The handheld mini light beam receiver. On the left is a small solar cell, you can make out the various components on the circuit board through the transparent lid of the box. On the right, top and bottom, are the headphone and crystal earpiece sockets while the battery is just visible in its holder at the back (far right). I simply unplug the batt
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ery connector to turn the unit off. A very simple device to convert light into sound can be made by wiring a solar cell directly to headphones (or an earpiece). The solar cell converts light into electricity and the headphones convert electricity into sound. The limitation is that this set-up is very insensitive. What follows is a far more sensitive circuit as it contains a transistor amplifier which provides about x100 amplification. The circuit must rate as the simplest starting point to effectively listen to light! We have made what is effectively a simple preamplifier stage which for example can go before a pair of computer speakers. The circuit is capable of powering a crystal earpiece and (with some loss of volume) stereo walkman MP3 type headphones directly. As only the AC part of the signal goes through to the transistor it does not matter which way round you wire in the solar cell. So with just a handful of components and a battery you can start to re-explore the world with this little device - to hear what you have up to now only seen! 1) find a room with loud music playing (or orchestra playing) and when outside look out for sunlight reflected from one of the windows (or use torch / laser) and listen to the light - can you hear the orchestra on the light !. 3) listen to the dappled light from trees or from the ever changing surface of the sea / lake. Try listening to light shinning through a fan / extractor or...
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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