Ok,
I have 2 sets of 6 infrared LEDs wired in series with a resistor. Using a 555 timer circuit, 1 set of these LEDs outputs a square pulse at 2.5 kHz while the other outputs the pulse at 4 kHz. Both have a 5% tolerance for the output. I need to find a circuit that will be able to read the frequency that is being output through these LEDs. I have tried a few different circuits using black phototransistors but haven't found the correct combination yet.
Any ideas?
UPDATE....I may need to be more specific. In general terms, the emitter is the infrared LEDs outputting the pulse at 2.5 or 4 kHz. I need to find a separate reciever circuit that reads the frequency of the emitter LEDs.
Thank you
I have 2 sets of 6 infrared LEDs wired in series with a resistor. Using a 555 timer circuit, 1 set of these LEDs outputs a square pulse at 2.5 kHz while the other outputs the pulse at 4 kHz. Both have a 5% tolerance for the output. I need to find a circuit that will be able to read the frequency that is being output through these LEDs. I have tried a few different circuits using black phototransistors but haven't found the correct combination yet.
Any ideas?
UPDATE....I may need to be more specific. In general terms, the emitter is the infrared LEDs outputting the pulse at 2.5 or 4 kHz. I need to find a separate reciever circuit that reads the frequency of the emitter LEDs.
Thank you
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