J2534 | Arduino

An Arduino runs a single void loop() .

But you can use an Arduino to —the very protocols J2534 wraps in software.

Across the room, on a breadboard covered in colorful jumper wires, sits an . It costs $25. It runs at 16 MHz. It blinks an LED with cheerful simplicity. j2534 arduino

J2534 devices are sophisticated. They contain high-speed microcontrollers, large buffers, and precise timing circuits. They cost hundreds of dollars.

CAN ID: 0x7E8 Data: 06 41 02 01 1A 2B 3C 00 An Arduino runs a single void loop()

And that little 16 MHz chip? It turns your garage into a laboratory.

if (CAN0.readMsgBuf(&canId, &len, buf) == CAN_OK) { Serial.print("CAN ID: 0x"); Serial.print(canId, HEX); Serial.print(" Data: "); for(int i=0; i<len; i++) { Serial.print(buf[i], HEX); Serial.print(" "); } Serial.println(); } } It costs $25

When Alex connects this Arduino to the OBD-II port of a car and sends a "Read VIN" request from a genuine J2534 tool on the laptop, the Arduino prints:

void setup() { Serial.begin(115200); CAN0.begin(MCP_ANY, CAN_500KBPS, MCP_8MHZ); CAN0.setMode(MCP_NORMAL); }

Now the hardware is ready. But the software is where the story gets interesting. A J2534 device responds to specific API calls: PassThruOpen() , PassThruConnect() , PassThruReadMsgs() . These are Windows DLL functions.