Hello,

I'm trying to create an independent switch that closes and opens synchronously with a store bought product that contains a blinking LED.

My hope is to find the absolute smallest chip that I could tie right into LED hot (red LED, powered via 3V coin battery) with isolated contacts.

So I found this device locally and picked one up to play with, I remember the bin with the reel in it mentioned something about a micromini relay or something. I thought I'd just pick up a datasheet at home. But I can't find one!

The chip is labeled "NEC 2703 K613" and that's it. 4 pin surface mount IC. Closest thing I can find is an optocoupler that has an identical package. I figure many of these manufacturers are making the same parts anyways, and I'm just trying to get by with my project. All of the same device I can find seem to share pinouts too, implying if I were to "guess" here, I'd have a good chance of succeeding.

But it'd be nice to know I can make it switch sufficiently with 3V on the input. The contactors will switch a portion of the circuit on the same board, presumably 3V too. All very very low currents here.

I'd love for anyone's thoughts or input.

 

couldnt you just tie the pulsing line to the base of a transistor and feed a separate circuit?
just verify which line is pulsing the led, the negative or the positive. use a PNP or NPN accordingly.