7 years, 3 months ago.

Infrared light sensors.

Trying to figure out how to connect an infrared light sensor to the micro-controller FRDM KL25Z. Tried connecting the positive pin to a digital input of the controller. The negative pin was connected to the the ground in one case and to a reference pin in another case. Both did not yield the desired output. The objective was to detect whether an infrared LED was within range or not. Any suggestions?

Details on the sensor being used would probably help.

posted by Andy A 08 Oct 2014

2 Answers

7 years, 3 months ago.

Don't know anything about yor IR sensor. Maybe it needs some signal conditioning. Start with some datasheet.



7 years, 3 months ago.

an IR transistor will detect presence of IR radiation.

a usual IR sensor (like VS1838B) detects only signal when the modulation frequency is detected (around 38kHz). this means that the sensor will detect a signal only when you switch on-off your IR led with the above frequency. It does NOT detect the level of IR radiation.

So, if you want to detect IR radiation get an IR transistor. If you want to use an IR remote or a transmitter in general to communicate with your device, test it with an IR remote, not with an always lit IR led. Most Ir remotes use the 38kHz modulation frequency.

It may be useful to know that you can "see" an IR transmitter (to check if it is working or not etc) through a usual camera (your mobile phone's camera for instance) as Ir is visible for cameras.

Tell us your specific sensor, so we can help more if you still cannot make it work.