Sensing Red LED

[ryukyu]

I am trying to use an LED (or CMOS RGB) sensor to determine if a red LED is illuminated. My idea is to use a red dichroic filter to block out as much ambient light and use an analog port on a microcontroller set at a threshold. I need this to work at ~6 inches away.

I have used a red camera lens (which I don't believe is the same as a dichroic) and detected the change between on and off with a blinking LED, but there really isn't enough filtering occurring to see a steadily lit LED.

Any optics people in the group think the dichroic will improve the results?

 

[Boncuk]

Hi ryukyu,

I'm not a specialist in optics but here is a suggestion you might try out.

There is red acrylic glass on the market used to "amplify" the red color of 7-segment displays.

May be that works for you.

Boncuk