Firmata) Arduino C++: https://github.com/firmata/arduino/blob/main/examples/StandardFirmata/StandardFirmata.inoConstant Motor Oscillation Code: https://github.com/SarveshwarSenthilKumar/Auto-Throttle-Backend-Codebase/blob/main/oscillatingMotor.inoConstant Motor Oscillation Code (Python): https://github.com/SarveshwarSenthilKumar/Auto-Throttle-Backend-Codebase/blob/main/alwaysSpin.pyManual Motor Adjustment Code (Python): https://github.com/SarveshwarSenthilKumar/Auto-Throttle-Backend-Codebase/blob/main/motor.pyAuto-Throttle Control Webapp Front-End (HTML & CSS): https://github.com/SarveshwarSenthilKumar/Auto-Throttle-Backend-Codebase/tree/main/templatesAuto-Throttle Control Webapp Back-End (Flask-Python): https://github.com/SarveshwarSenthilKumar/Auto-Throttle-Backend-Codebase/blob/main/app.pyrev xsleep xangletest x-yreset x
