Stabilising IR Receivers

william chan

Hi,

My SX is sleeping to save on the battery.
When an IR signal is received, it wakes up and then try to decode the IR signal.
To do this, the signal of the IR receiver is connected to one of the rb pins which will wake up the processor whenever pulled down.

Now, the problem is that the IR receiver is always receiving spurious signals which will toggle it's output every 10 - 30 seconds or so.
This causes the SX to wakeup for nothing, wasting the battery.

Any ideas on how to solve this problem?

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Beau Schwabe

william chan,

How much power is your IR detector consuming? I would think that any amount of power consumed during "wakeup"-->"read"-->"sleep" might be negligible depending on the type of IR detector you are using, especially since it would need to be "ON" all the time.

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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

william chan

Sharp has a part GP1UD that consumes only 200uA when idling.
I think it is the lowest power IR receiver money can buy.

www.sharpsma.com/Page.aspx/americas/en/238b8a1b-e348-417a-a2c2-426e09db5620

Is there a lower power part than this?

Any solutions for this problem?
Is it possible to implement a low power counter or integrator that wakes up the SX only after a few toggles in one burst?

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www.fd.com.my
www.mercedes.com.my

Post Edited (william chan) : 7/13/2008 8:25:18 AM GMT

Mike Green

You can always build an integrator out of a micropower comparator and some passive components. You can use an RC timer where the capacitor is constantly charged at one rate and discharged by the GP1UD at another rate. If the GP1UD is on a certain percent of the time, the comparator will trigger and wake up the SX.