When the receiver is tuned to a M. W. radio station the resulting feedback howl, caused by the transmitter can be set to alter, or appear when the coil and radio are above or near a metal object Here is a pictured of the search head. It is made from a margarine tub. the small radio receiver is fitted inside the cover which is the wound coil on a disc
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. This is the schematic for the transmitter circuit which is housed in the box near the handle. The coil L1 is actually in the search head. the wires for this and the ear phones run down the handle hollow tube. I originally made this detector for the fun of doing the electronics and had no experience in the treasure seeking aspect of metal detectors. My son Bobby has this experience, so I decided to accompany him on a treasure hunt. We spent a whole Sunday afternoon searching a field which had been earmarked for house building and was lying redundant. My son was in charge of the spade work which pleased me, as this can be quite hard work on uncultivated ground. I operated the detector and found this, like fishing, completely addictive, with the well known, " just another five minutes" syndrome. The fading daylight finally finished the search for the day. The field lay alongside the railway lines and we started at the gate and walked along parallel with the lines, immediately the machine started to signal and did so every few minutes. after turning up many bolts nuts nails and scrap metal we came to the conclusion this was the area the railway workmen had used, and moved into the middle of the field. We now started to find more interesting items The first was a pocket knife in nice condition, I was intrigued by the stain at the tip of the blade It could have been blood or maybe tobacco. Later a brass button slightly bashed...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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