July 09, 2020, 11:07:14 AM

Author Topic: Getting started with CANBUS?  (Read 334 times)

Offline wompa164

Getting started with CANBUS?
« on: June 17, 2020, 07:02:12 PM »
Hey all,

It seems like an increasing amount of accessories are starting to utilize CAN, and as a computer guy it seems like a logical progression for our vehicles.

I am trying to work on an issue with my MSEL battery isolator. In summary, when the battery is connected the device has a configurable output wire. In the default configuration, this wire provides +12v battery power to the relay coil (#85) and allows #87/#30 to pass power for all of my switched 12v accessories (including ECU), so that if I have to use the battery kill switch, the ECU will die and stop the engine from running per most racing body standards.

I am having a small issue where if I forget to use the drivers kill switch, the relay stays active all the time (~100mA) and drawing down my battery. I was reading the documentation for the device and apparently this behavior can be changed:



I was thinking about changing it to configuration #6, whereby it provides ground to pin #86 and I can just pull switched power for #85 from #87/#30, so that the relay is only active when getting switched power.

However I have literally zero experience dealing with CAN, how difficult would it be to get started with trying to send a CAN message?



Are there cheapo devices that can do this relatively easily? Unfortunately my Holley Terminator uses some proprietary version of CAN which is unfortunately, I would love to start dipping my feet in getting different parts of the car talking to each other :punch:

As an aside I found this when researching relay box solutions for my chassis rewire, maybe something to explore in the years ahead, though I would probably sooner do a Motec PDM30: https://www.waytekwire.com/item/46066/EATON-31M-000-2-Mulitplex-Vehicle-Electrical/

Cheers all,

Offline digitalsolo

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Re: Getting started with CANBUS?
« Reply #1 on: June 17, 2020, 11:38:56 PM »
Oh boy, haha.

So you can do the CAN message with an Arduino pretty easy.    USB car charger for power and a few wires to a CAN transceiver.   I have code written I can point you to that Iíve used for AndrewB to setup CAN messages to a Prius electronic power steering, should work with some tweaking.

I have a couple of those CAN MVECs, they are a pain in the ass.    I had planned to use them and ended up with an ECUMaster PDU, I got tired of fighting with the Eaton stuff, their support sucked.

Iím happy to help wherever I can, no pun intended.   Iíve got a couple hundred hours poking at CANbus stuff.
Blake MF'ing McBride
1988 Mazda RX7 - Turbo LS1/T56/ProEFI/8.8/Not Slow...   sold.
1965 Mustang Coupe - TT Coyote, TR6060, modern brakes/suspension...  project car
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Online Exidous

Re: Getting started with CANBUS?
« Reply #2 on: June 18, 2020, 01:00:49 AM »
Blake,

You should hold a 101 course. Or at least point us towards one. I understand the basics but really need to learn more. I managed to get the AEM WB and Perfect Tuning gauge to work despite being on different protocols. Needed to get the 11bit firmware from the maker of the gauge. 29bit was it's standard.
94 BB Sleeved gen IV LS7, MS3ProU with TC, RONIN 8.8 and LT's with custom 3.5"single to VAREX muffler.

Offline wompa164

Re: Getting started with CANBUS?
« Reply #3 on: June 18, 2020, 11:31:27 AM »
Oh boy, haha.

So you can do the CAN message with an Arduino pretty easy.    USB car charger for power and a few wires to a CAN transceiver.   I have code written I can point you to that Iíve used for AndrewB to setup CAN messages to a Prius electronic power steering, should work with some tweaking.

I have a couple of those CAN MVECs, they are a pain in the ass.    I had planned to use them and ended up with an ECUMaster PDU, I got tired of fighting with the Eaton stuff, their support sucked.

Iím happy to help wherever I can, no pun intended.   Iíve got a couple hundred hours poking at CANbus stuff.

Good to know! I actually heard back from the reseller (Racespec) and they said if I ship them the unit, they'll reprogram it free of charge so I might just do that.

However I'm still interested.. do you have the code stored on Github or somewhere?