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Hi! I’m very new to this whole metal detector thing. My experience with metal detectors begins and ends with a toy that came with a magazine I got when I was about ten. From memory, it could barely detect a car from about an inch away.
I have an application that may benefit from a metal detector - I’m trying to detect a metallic particle within a cylindrical volume approximately 50 mm in diameter and 50 mm deep. The volume is filled with a mildly conductive saline solution (roughly 1 S/m). The coil must be static, placed at one end of the cylinder and cannot be moved during the measurement. I’m able to sample for several seconds if needed to help minimise noise. I could also perform a calibration on a known sample before measurement if required.
Probably the most challenging aspect is that the particles I need to detect can be as small as 0.2mm³. Most particles are ferrous, and I don’t need any information other than the presence or absence of metal.
The coil geometry is also limited - the diameter can’t be much wider than the detection cylinder. The coil geometry and conductive medium are pushing me towards a PI detector with a mono coil (hence posting in this section), but I’ve heard they aren’t as good as VLF for small targets.
I’m a lot better at the digital/software side than analog (every idiot can count to 1). As schematics with more than a handful of op-amps scare me, my instinct is to do as much digitally as possible. I plan to have a minimal analog frontend - just enough to get the signal into an ADC without introducing too much noise.
Does this sound like something that’s possible? I’d really appreciate any tips/pointers/information that may help. I’ve been binge-reading anything I can find for the last couple of weeks, but I’m sure there’s plenty of useful information I’ve missed.
Thanks in advance!
I have an application that may benefit from a metal detector - I’m trying to detect a metallic particle within a cylindrical volume approximately 50 mm in diameter and 50 mm deep. The volume is filled with a mildly conductive saline solution (roughly 1 S/m). The coil must be static, placed at one end of the cylinder and cannot be moved during the measurement. I’m able to sample for several seconds if needed to help minimise noise. I could also perform a calibration on a known sample before measurement if required.
Probably the most challenging aspect is that the particles I need to detect can be as small as 0.2mm³. Most particles are ferrous, and I don’t need any information other than the presence or absence of metal.
The coil geometry is also limited - the diameter can’t be much wider than the detection cylinder. The coil geometry and conductive medium are pushing me towards a PI detector with a mono coil (hence posting in this section), but I’ve heard they aren’t as good as VLF for small targets.
I’m a lot better at the digital/software side than analog (every idiot can count to 1). As schematics with more than a handful of op-amps scare me, my instinct is to do as much digitally as possible. I plan to have a minimal analog frontend - just enough to get the signal into an ADC without introducing too much noise.
Does this sound like something that’s possible? I’d really appreciate any tips/pointers/information that may help. I’ve been binge-reading anything I can find for the last couple of weeks, but I’m sure there’s plenty of useful information I’ve missed.
Thanks in advance!
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