Pulse Induction Metal Detector Circuit Diagram

If the metal detector is over a metal object the pulse creates an opposite magnetic field in the object.

Pulse induction metal detector circuit diagram. With 2 ω circuit resistance and the minimum voltage of 9 volt the current over the coil will reach about 3 2 ampere in the 250µsec mentioned above which is more than adequate for a general purpose pulse induction metal detector with deep seeking capabilities. What i found were forums packed with very intelligent people working on homebrew detectors schematics circuits and designs with the electrical engineering knowledge to make very interesting and cost effective metal detectors. The operation of metal detectors is based upon the principles of electromagnetic induction. The coil transmits a pulse toward the ground generating an answering pulse from the target object.

For the general pulse induction pi detectors a magnetic field is created then deleted and the coil listens to slow eddy currents near the coil. The power supply four ic s the pulse generation circuit four 555 s and coil. Metal detectors contain one or more inductor coils that are used to interact with metallic elements on the ground. Schematic diagram of white s surfmaster pi metal detector a good quality simple pi pulse induction design with an affordable price.

A sampling circuit measures the pulse and sends it to an integrator which generates an audio tone. A pulse induction pi metal detector can be very easily implemented with a single greenpak configurable mixed signal ic cmic. Pulse induction metal detector with greenpak. Figure 2 block diagram of the pulse 1 metal detector the basic design of the metal detector consists of four parts as seen above.

Pulse induction pi metal detectors are sending repeated pulses of electrical current to the search coil producing a magnetic field. A block diagram of the circuit can be seen in figure 2. Pulse induction designs have the advantage of tolerance to ground effects and work even when submerged in water. Heathkit groundtrack gr 1290 vlf metal detector circuit diagram and detector coil construction notes.

A typical pi based metal detector sends about 100 pulses per second but the number can vary greatly based on the manufacturer and model ranging from a couple of dozen pulses per second to over a thousand. I was delighted to find several schematics for pulse induction vlf and cco detectors on the geotech forum. White s surfmaster pi pulse induction metal detector schematic diagram. In the lc trap version i assume that we are not really listening to slow eddy currents but rather changes in the inductivity and damping of the coil which might be due to creating eddy.

Pulse induction metal detector part 2 pdf metal.