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Hi,
I'm new to metal detector projects and decided to build a surfmaster PI for my first attempt. Goal was to be able to use parts from old circuit boards and electronic equipment that I had lying around and to minimise buying components. Didn't have the ICL7660, so built my own charge pump device using a 555. Had to add extra caps to the circuit to get rid of some parasitic noise.
The coil was made from speaker wire wound flat, inner diameter 12cm, outer diameter 24 cm, which got an inductance of around 220 microhenry. The coil housing was 3D printed as were the brackets. Only had to buy the CD4066 and MC14093 as well as the box, battery holder, and veroboard. Hardware store for the shaft and handle. Here are the pictures, showing circuit board, circuit board mounted in box, and completed detector. Total weight, 1.5 kg.
I learned heaps from this project (after many setbacks, scratching of my head, figuring out CRO signals, and lots of researching) and l was able to get it to detect ferrous metal at a depth of 25 cm, gold (0.5g) at about 10 cm. Quite happy with this first attempt and now understand a lot more about how PI detectors work (coming from a very low base).
Looking forward to learning heaps more reading all the information here and thinking about mods and the next project.
A newbie.
I'm new to metal detector projects and decided to build a surfmaster PI for my first attempt. Goal was to be able to use parts from old circuit boards and electronic equipment that I had lying around and to minimise buying components. Didn't have the ICL7660, so built my own charge pump device using a 555. Had to add extra caps to the circuit to get rid of some parasitic noise.
The coil was made from speaker wire wound flat, inner diameter 12cm, outer diameter 24 cm, which got an inductance of around 220 microhenry. The coil housing was 3D printed as were the brackets. Only had to buy the CD4066 and MC14093 as well as the box, battery holder, and veroboard. Hardware store for the shaft and handle. Here are the pictures, showing circuit board, circuit board mounted in box, and completed detector. Total weight, 1.5 kg.
I learned heaps from this project (after many setbacks, scratching of my head, figuring out CRO signals, and lots of researching) and l was able to get it to detect ferrous metal at a depth of 25 cm, gold (0.5g) at about 10 cm. Quite happy with this first attempt and now understand a lot more about how PI detectors work (coming from a very low base).
Looking forward to learning heaps more reading all the information here and thinking about mods and the next project.
A newbie.
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