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I am trying to build a wireless motion detector that can work on a battery for a really long time. I am using this PIR sensor: http://www.digikey.ca/product-detail/en/555-28027/555-28027-ND/1774435

When there is no motion, the sensor is drawing about 100uA, as specified in the data sheet. However, when it detects motion the current consumption jumps to about 3mA, which is completely unacceptable for my low power design. I don't know much about PIR sensors, but I don't think this is supposed to be happening. My guess is that all the extra current is being drawn to illuminate two tiny red LEDs that are built into the circuit board under the lens.

Does this sound like the right assessment? The sensor itself should not be drawing any extra current when it detects motion, whereas LEDs can easily consume 3mA of current, right?

If this is correct, then it appears that I will either need to somehow disable the LEDs on the PIR (any suggestions how?), or I'll need to use a different PIR sensor in my design.

Can someone recommend another PIR I should look into that would be in the same price range?

Would something like this be a good choice? http://www.digikey.ca/product-detail/en/AMN34111/255-2649-ND/1137326

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Can you disconnect the LED? The spec is "130 µA idle, 23 mA active" from this page: parallax.com/Store/Sensors/ObjectDetection/tabid/176/CategoryID/… – markrages♦ Feb 20 at 22:10
You can just remove the LEDs with a soldering iron if you don't want them. – pjc50 Feb 20 at 23:09
@markrages: Oh yes - you are right it does say that. What does it mean for a PIR sensor to be "active"? I thought that it is always scanning for changes. Why does it need so much current when a change is detected? Would that be characteristic of all PIR sensors? – Val Blant Feb 21 at 19:19
I assume the extra current is the LEDs lighting up. "Normal" LED current is about 20 mA. – markrages♦ Feb 21 at 19:40

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