Could anybody guide me testing of RED LED in production.


My intension is to test ON/OFF/Blinking condition of RED LED.

As per my thought - I need an optical sensor to sense the output of LED and then this signal goes to microcontroller and through UART we can get LED status in PC.


Could anybody recommend me optical part no or any alternate method to do this.

 

I think you need to give more details such as how far away from the LED will the detector be mounted and will it be used with some lens or mirror optics. Some pictures of the device that contains the LED and the positioning of the device in relation to the sensor would also be helpful. For example is the device on a moving conveyer belt and is the LED facing upwards ?

Les.

 

I think you need to give more details such as how far away from the LED will the detector be mounted and will it be used with some lens or mirror optics. Some pictures of the device that contains the LED and the positioning of the device in relation to the sensor would also be helpful. For example is the device on a moving conveyer belt and is the LED facing upwards ?

Les.

We are not going to use moving convener. We have BON setup under which we have to test the main board. There is no issue of detector mounting in BON. It can be done using child PCB.

So please suggest freely !!!

 

I think almost any phototransistor or phtodiode could be used. A phototransistor would probably drive an I/O port pin directly on a microcontroller with just a pull up resistor. (Or possibly just enabling the internal pull up on the pin.) A photodiode would probably need some amplification. This is a link to phototransistors stocked by Farnell
http://uk.farnell.com/webapp/wcs/st...tegoryId=700000006140&langId=44&storeId=10151
But is you search any component stockist for "phototransistor" you should find a suitable one.

Les.

 

I have used the Taos Semi TCS3200D-TR light sensor for testing LED's in my products.

It's got a range switch to cover a nice big dynamic range, the output is a pulse train, no analog monkey business.

 

Thank you so much

 

In case you happen to use Labview to control your test rig, you can put a cheap USB HD webcam above the board and use Vision Assistant to look for the light(s). Then it just becomes another automated step in the test. We use it for testing LCDs, 7 segment displays, indicator lights etc.

 

In case you happen to use Labview to control your test rig, you can put a cheap USB HD webcam above the board and use Vision Assistant to look for the light(s). Then it just becomes another automated step in the test. We use it for testing LCDs, 7 segment displays, indicator lights etc.

Thank you so much