I think that using a 320M resistor is very stupid.
Your problems have nothing to do with step side and everything to do with picking up mains interference.
Well you could try a filter with a resistor and capacitor but it would be good to use a proper sensor and a realistic value of feed back resistor.
I just found this.5 minutes readinghttp://dkc1.digikey.com/us/en/tod/ADI/Top5Problems_NoAudio/Top5Problems_NoAudio.html
I know a decent sensor would be better, but a PAR sensor is in the price range of 180$
Mims reasoned that since LEDs take inelectricity and emit light (along that narrow emission band, remember), theyshould also take in light and give off electricity. A series of experiments provedhim right, and by 1973 he had formalized what is now known as the MimsEffect: LEDs will absorb light along a relatively narrow band of color, and emita small amount of electricity.
BillieBricks I corrected the schematic, but you are right: the gain is 10/0.1 = 100 , which is too much when using my photodiode, it should be about 15, so a 1.5 Mohm resistor should be suitable.
Mims reasoned that since LEDs take in ....
QuoteMims reasoned that since LEDs take in ....Is this the same person who suggested using a 320M resistor in the feedback of an op amp?I think his credibility is a bit blown by that.
So I looked at the book Atmospheric Monitoring with Arduino on Amazon and in the preview section I came across this diagram (attached).Any one who thinks that is the way to connect an LED to an arduino without damaging the arduino knows absolutely nothing about arduinos and electronics.
As this book according to Amazon has not been released how did you get a copy?
This is the bandwidth you are looking for:-http://www.licor.com/env/products/light/quantum_sensors/
Now do you actually think that can be replaced by an LED?
LEDs detect photons by creating electron hole pairs in the intrinsic region of a PN junction. These then get swept up by the potential barrier on each side of the intrinsic region and that represents a current.In order to create the electron hole pair the photon energy E which is hv (h = planks constant v = electromagnetic frequency) has to be greater than the gap between the valance band and the conduction band in the material of the junction. However, this is only the minimum energy, so while an LED will react to light at the same frequency that it emits and not to lower frequencies, it will also generate a photo current for photons of higher energy / frequency.I ask again how meaningful will measurements from an LED be?Well good luck.
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