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Old 02-26-2019, 02:58 PM   #70
T0rt0r0
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Quote:
Originally Posted by aznchris View Post
Sorry I'm new to using these little project boards and arduinos and stuff, but I'm assuming the RS232->OBD2 cable will power the arduino automatically through the CAN shield? Where do I stick the capacitors so I don't have to worry about power draw when the car is off?
The CAN shield can power the arduino BUT if you do that it will always be powered even with the car off and locked (like for an oft etc).

To avoid this issue, you could:
- use an obd cable with an on/off button and use it accordingly,
- power the arduino using for example the glove box power adapter +12v and put capacitors on the vin/gnd pins (see https://components101.com/sites/defa...in-Diagram.png).

There is a third option that is to develop some code to make the arduino to go to sleep mode when the car is off to avoid draining to much current but as the second option suited me well and as there is not really a lot of folks to use this ...

I'm still surprised that the obd connector don't provide both permanent and after ignition +12v wires

Hope this helps !
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