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General tech discussions on all types of metal detectors: VLF, 2-box, BFO, off-resonance, PLL, etc. Questions, ideas, and anything else that moves you.
main difference is that mine counts the time it takes the coil falls below the reference voltage , his delays a predefined amount of time and then tests if the comparator is high or low
The main draw back of his design is that it is just using the cpu for counting time which from my experience is a mess
The attiny 15/25/45/85 series have dedicated timers that can be clocked from several hz to 85 mhz and are much more accurate
attiny 12 has a max cpu of 8 mhz and only 1 timer with a max frequency of 1.2mhz so I guess cpu was more accurate than that, but we've come a long ways!
His has a op amp which seems like a nice addition though!
Both projects share the same concept of using the analog comparator to see how long it takes
the signal to fall to near 0v (adjustable via multi turn trim pot)
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