- Reaction score
- 4,325
q12x Good afternoon. I spent a couple of hours on my version 3, the one which uses pulsed ir light rather than continuous illumination in versions 1 and 2. The pulsing is about 100kHz. The received waveform produced by the ir sensor array is displayed in yellow in the video clip below. The amplitude of the received waveform, which is the combined output of the four photodiodes, varies with the proximity of the hand. I cannot remember if I showed you this variation before. What I did this afternoon is construct a peak detection circuit the output of which is displayed as the blue horizontal line on my scope sitting on top of the peak amplitude of the yellow waveform. Unless my finders are in front of the array it is detecting the side of my scope. You can see the voltage output by the peak detector in Blue following the amplitude of the received Yellow waveform. It is this Blue signal which I will input to my 8 comparators. I will look at the output of the comparators only when the ir illuminators send a pulse of light in order to distinguish between this illumination and background illumination.
How are you getting on? Regards
marconi
How are you getting on? Regards
marconi