Looking for help with Canbus buffer

[avz]

Hi
I want to install a reversing camera on my Toyota Yaris. as far as I know it's equipped with a canbus system, which, as far as I know- shouldn't be loaded with additional load. is it possible to connect to the reverse light bulb of the vehicle using a simple buffer circuit which will not load it and if so, could you offer a circuit diagram of such a buffer?

 

[Nigel Goodwin]

Have you actually tried just connecting the camera?, it should be a fairly small load and not enough to upset anything.

 

[avz]

No, I haven't tried. I'm afraid that it will cause some damage. I know that it's not allowed to connect a trailer without the dedicated unit. it makes sense since the load in case of a trailer is much bigger and load of the camera is quite low, but as the saying goes -better safe than sorry.

 

[Nigel Goodwin]

It won't cause any damage anyway, so give it a try. If you want to minimise the loading, you would need a separate power feed for the camera, and switch that from the reversing light.

 

[avz]

I'll give it a try/ it will have an additional load because instead of routing a cable for the camera from one end of the vehicle to the other end, I've purchased a transmitter that transmits the signal from the camera to a receiver next to the display.

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I hope it's not drawing too much current either.

 

[Diver300]

The vast majority of cars have CANbus systems, which was just about universal by 2000. CANbus communication systems are badly understood systems that are blamed for everything.

An example is the LED lights that are said to be "CANbus compatible" when they have a resistor in parallel so that they take some current at low voltage. Those resistors will be detected by some blown bulb detection systems, which otherwise say that the bulb is blown because the car is expecting an incandescent bulb. That has nothing to do with the CANbus, which may or may not connect electronic modules on a car, but won't connect directly to a bulb.

Any car that has a incandescent reversing lamps can have a reversing sensor put in parallel with the reversing lamp. The lamp will take about 2 A and the 100 mA or less that reversing sensors take won't make any difference. The worst case is that if the reversing light blows, some cars will shut of the light that isn't taking current, so that would make the reversing sensor stop if the bulb blows.

 

[avz]

Diver300 thanx for the comprehensive explanation. if I got it right, according to it, about 100mA can be drawn safely without causing any problems. if that's the case indeed, it's a great relief for me.