Very strange accidental proximity sensor - Explanation wanted

[Ngineer]

Hello everybody,

I was working on an electronics project, and one of the LEDs (actually I'm using only one) started acting really strange!

It will light up when I come close to it, ONLY if I have been out of the room for some time!

And that's not all, the period for which it will light up is proportional to how much I have been away (i.e. the longer I stay far from it the longer it will light when I return)


I was thinking of 2 possible explanations how this can happen,

Explanation 1. When I get out of the room I somehow get electrically charged, and this creates an E-field around the led when I return, making it conductive.
(But it will do this even if I go the other way (i.e. what matters is that I stay out of range, not where I go))

Explanation 2. The accidental sensor (be it capacitive or otherwise) is dependent on a capacitor that needs time to charge between "activations." But in this case it has a really wide range because I have to move 3~4 meters to get it to light again for a second or two!

Any input on this is appreciated, thanks!

 

[skeptic2]

I think there's a third explanation. Could it be that the LED is in love with you and the longer you are away the more it misses you?

 

[Averagesupernova]

No possible way to give you any advice on this unless we see a schematic.

 

[Mike_In_Plano]

This gives me a grin. This is a classic when using CMOS components. When I was but a wee lad, my boss showed me a machine that he could actuate / de-actuate by waving his hand. It had an open gate and was picking up charge from his proximity (assumable he was charged).

 

[sherrellbc]

I had a similar event recently - something I could not explain but seems simpler than your situation.

I was working with a microcontroller and had an isolated LED/resistor tied to ground. If I came close to the anode of the LED, it would very slightly eluminated. I made sure that I was not touching any charged electronics.

More interestingly, if I firmly placed my feet on the ground then the LED would become dimmer. It seems that I was somehow conducting charge whilst sitting there.