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220V
live Wire-in-Wall scanner: This
little circuit will help you to scan line of a 220V live wire in wall.
FET gate is connected to a capacitive metal sensor (which is usually a
simple metal plate). When you hold sensor close to wall, LED will
indicate current flow around where it detects wire. Works on 9VDC. (added
4/05)
Bandido II uMax: One of Tesoro's best designs. Schematic for
commercially-produced metal detectors (added 2/08)
Beat
Balance Metal Detector: (electronic design added 6/07)
BFO Metal
Detector: (electronic schematic / circuit added 4/02)
BFO Metal
Detector: (electronic circuit added 4/05)
Coil
Coupled Operation Metal Detector: (electronic design added 6/07)
Coil Coupled Operation Metal Detector: (electronic design added 6/07)
Compass 77b: Schematic for commercially-produced metal detectors (added
2/08)
Fisher 1212X: Schematic for commercially-produced metal detectors (added
2/08)
Gardiner 202A: Schematic for commercially-produced metal detectors
(added 2/08)
Heathkit Cointrack GD-1190: Schematic for commercially-produced metal
detectors (added 2/08)
Heathkit Groundtrack GD-1290: Schematic for commercially-produced metal
detectors (added 2/08)
Jetco Treasure Hawk: Department store BFO from the 70's. Schematic for
commercially-produced metal detectors (added 2/08)
Metal detector: A reasonably effective bfo (bifilar oscillator). Its
performance is not comparable to more advanced commercial products, of
course, but it still works. Anyway, during WWII metal detectors based on the
same principle were utilized my combat engineers of many armies to clear
mines.
The main idea is really quite simple: build two identical oscillators and
adjust them to the same frequency. One of the oscillators uses the search
coil while the second one incorporates a variable inductor. When both are
operating at the same frequency, the output is zero. If the search coil
moves near any metal, however, frequency of the first oscillator shifts and
an audible tone is heard in the headphones. (added 10/05)
Metal detector: (electronic design added 11/06)
Metal Detector Electronic Circuit: (electronic circuit added 4/05)
Metal detector Mk1: find hidden treasure at the beach… (circuit added
05/07)
Metal detector Mk2: More sophisticated 5 transistor metal detector
(BC547, BC557, BC338) (electronic schematic added 05/07)
Metal Detector uses Single IC: 12/12/97 EDN-Design Ideas / (added 3/03)
Metal Detector zen 22142: (electronic schematic / circuit added 4/02)
Simple BFO
metal detector: (electronic circuit added 4/05)
Simple metal detector Electronic circuit: (electronic circuit added
4/05)
Two-component metal detector: (electronic design added 11/06)
White's Goldmaster 66: A very early White's transistor design. Schematic
for commercially-produced metal detectors (added 2/08) |
