Dear all,
For a project i am trying to measure transmission of light through a sample. For this I use an arduino uno with a Led and a photodiode. The circuit can be found here http://postimg.org/image/cywhaewsh/ . The photodiode is currently not properly working. Can someone of you see if there is a problem in my circuit?
Have you started measuring the voltage levels at the photodiode and the resistors that accompany it? What level of voltages and ADC values do you get/expect as a baseline (no sample under test). According to the response in this page you got the photodiode backwards: http://electronics.stackexchange.com/qu … -correctly
Also you are powering the 2 leds from a single pin (pin 13 that also powers the led on the Uno board) so it probably does not provide as much current to light them up sufficiently for your purposes. Does the photodiode give a better response when you provide light from a different brighter light source? Flashlight/Laser/lens-focus as a suggestion.