Power solution for PIR camera trap


I have a field camera set up where a parallax PIR sensor triggers my SLR camera via an Arduino Uno. I am powering the Arduino with a typical 9V battery (not sure the amp hours on it but it's the typical over the counter one) and the 9V plug adapter you can get at Adafruit. My problem is that the Arduino runs out of power in less than one night. I didn't realize the PIR sensor would eat up so much power compared to the capacity of the battery. I have the sensor 15 ft. away from the arduino--I know the long connection increases the resistance for current reaching the sensor, but not sure if it affects power draw.

I would like the system to last at least a few days. I was hoping I could develop a fix with the batteries that I currently have available to me. I have 6V batteries ranging from 12-200ah and 12V batteries from 7.5ah to whatever a marine deep cycle battery is. Is there a way to power the arduino off these batteries without having to order more parts? If I do have to order something, would it be cheaper to get a higher power 9V, or a 6/12V and some sort of step down.

Thanks a lot for any advice. I have limited internet access and can't scour google for answers like I typically do, so any help from this forum would be greatly appreciated.

The Uno should be able to handle 12 V fine. I would try a 12 V battery with enough amps.

Summary Microcontroller ATmega328 Operating Voltage 5V Input Voltage (recommended) 7-12V Input Voltage (limits) 6-20V DC Current per I/O Pin 40 mA DC Current for 3.3V Pin 50 mA

Thanks a bunch for the quick reply. That's great news, I'll plug it to a 12V and stick the rig back in the field tonight... now I just need the critters to cooperate.

Extended use of battery power is all about having the best efficiency possible in the power section. Here is a handy little switching stepdown switching regulator. If will accept anything from 5 to 24 volts as input and will provide an adjustable regulated output voltage range of 2.5 to 12vdc. For your use you could utilize your 12vdc lead acid batteries as input, adjust the regulator for +5vdc output and wire the output directly to the arduino shields +5vdc and ground pin. That would raise efficiency as the on-board +5vdc regulator is of the non switching type and thus wastes power in regulating 12v down to 5v.


By the way those standard small 9vdc are the worst possible was to power an arduino board. They look cute with the handy little cable adapter, but is among the most costly battery on a MAH basis of any choice one could make.

Be sure to post some of the best picture you 'trap'