I am looking to detect the amount of light coming from a specific direction that lands in a specific area on a PCB. In my research, I have only found ambient light sensors and never any kind of directional light sensor. I want to confirm that there is no kind of existing IC package for sensing directional light.
My idea is therefore to take an ambient light sensor and shroud it to shrink the field of view. My sensor will be on a PCB. I am thinking about 3D printing a tube in matte black and attaching it to the PCB over the ambient light sensor IC. However, I'm not sure what the most durable way to attach the shroud around the sensor would be — I'd like something better than glue. I was wondering if there is some kind of PCB component I could include in my design so that the shroud could be soldered or screwed on.
- Is there such a component as a directional light sensor?
- What are good methods for fabricating a shroud for an ambient light sensor?
- What are good methods for attaching the shroud around an ambient light sensor on a PCB?
Best Answer
The custom shroud may be the easiest solution. There are a few variables that may change things depending on your application requirements such as, the light intensity, required sensor sensitivity, and resolution.
When directing light with LEDs, you can use a 'collimator' or a 'light pipe' both are available through digikey and other electronics suppliers.
collimator: http://www.digikey.com/product-search/en/optoelectronics/optics-leds-lamps-lenses/525154?k=collimator
light pipe: http://www.digikey.com/product-search/en/optoelectronics/optics-leds-light-pipes/524541
If you were doing a simple binary yes/no light is hitting here (maybe with a laser or focused high intensity light). I would use an LED and light pipe and used the LED as the photosensor. If you have incredibly low lighting, I would go with photoresistor and shroud.
If you can find a clear light pipe that matches the footprint of your sensor, you'd have the perfect solution.