Reverse Engineering & Upgrading Car Parking Sensors

This instructable shows you to understand reverse engineering, analysing data and developing new product with these information.

In order to understand working principle of parking sensor, I needed to specify correct data pin. Then I measured voltage levels with multimeter and saw that there is 3-pin connection between Display unit and main unit, 4th cable is not working which are:

• GND - BLACK
• VCC - RED
• DATA - WHITE

I connected black one with ground and white one to Channel 1 of logic analyser.

After working for a week on understanding the meaning of bits, I found out that the first byte represents distance in a form of inverse of each bit, following 4 bits are sensor id and last 4 bits are stop bits.

I measured the durations of Start Signal, logical 1 and logical 0 in micro seconds. It helped me to split them into these three forms. Also I connected the data bus to arduino nano interrupt pin (D2).

After I extracted the data, I wrote a program that can sends command to serial mp3 player via uart. I used softwareserial D8 D9 on arduino.

Arduino Nano link is here

Mp3 module link is here

Arduino Nano Code is in the attachment

• 01\001.mp3 --> its welcome message

when you switch your car into reverse gear, you will meet with this.

the other files are like :

• 01\002.mp3 --> 10-20 cm.
• 01\003.mp3 --> 20-30 cm.
• 01\004.mp3 --> 30-40 cm.
• 01\005.mp3 --> 40-50 cm.
• 01\006.mp3 --> 50-60 cm.
• ...
• .....

I used www.easyeda.com to design my circuit and produce its pcb.

you can access my project from here

In order to use the same connectors of parking sensor I ordered 2.5 4-pin 3S1P Balance Charger Silicon Cable Wire JST XH Connector Adapter Plug from this link and a speaker from this link

It works perfectly! :)