Battery powered motion sensor current draw?

[K2]

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]

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 false
triggers, and the original batteries are still inside the units.
-Kim

 

[K2]

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 false
triggers, and the original batteries are still inside the units.

That's good to know.This will actually be in a sheltered area, blocked
by vehicles and aimed at one specific place where an intruder would
have to enter. I may also mask parts of the sensor to eliminate any
false alarms.

K2

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

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.

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]

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.

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.