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I have an application where I have multiple IR transmitters/receivers set up to read data. These are removable and can be set up in a lab environment where I can control distance, light, etc. I've been searching for a circuit that will let me measure signal strength of an IR transmission, whether it be through a Microcontroller such as an Arduino or through a scope. However, all I see are people wanting to measure distance using IR.

My goal is to be able to take a brand new device(s) and get a signal strength baseline. Then I want to compare older devices to that baseline to see if signal strength degrades over time. Could anyone point me in a general direction?

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  • \$\begingroup\$ If you want to measure device aging, you probably need "real" measuring gear that is periodically calibrated against something you can have lasting faith in - otherwise you may be measuring the aging of your measuring rig. \$\endgroup\$
    – Chris Stratton
    Commented Jan 12, 2017 at 4:41
  • \$\begingroup\$ What are you trying to measure the degradation of? The Tx or RX device. In other words do you need a calibrated sender to measure RX sensitivity.....or a calibrated RX to measure sender IR output? \$\endgroup\$
    – Jack Creasey
    Commented Jan 12, 2017 at 5:05
  • \$\begingroup\$ I want to measure the Rx device. This device has both Tx and Rx, however, what I'm really interested in understanding is the Rx circuitry. \$\endgroup\$
    – Red Alert
    Commented Jan 12, 2017 at 12:26

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just connect a photodiode in parallel with a ferrite bead to the scope probe. it won't be particularly sensitive but it will give you something to compare against.

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  • \$\begingroup\$ Would I look for differences in the amplitude of the PWM waveform? That's where I was headed. The ferrite bead would be a nice addition and I hadn't thought of that yet. \$\endgroup\$
    – Red Alert
    Commented Jan 12, 2017 at 12:28
  • \$\begingroup\$ yeah, look at the amplitude, the ferrite bead should eat most of the hash produced by your room lights, which is otherwise likely to dominate the signal. \$\endgroup\$
    – Jasen Слава Україні
    Commented Jan 13, 2017 at 1:02
  • \$\begingroup\$ Thank you. I was intending on controlling my ambient light when I make my final fixture by enclosing it but I'm going to use the ferrite bead anyway. \$\endgroup\$
    – Red Alert
    Commented Jan 13, 2017 at 12:41

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