Timeline for Light sensors sensitive enough to detect for PWM from CF and LEDs?
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
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| Mar 19, 2019 at 4:56 | comment | added | user57037 | If you are primarily interested in figuring out flicker frequency and PWM duty cycle, the sensor part of the problem is not too difficult. Photodiodes can easily handle a few kHz. | |
| Mar 19, 2019 at 0:02 | answer | added | Edgar Brown | timeline score: 3 | |
| Mar 18, 2019 at 21:11 | comment | added | jonk | This is going to be your problem: "There's no guarantee that one phone's sensor will product the same results as another." To avoid such a problem, you'll need to apply something called calibration. What you have to calibrate and how you calibrate it is another process. Since this is optical, you'll need tight control on the acceptance angle and may need to cope with polarization vagaries and specular vs matte emissions (why they show a diffuser on your page) and variations in the angle of the emitters vs your sensor system, etc. Tell us more about what you are trying to achieve/usage. | |
| Mar 18, 2019 at 20:34 | history | edited | crj11 | CC BY-SA 4.0 |
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| Mar 18, 2019 at 20:24 | answer | added | crj11 | timeline score: 2 | |
| Mar 18, 2019 at 18:19 | comment | added | dandavis | tap a photo dioide or photo transistor with an oscilloscope, you'll see the "readings" in real-time. You could also amplify the signal and output audio, allowing you to hear the blinking in frequencies of 500Hz-10kHz... | |
| Mar 18, 2019 at 17:57 | comment | added | Jack Creasey | You could try something like the BPW34: vishay.com/docs/81521/bpw34.pdf More than fast enough for the application. A simple Arduino solution would seem possible. | |
| Mar 18, 2019 at 17:49 | comment | added | Neil_UK | I also have 'fast eyes'. I think an ordinary phototransistor, biassed and amplified to give more or less linear output with light, with a DC and an AC detector, would give AC/DC = fractional amount of flicker. A selection of switchable low pass filters in the AC path would allow some crude discrimination of frequency of flicker. | |
| Mar 18, 2019 at 17:44 | comment | added | TimWescott | How sophisticated a readout do you want? Getting an electrical signal that shows how much flicker is pretty easy -- that just takes a photodiode and amplifier. Actually interpreting that is hard; either you need an oscilloscope-type output, which makes it hard for you, or some sort of a one-number "this is how bad the flicker is" number, which would take man-years of research to make it not be bogus. | |
| Mar 18, 2019 at 17:37 | history | asked | Zhro | CC BY-SA 4.0 |