ECU data from pre-canbus Subaru

finse · Post by **finse** » Tue Oct 13, 2015 6:40 am

Over the last couple of years I have slowly been adding on to my RaceCapture setup. Previously, to capture ECU data I was utilizing the logging feature on my Cobb Accessport. However, I was unsatified with the process to get my setup logging for track time. Not to mention lining up the RCP and AP data was very difficult and time consuming.

I was determined to replace the AP with an interface that translated ECU data into CAN messages for processing by the RCP. I really like Arduinos (previously wrote code for a Yun to allow my RaceCapture to start/stop recording on my GoPros). I decided to implement this on arduino.

Pre-Canbus / OBII equipped Subaru's use a version of iso 9141-2 with a protocal layer called "Subaru Select Monitor" or SSM for short. It runs on a half duplex serial connection with a baud rate of 4800. In a nutshell, it's your basic call and response model. I found some previous work on clubwrx.net. The author had built an arduino based code scanner/gauge to replace his clock with. Further, the author was kind enough to post his design schematic and code.

I changed the way the code worked, but retained the portions of the code for reading/writing to the ECU. I added a CAN bus layer, a more track orientend request "string" and then tuned it until I got the refresh rate down to around 60 milliseconds.

I finally had a chance to test it out over this past weekend at an open lapping day, and overall I think it did fairly well. It's all posted on github. If this is something you have interest in pursuing, I am happy to answer any of your questions.

Open lapping day: https://www.youtube.com/watch?v=3QWjXjI28gE
Github: https://github.com/rpkish/Subduino-SSM
Original Project: http://www.clubwrx.net/forums/tutorials ... duino.html

Post by **brentp** » Mon Oct 19, 2015 5:34 pm

This is fantastic! Thank for for sharing this project. I think we'll be chatting more about this.

Sgt.Gator · Post by **Sgt.Gator** » Thu Sep 15, 2016 5:14 pm

Any update on getting the Subaru SSM data into Racecapture?

There is another Android app that get's it all, BtSsm. It's widely used in the Subaru Legacy community. However it has no racer G-force data, just all the Subaru engine data. And now the automatic trans data too off the TCU.

http://www.btssm.com

There's a very long thread here: http://legacygt.com/forums/showthread.p ... 29709.html

I've considered running BtSsm in the background or a split screen on a tablet while using RC for the driver data but not sure how all that would work.

finse · Post by **finse** » Thu Sep 15, 2016 6:08 pm

Sgt.Gator wrote:Any update on getting the Subaru SSM data into Racecapture?.

Hello fellow Legacy driver! Subaru SSM support was something I built and contributed to the community, it's not actually supported by the good people at ASL, but I am happy to try an help if you have questions. That said, I've been using my "subduino" for about a year now, it works pretty well.

Sgt.Gator wrote: There is another Android app that get's it all, BtSsm. It's widely used in the Subaru Legacy community. However it has no racer G-force data, just all the Subaru engine data. And now the automatic trans data too off the TCU.

http://www.btssm.com

There's a very long thread here: http://legacygt.com/forums/showthread.p ... 29709.html

I've considered running BtSsm in the background or a split screen on a tablet while using RC for the driver data but not sure how all that would work.

Previously, I used my AccessPort to log engine telemetry data and then manually merged the data after my sessions. This was pretty hard work, and error prone. It's the exact reason I developed the subduino. Using a BT app would present similar challenges for me, but our use cases my be different.

What year is your car? If I can, I'll help as much as I am able to.

Cheers,
Ryan