06-21-2015, 09:56 AM
Two things that might help in your tests:
1. Photodiodes and phototransistors are "turned on" by exposure to light, so the ohmmeter readings you get are affected by ambient light, so shielding, or shadowing the devices can change the reading that you see.
2. If you want to "see" infrared, take your old video camera, remove the lens and lift out the IR filter in front of the sensor. Replace the lens, look at your IR led's while your device is powered, and you should see a glow if they are live. I haven't tried looking at things with a phone camera, but that might work as well.
1. Photodiodes and phototransistors are "turned on" by exposure to light, so the ohmmeter readings you get are affected by ambient light, so shielding, or shadowing the devices can change the reading that you see.
2. If you want to "see" infrared, take your old video camera, remove the lens and lift out the IR filter in front of the sensor. Replace the lens, look at your IR led's while your device is powered, and you should see a glow if they are live. I haven't tried looking at things with a phone camera, but that might work as well.