An article I read in Popular Electronics magazine from the 1980's inspired this experiment. The article was authored by Forrest Mims, renowned citizen scientist. In it he mentioned that he had discovered during the 1970's that LED's not only emitted light, but could detect light. This got my curious mind wondering if I could use the LED's I had aquired through Amazon from some far off foreign manufacturer extremely cheap. Like less than $5.00 for 100 each of 5 different colors could be used to detect light. It would appear they can.
Procedure: My lab (office) is on the second story of my home in S.W. Missouri, it has only one window facing due East.I waited until mid afternoon when the sun was in the western sky. Turned off the one artificial light in the room. Using the small bread board (about 2" square) that came with my Arduino Kit years ago, I inserted an LED and a couple of short pieces of wire to connect my DMM test leads too. I then instructed the DMM to collect 500 sample voltage readings and export the collected data to .csv files. I then suspended a small LED flashlight about an inch from the LED and ran another 500 samples. I repeated this process for all 5 colors of LED's, white, red, yellow, green and blue that came with this kit. The attached PDF files is a report of the raw findings.
Hope you enjoyed this, feel free to ask questions in the comments. I look forward to hopefully starting a discussion around this, maybe talk about how we can use this to discover life in far off galaxies (probably not), but maybe use it to have fun with our hobby is a more attainable goal.
Thanks
Charlie (Freebird)
