Sure, listening to VHF FM has great advantages over MW/LW AM from the old days ” now we have bright stereo free from interference, fading and noise! However, your FM radio will no longer predict the arrival of a thunderstorm as did the AM radio many years ago-reliably and hours before the trouble was upon you! The crux is that AM detection will
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faithfully reproduce the effects of lightning and other massive static discharges approaching in a very simple way: they`re audible as slight crackling noises in the loudspeaker, almost irrespective of the tuning of the radio! Assuming no AM radio is available anymore, a dedicated VLF receiver tuned to about 300 kHz can faithfully detect the crackle of approaching lightning. The simple receiver shown here consists of a loosely tuned amplifier driving a kind of flasher circuit that blinks an LED in synchronicity with the lightning bolts. The frequency and intensity of the LED activity indicates the intensity and distance of the storm respectively. Looking at the circuit diagram, the LED driver is not biased to flash until a burst of RF energy, amplified by T1, arrives at the base of T2. The receiver works off 3 volts and has a negligible standby current of about 350 microamperes which will hardly dent the shelf life of a couple of 1. 5-V D-size cells. T2 and T3 form a monostable generator triggered by sudden drops in T1`s collector voltage. Preset P1 is adjusted until the LED remains off when you`re sure there`s no thunderstorm around for a few hundred miles. The value of the LED series resistor is subject to experimentation and LED current. L2, C1 and the antenna are coarsely tuned for resonance at about 300 kHz. Frequency-wise, lightning is a fairly broadband phenomenon so any tuning to between 200 and 400 kHz will be fine...
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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