Custom Rev Limiter Warning System and Gear Position Indicator
I’ve had my Toyota GT86 for a while, and I absolutely loved its built-in rev limiter warning and the thrill of flooring it until an elderly lady cancelled my insurance. However, I was fortunate enough to drive a BMW 430d M Sport courtesy of my insurance company for a few months. Currently, I’m behind the wheel of a 2006 Honda Civic Type-S GT hatchback, and I’m really missing that warning (and the rest of the 86’s goodies).
By leveraging Arduino and an affordable MCP2515 module, I successfully sniffed the communication between the ELM327 diagnostic tool and my Civic’s OBD-II port. I discovered that the CAN bus operates at a speed of 500Kbps, transmitting a multitude of standard 11-bit ID CAN messages. By sending the “010c” command to the ELM327 to request engine RPM data, I observed it sending extended 29-bit CAN messages with an ID of 0x18DB33F1, followed by a response ID of 0x18DAF110. (I won’t delve into the intricacies of OBD-II protocol’s physical and functional addressing here, but searching for these two hex numbers online will yield some fascinating results.) Excellent!…