Td5 Datalogger Reboot

Monday, March 28, 2016 - 18:00

After a long hiatus I've been working on getting the Td5 Data Logger (aka Raijin Project) up and running.

The low level connection management code has been rewritten so it's a lot more robust. One of the big improvements is that it now uses the 5ms minimum inter byte timing specified by ISO14230 - in practice it's actually between 4.25 and 4.75ms. My theory is this timing allows the ECU more time to handle core processes so should help prevent dropped communications sessions under load. It's still missing error handling and recovery but otherwise working well.

The point to point wired board I've been using for development was a bit impractical for in-car testing, so I've had a piggy back board made up which should make it slightly easier to work on. The board is designed to plug on to a Fubarino SD development board, and has a ISO9141 interface chip, k-type thermocouple interface, 5V voltage regulator running off the OBDII port supply, a 5 way tact switch, and a connector for a small 0.96" OLED. The whole thing is about 25mm by 75mm.

I got notification today that the test boards have finally been shipped, a week later than the original estimated shipping date. I'll be interested to see how they turn out as this was the first time I've used Eagle to design a board and the first time I've had one of my own designs fabricated.