hi, could anyone give me a detailed description of how this circuit works and where the bandpass filters are plz. circuits are in the link below:
**broken link removed**
this is the discription iv got now, but its sketchy on some parts and i dont know where the bandpass filters are(what parts they consist of)
im not even sure if its entirely correct. thnx a lot.
Description
The emitter uses a 555 timer to turn on and off the IR LED at a rate of 5khz. This sends out a 5khz square wave. By emitting a 5khz signal, the detector shouldn’t pick up any light sources other than the signal from the IR LED.
The detector receives the signal and sends it to an Op. Amp to amplify the incoming signal, after the first Op. Amp there is a bandpass filter which snubs out any signal received that isn’t at 5khz, which the emitter outputted. After the second bandpass filter, the signal is sent into a comparator.
If the - input to the comparator is greater, then the output will be -12 volts. If the + input is greater then the output of the comparator will be +12 volts.
The output of the detector will always put out either 0 volts, 12 volts or –12 volts, depending on which part of the signal is received so when an IR signal is detected, the output of the entire detector will be a 5khz signal with +12 volt and –12 volt peaks.
**broken link removed**
this is the discription iv got now, but its sketchy on some parts and i dont know where the bandpass filters are(what parts they consist of)
im not even sure if its entirely correct. thnx a lot.
Description
The emitter uses a 555 timer to turn on and off the IR LED at a rate of 5khz. This sends out a 5khz square wave. By emitting a 5khz signal, the detector shouldn’t pick up any light sources other than the signal from the IR LED.
The detector receives the signal and sends it to an Op. Amp to amplify the incoming signal, after the first Op. Amp there is a bandpass filter which snubs out any signal received that isn’t at 5khz, which the emitter outputted. After the second bandpass filter, the signal is sent into a comparator.
If the - input to the comparator is greater, then the output will be -12 volts. If the + input is greater then the output of the comparator will be +12 volts.
The output of the detector will always put out either 0 volts, 12 volts or –12 volts, depending on which part of the signal is received so when an IR signal is detected, the output of the entire detector will be a 5khz signal with +12 volt and –12 volt peaks.
