Hi Sterretje & J-M-L
You are quite right, it is missing the checksum. I'm using a hardware interpreter chip called ELM325 that sits between the engine ECU and the Arduino. This manages (and optionally filters) the stream of data from the ECU and by default strips out the checksum and the MID codes before passing onto the serial input of the Arduinno. From their datasheet (attached) I understand that the ELM325 prints ascii rather than binary as they demonstrate the chip using a standard hyper terminal. To be honest I've not connect this to my engine yet so I don't have a real stream of data. The example I gave was from their datasheet. I suspect it may be possible to eliminate the ELM325 and read the raw data directly - but I wanted to break the project down into segments that I could prove and develop individually. Step 1) Connect ELM325 to engine with a laptop and confirm data/proof of concept/capture sample data. Step 2) Use sample data to emulate engine and develop Arduino code to decipher the data (this post). Step 3) Develop can-bus link to transmit engine data to NEMA2000 to display on MFD (hopefully testing this weekend).
Thanks J-M-L I've been reading the Serial Input Basics today and picked up some great pointers from that. I'll have a crack at Strtok and atoi examples and surely fail - but it's fun!!
Thank you very much for your interest and feedback, really appreciated.
Cheers
Tim
ELM325DS.pdf (172 KB)