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By Rakshith_Parashurama
#198186
Hi all,

I am new in this forum. I am working on a project which is to read the OBD real time values out of a cars OBD pin. I am using the Sparkfun CAN bus Shield with the RedbearLab nRF51822 board. I am trying to create a plug and play module. The signals are to be read by a phone app which i am creating via bluetooth. Hence, i will not be using my laptop to power the module.

As far as the website, it states that "Power can supply to Arduino by sub-D via resettable fuse and reverse polarity protection". I dont know what this means.

How do i power my module with the help of the OBD pin?

Please help.
Thank you in advance.
#198191
Look at the schematic for the CAN shield
https://cdn.sparkfun.com/datasheets/Dev ... d_v13a.pdf
Pin 9 of the DE9 would connect to 12V in the car. Pin 2 (unless you played with the solder jumpers) is ground. Pin 9 connects to the Vin pin on the Arduino through a fuse (F1) and a reverse-voltage protection diode (D1). So that would power the Arduino. I'd add a bit more clamping on the 12V rail myself (cars are a notoriously noisy environment - look up "load dump"...) but you probably will be OK without it.

/mike