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What is a normal current draw for an arduino ATMega168 with nothing connected? Answered

I'm building a handheld geiger counter using an ATMega168 microcontroller with the arduino bootloader. I was planning on using a 9v battery with a 7805 to power the circuit since the geiger counter power supply only draws 3ma and I did not think an arduino would draw much current. however, after building it on protoboard I found that the total current draw on the battery was in the neighborhood of 170ma and drained a fresh 9v in a few minutes flat. The rest of the circuit continues to work without the arduino, and draws only 20ma when the micro has been removed. is it normal for an ATMega168 or 328 to draw 150ma when loaded with a minimal program and none of its I/O pins are sinking/sourcing any current? It is possible this chip has been mistreated somewhat, would it being slightly damaged cause it to use more power than usual? maybe using sleep mode aggressively in my code to save power would work? also, does anyone know of a 5v regulator chip like the 7805 that does not use so much current? the 7805 burns up about 10ma by itself which is not so great when the geiger counter itself uses only a few ma.


You're wasting a lot of energy in the regulator dropping 4 V in it

Worst case, for a raw chip should be ~12mA, so there is something wrong

A 168 will run at 1 meg on 1.8V supplies and consume only 240uA, so when you rebuild it, bear that in mind.

I was thinking about the same thing. The specs say that Arduino works at 7v to 14v. I was thinking about using the Li-Ion 3.7v batteries in series. Each one of them has more than 1 amp hour capacity. Would that be enough to Arduino entire night.

You can get voltage regulators that are buck converters that efficiently (~90+%) convert from your 9v down to 5v without burning off the excess as heat. I'd recommend worst case using 3 or 4 AA or AAA batteries instead of the 9v.

Steve has the best answer, the atmega chip should just SIP power unless you are running some crazy code -- perhaps internal pull-up resistors or something are to blame...

Yeah I was running it a few minutes ago and it was getting very warm, so that seems to be the problem. Got some 328's on the way so that should fix it. I need 5v for the geiger counter power supply, so running the chip at a lower voltage is not going to be possible. Sparkfun sells some single AA battery holders that have a small DC-DC converter built in to boost up to 5v, that would probably be a far better solution than a 9v and a 7805.