Battery powered motion sensor current draw?

Question

Do battery-powered motion sensors draw any significant current when no motion is present? This is a Heath-Zenith wireless system (about $40) that sends a signal to an indoor AC powered receiver when it detects motion. I'd like to know exactly how these things work. No current at idle?

How long might the sensor's 2 AA batteries last with an anticipated 3 or 4 triggers per day? Most would be false alarms from local cats. The packaging says 1 year, but doesn't specify at what trigger rate - or does that really matter? Thanks.

K2

Neil · Accepted Answer

Actually, you will find that the most false triggers are from wind, snow,rain, etc.. I have the same units, and 2 years later, with tons of falsetriggers, and the original batteries are still inside the units.-Kim

K2 · Answer

That's good to  will actually be in a sheltered area, blockedby vehicles and aimed at one specific place where an intruder wouldhave to enter. I may also mask parts of the sensor to eliminate anyfalse alarms.K2

Watson A.Name - "Watt Sun, th · Answer

The sensor may draw significant current, but the circuit is activated for a very brief time every second or so. So on the average, the current drain is very low. Also, 2 AA batteries can supply a decent amount of current; to see them in action check out a wireless optical mouse. The mouse is constantly glowing red, even when not moving, and the batteries last for a few months.

dh · Answer

The sensor itself probably draws very little current...though when an event is detected, there is probably a decent pulse for the wireless transmission.

A PIR sensor I'm working with now only draws about 5 uA by itself. Of course, you have to do some processing and amplification. I'm trying to get my microcontroller-based system below 200uA average.

Battery powered motion sensor current draw?

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