Joined Oct 15, 2009
put the batteries back in and press something metallic onto one of the 2 "squiggly" button contacts.. Then try the other.. Does the LED blink rate change or anything else..


Joined Apr 30, 2011
It's a cheap, single-sided board with no sensors and only a single switch input and LED output so it's either part of a toy, a safety blinker or a fake alarm blinker. When you "push" the button, it should turn on and off and may step through several blink patterns.

ian field

Joined Oct 27, 2012
I have no idea where any of the buttons (if there were buttons for this device) would have made contact. Could you please explain? I am a novice. Thanks a lot.
The interleaved fingers of conductive track either side of the LED are the switch contacts - they normally have silicon rubber button pads with conductive rubber blobs on the back that bridge those "fingers" when you press the button.

ian field

Joined Oct 27, 2012
So,.....could this be some sort of transmitter?
It could be an IR transmitter - if the LED didn't produce visible light.

It could well be part of a toy that a kid started to take apart before even getting home.

The board material looks like cheap SRBP, anything professional would have a glass fibre laminate PCB.


Joined Jan 18, 2008

Hi John, We have all made jokes about the unknown device, because no one can tell what it is from those pictures. As suggested, it may be a part of a larger device. Taking another tack, was there a large convention in town, particularly a medical or scientific one?

Many reagents used today in laboratory include small PCB's to do such things as calibration for each new lot or counting reagent use. That is, sort of like the counters included in printers to keep track of when the toner must be replaced. Those boards often have identification information printed on them. Your customer might have picked one up at a convention booth and accidentally dropped it in the cab.