Hi,
Now with my first detector project almost finished, I feel like it's time to move on to a next one
Not decided much on the way it will work, but I want to improve (compared to 1st one) the detection depth and investigate the possibility to discrimination. The soil around here does not seem to be too mineralized, so I don't know if ground balance will be of any benefit, but might want to incorporate that as well. Also need to study more the differential front end scheme, if it would prove any significant improvement. It looks like it should not be too hard with a bifiliar wound coil.
I've been reading these forums to some degree, but the information seems scattered through here and there, sometimes with confusing results too. So I'd appreciate if you could help with a few things.
1st of all, how does discrimination information present itself in the decay waveform? I like to work with digital stuff, so thinking in the lines of a fast AD-converter + enough computing power to crunch the numbers.. Then about the ground balance, how does the whole thing generally work? From what I've gathered, the ground "level" is sampled, and deduced from the target signal, to get targer responce ignoring ground. But at what stage of the decay curve is the ground sampling taken?
If you could help answer these, or point to a project where these have been implemented in practice and documented, that would be even better.
Anyways, for starters I want to start tinkering with the coil, and other bits associated. By the looks of things it seems the most effective way would be to go for a lower turn count, but high amperage coil.. To get the fastest possible coil quenching versus. induced magnetic flux. Of course, that creates the problem of finding a high amperage, high voltage coil switch. Maybe investigate the suitability of an IGBT switch?
Looks like lots of fun right from the beginning =)
Now with my first detector project almost finished, I feel like it's time to move on to a next one

Not decided much on the way it will work, but I want to improve (compared to 1st one) the detection depth and investigate the possibility to discrimination. The soil around here does not seem to be too mineralized, so I don't know if ground balance will be of any benefit, but might want to incorporate that as well. Also need to study more the differential front end scheme, if it would prove any significant improvement. It looks like it should not be too hard with a bifiliar wound coil.
I've been reading these forums to some degree, but the information seems scattered through here and there, sometimes with confusing results too. So I'd appreciate if you could help with a few things.
1st of all, how does discrimination information present itself in the decay waveform? I like to work with digital stuff, so thinking in the lines of a fast AD-converter + enough computing power to crunch the numbers.. Then about the ground balance, how does the whole thing generally work? From what I've gathered, the ground "level" is sampled, and deduced from the target signal, to get targer responce ignoring ground. But at what stage of the decay curve is the ground sampling taken?
If you could help answer these, or point to a project where these have been implemented in practice and documented, that would be even better.
Anyways, for starters I want to start tinkering with the coil, and other bits associated. By the looks of things it seems the most effective way would be to go for a lower turn count, but high amperage coil.. To get the fastest possible coil quenching versus. induced magnetic flux. Of course, that creates the problem of finding a high amperage, high voltage coil switch. Maybe investigate the suitability of an IGBT switch?
Looks like lots of fun right from the beginning =)
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