April 2006 was the twentieth anniversary of the Chernobyl reactor accident. In the days following the incident winds deposited much of the reactor contents across central Europe, Scandinavia and the UK. A large area surrounding the reactor is still off limits but just how much of the fallout is still lying around on our gardens and farmlands At t
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he time of the release Iodine 131 was responsible for many cases of thyroid cancer but with a half life of 8. 1 days this does not pose much of a threat in the long term. Strontium 90 is more of a problem; it has a half life of 28 years and more than 50 % of the fallout still remains. Radio caesium affects the food chain and can contaminate milk, meat and to a lesser extent crops. Radioactivity is invisible so a detector is needed before we can start to make any measurements; the most common and simplest detector type is the Geiger counter. The design described here uses two NE555 type timer ICs, a small mains transformer and a few other standard components to make a low cost and simple to build Geiger counter. The only fly in the ointment is likely to be locating a Geiger-Mueller (GM) tube; this is not in any way a standard component. The on-line auction site eBay may provide a source of new or used counter tubes or alternatively Google will be useful in identify stockists. A brand new type ZP1300 tube can be purchased from ALRAD ( ) at a cost of £55. 00 plus VAT. The GM tubes are listed under nuclear products and nucleonics. The counter tube requires a high voltage in the region of 700 V. IC1 is a NE555 timer configured as an astable multivibrator switching the BC547C transistor which in turn drives the secondary winding of a 6 V mains transformer. An alternating voltage of around 250 V is produced at the primary side...
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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