Getting canbus instruments to work in a non canbus car?

[EddyP]

A lot of the modern cars these days are all canbus, especially with things such as the instruments.
I've seen some that look quite nice, for example late clio or lexus ones, and i'd love to try and make these work off a volvo t5 engine, non can bus, for a kit i'm building.

Anyone know if there's any way around it? i'm not that clued up on canbus things.

Thanks

[annodomini2]

EddyP said:

A lot of the modern cars these days are all canbus, especially with things such as the instruments.
I've seen some that look quite nice, for example late clio or lexus ones, and i'd love to try and make these work off a volvo t5 engine, non can bus, for a kit i'm building.

Anyone know if there's any way around it? i'm not that clued up on canbus things.

Thanks

Check wikipedia on Canbus and its basics.

There are 2 primary communication protocols in automotive, CANOpen and J1939.

The Clio is CANOpen, it is more than likely the Lexus will be also.

The main problem you face is modern car CANBus systems are configured to operate as an interoperating network with sensors being fitted to the various ECUs fitted to the car (most basic modern cars have around 14 ECU's, with high end stuff having around 60-70) and all those ECU's talking to each other to gather the information they require to operate.

With CANOpen you would first need something called the EDS or Electronic Data Sheet for each ECU which was fitted to the car (Something Renault and Lexus are more than likely unwilling to release)

These describe the messages transmitted and received by the ECU's on the bus.

When you have this information you would need to find some way of transmitting the required messages to the Dashboard unit.

Be that with an off the shelf box that supports this, which is probably unlikely.

Or something custom built, this can be done at home with say a CANBus based PLC ECU with enough I/O to read the signals from your engine and convert them into messages for the Dash, but again you need the EDS to produce the correct messages.

A more plausible solution may be a PLC based Display unit where you can draw the design for the dash board and have something truely unique. Although you would need to learn software to implement something like this.

Hope this information is of use.

[EddyP]

Thanks for the info, useful stuff.
I'v found some nice MK5 polo instruments now too, they're probably going to be just as complex tho to get working at a guess.

Do you know of any PLC type bits that would do the job?
I could put a screen into the dash and have it displayed as a type of HMI on there instead, we have these at work on control panels, but they're using industrial PLCs, i'll have a chat to the guy who designs them though, he might know of something.

Thanks.

[CLOG]

Hi there, if the speedo is not mechanically driven you might be able to use the signal straight from the wheel sensor or ABS ctrl unit (same signal)

[annodomini2]

CLOG said:

Hi there, if the speedo is not mechanically driven you might be able to use the signal straight from the wheel sensor or ABS ctrl unit (same signal)

The Clio dash acquires all of its information from the CAN-Bus not digital inputs or mechanical drive

[annodomini2]

EddyP said:

Thanks for the info, useful stuff.
I'v found some nice MK5 polo instruments now too, they're probably going to be just as complex tho to get working at a guess.

Do you know of any PLC type bits that would do the job?
I could put a screen into the dash and have it displayed as a type of HMI on there instead, we have these at work on control panels, but they're using industrial PLCs, i'll have a chat to the guy who designs them though, he might know of something.

Thanks.

There are a few companies I know of who make them and they are typically used for mobile machinery

suggestions:

IFM Electronic

EPEC

TTTech

They use something called CoDeSys which is a PLC programming standard.

There are others, but their units do support CAN.

[anonymous-user]

Here's how i'd do it:

1) chose a CAN dash from a car i could get access to (so if a polo unit, try to beg / borrow a whole working polo off a friend etc)

2) buy a CAN interface to USB adaptor (lots availible from peeps like Kvaser etc)

3) download a freebee CAN capture application (CANking, CANcapture etc)

4) in your borrowed car, splice (carefully!) into the CAN bus, only 2 wires to connect, and log what's going backwards and forwards, it should be possible with a little thought, to work out the main signals and their scaling (i.e. sit at 1000rpm log signals, then sit at 2000rpm, log again, and the signal you want for rpm will the the ones thats double the value in the second log!)

5) you should therefore be able to reverse engineer the CanDB, noting what the message ID's, message byte lengths and loactions / scalings are for each of the parameters you need to see


6) get one of the many electronics companies who do CAN gateway modules (racelogic, PI, DTA etc etc) to knock up a module that accepts your analogue sensor information (engine temp, rpm etc) and outputs a suitably addressed CAN message to your new dash

see, easy !!!

(most of the aftermarket engine control ECU's are now starting to have CAN capability, this may prove the easiest solution to use)

[EddyP]

You make it sound so very simple :lol:

Any ideas what it might cost for something like one of those modules from Pi/racelogic or whoever.

I know the Emerald ECU can output a CAN signal for a dash, however I don't know if its possible to mod the output signals to make it run something like a vw dash.

Life was so much easier when it was just a bunch of 20 wires or so :lol:

[Icarus_]

Emerald does have CAN but appears to only have support for AIM dash and that's it.

Pi/Pectel would want a fair few quid - £5K+ to do a job like that as a one off, packaged up, boxed product.

Your best bet is one the many random chinese companies that bang out a lot of the aftermarket ECU's.

[annodomini2]

For about a grand those companies i listed sell display units, you can use the digital and analogue inputs on the back of the display and produce the display in a format you're happy with.

Plus side if you get bored you can change it.

But of course you would need to develop it yourself.

[EddyP]

Ah, right well if its going to cost that much I may just buy an SPA dash instead :lol:

Thanks for the info though guys, very interesting