How to test PWM frequency of flashlight without oscilloscope

cnyo

Newly Enlightened
Joined
Feb 7, 2013
Messages
11
1 Prepare an LED.This one is removed from a mouse.
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2 Find a multimeter which can measure the frequency .
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3 Turn on your flashlight, then you can measure the frequency of your flashliaght.
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The flashlight in picture is Olight i3
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AnAppleSnail

Flashlight Enthusiast
Joined
Aug 21, 2009
Messages
4,200
Location
South Hill, VA
Cool idea! Isn't that an optical sensor from the mouse though?

LEDs do generate a small bit of voltage when exposed to light - Most band gap things are reversible (Insert quantum physics to explain exactly why electron to photon is reversible). This would probably work best with a colored LED, and rather poorly with a white LED.

In short, an LED can work as a poor man's light sensor. The bullet-shaped ones are used in sun tracker projects to detect light and shadow.
 

GigaHz

Newly Enlightened
Joined
Jul 22, 2009
Messages
3
I wonder if an optical tachometer would work. We calibrate the tachometers with and LED and a synthesized generator.
 
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