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Topic: CAN Bus 12V too much for Arduino Uno?? (Read 2435 times) previous topic - next topic

djenriquez

Mar 05, 2012, 02:21 am Last Edit: Mar 05, 2012, 02:58 am by djenriquez Reason: 1
Hey guys,

I'm having issues with my Arduino Uno SMD R2 overheating with my current application for it.

I currently have a Seeeduino GPRS v1.2 shield and CAN BUS shield attached to the microcontroller. The device is powered on from the vehicle by means of OBD-II to DB9 connector. I have the CANbus shield on top, GPRS shield on the middle, and Arduino on the bottom.

The devices works perfectly well collecting the data that I'm needing it to, however after a certain amount of time, I've noticed the GPRS shield powers itself off. When this happens, the arduino board is incredibly hot right underneath the 5V input/RUS 117-5 chip.

At first I thought it was issues with the code, so I rewrote it so that if it notices the GPRS is turned off, it will power it back on again. This works the first couple of times it turns off, but eventually the GPRS will no longer turn back on again.

The CANbus shield's power indicator and the Arduino Uno's power indicator are both lit, but I believe, based on what I've read from other threads, that it is no longer processing anything from my code because of the heat.

Sometimes, if I press the reset button the CANbus shield for 5+ seconds, then release, the GPRS turns back on again, but shortly afterwards, powers off once again.

Is overheating really my issue here? If so, what can I do to overcome this problem?

zoomkat

What is the measured voltage between the arduino +5v pin and arduino ground when your components are being powered from the vehicle?
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djenriquez

Thanks for the reply zoomkat,

I measured the 5V pin to ground at 4.9-5.0V, 3.3V pin at 2.9V when the vehicle is off or on.

However, the VIN, when the vehicle is off is at 12V, but with the vehicle on, jumps to 13.8V. Would this be the problem? I thought i read somewhere the VIN can go from 6-20V.

Knowing that the devices are connected in parallel, adding another resistor in parallel will not drive the current down, so would i need a transistor of some sort? I'm pretty new with circuit manipulation, any help would be appreciated.

djenriquez

any ideas anyone? or any advice to figuring this out wud b much appreciated as well.

winner10920

Id guess the linear regulator is your problem, its wasting so much energy(13.8-5v=8.8v) as heat that it probably shuts down
you may need a switching regulator and directly feed the 5v bus, as the gps probably draws alot

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