Sound keychain. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Beginner radio amateur
Comments on the article
This key fob beeps when lit. If you supply them, for example, with a bunch of keys, then the likelihood that they will be left somewhere will decrease. After all, the sound signal will constantly remind you that the keys must be put away in a dark place - in a pocket or in a case. In addition, it will make it easier to find the key fob with a flashlight if it was lost in the dark.
A key fob was assembled (Fig. 1) on one chip. A voltage comparator is made on the DD1.1 element, a rectangular pulse generator on the DD1.2 element, and buffer stages on the DD1.3, DD1.4. A piezoelectric emitter ZP-1 is used as an acoustic detector.
The device works like this. In the dark, the resistance of the phototransistor VT1 is high, so the inputs of the DD1.1 element will be a high logic level, and its output will be a low level. The generator is not working, the device is in standby mode, the current consumption does not exceed a few microamperes. This made it possible to do without a power switch.
If the phototransistor is illuminated, the voltage at the second input of the DD1.1 element will correspond to a low logic level, and a high logic level will appear at its output. The generator will start running. The key fob will emit a sound signal, the current consumption will increase to 1 mA.
All elements are placed on a printed circuit board (Fig. 2) made of one-sided foil fiberglass. Instead of that indicated in the diagram, you can use the K561TL1 chip, but the dimensions of the board will have to be increased. Instead of a phototransistor, a small-sized photoresistor with a dark resistance of more than 0,5 MΩ is suitable. Capacitors - K10-17, resistors - MLT, S2-33. As a power source, it is convenient to use "hourly" batteries or small-sized AAA cells connected in series.
Establishing the device is reduced to setting the desired tone of the audio signal by selecting the resistor R2 with temporarily closed outputs of the phototransistor. Then, by selecting the resistor R1, the sensitivity of the device to light is set.
The board together with the emitter and power supply (Fig. 3) must be placed in a case made of transparent insulating material.
Author: I. Nechaev, Kursk
See other articles Section Beginner radio amateur.
Read and write useful comments on this article.
<< Back
Latest news of science and technology, new electronics:
Traffic noise delays the growth of chicks
06.05.2024
The sounds that surround us in modern cities are becoming increasingly piercing. However, few people think about how this noise affects the animal world, especially such delicate creatures as chicks that have not yet hatched from their eggs. Recent research is shedding light on this issue, indicating serious consequences for their development and survival. Scientists have found that exposure of zebra diamondback chicks to traffic noise can cause serious disruption to their development. Experiments have shown that noise pollution can significantly delay their hatching, and those chicks that do emerge face a number of health-promoting problems. The researchers also found that the negative effects of noise pollution extend into the adult birds. Reduced chances of reproduction and decreased fertility indicate the long-term effects that traffic noise has on wildlife. The study results highlight the need ... >>
Wireless speaker Samsung Music Frame HW-LS60D
06.05.2024
In the world of modern audio technology, manufacturers strive not only for impeccable sound quality, but also for combining functionality with aesthetics. One of the latest innovative steps in this direction is the new Samsung Music Frame HW-LS60D wireless speaker system, presented at the 2024 World of Samsung event. The Samsung HW-LS60D is more than just a speaker system, it's the art of frame-style sound. The combination of a 6-speaker system with Dolby Atmos support and a stylish photo frame design makes this product the perfect addition to any interior. The new Samsung Music Frame features advanced technologies including Adaptive Audio that delivers clear dialogue at any volume level, and automatic room optimization for rich audio reproduction. With support for Spotify, Tidal Hi-Fi and Bluetooth 5.2 connections, as well as smart assistant integration, this speaker is ready to satisfy your ... >>
A New Way to Control and Manipulate Optical Signals
05.05.2024
The modern world of science and technology is developing rapidly, and every day new methods and technologies appear that open up new prospects for us in various fields. One such innovation is the development by German scientists of a new way to control optical signals, which could lead to significant progress in the field of photonics. Recent research has allowed German scientists to create a tunable waveplate inside a fused silica waveguide. This method, based on the use of a liquid crystal layer, allows one to effectively change the polarization of light passing through a waveguide. This technological breakthrough opens up new prospects for the development of compact and efficient photonic devices capable of processing large volumes of data. The electro-optical control of polarization provided by the new method could provide the basis for a new class of integrated photonic devices. This opens up great opportunities for ... >>
| Random news from the Archive Interaction of photons with pairs of atoms
25.08.2021
Scientists from the Federal Polytechnic School of Lausanne (EPFL) have for the first time forced photons to interact with pairs of atoms. This breakthrough is important for the field of resonator quantum electrodynamics (QED), an advanced field that underpins quantum technologies.
Humanity is moving towards the widespread use of technologies based on quantum physics. But to achieve this, you first need to master how to make light interact with matter - or, to be more precise, photons with atoms. To some extent, the advanced field of resonator quantum electrodynamics (QED) is responsible for such technologies. Now it is already used in quantum networks and quantum information processing. But there is still a long way to go. The current interactions of light and matter are limited to single atoms, which limits the ability of humans to study them in the form of complex systems involved in quantum technologies.
In the new work, the researchers used a Fermi gas (or Fermi-Dirac ideal gas). This is a gas consisting of particles that satisfy the Fermi-Dirac statistics, that is, they have a small mass and a high concentration. For example, electrons in a metal. “In the absence of photons, gas can be obtained in a state where atoms interact with each other, forming loosely bound pairs,” explains Jean-Philippe Brantou from the EPFL School of Basic Sciences. “When light enters a gas, some of these pairs turn into chemically bonded molecules, being absorbed photons".
The key concept of the new effect is that it happens "coherently". This means that a photon is absorbed to turn a couple of atoms into a molecule, then emitted back and so on several times. The para-photon system forms a new type of particle state, which is called pair polariton-polariton. This was made possible by a system where photons are trapped in one place, where they have to interact strongly with atoms.
Hybrid pair polaritons acquire some of the properties of photons. This means that they can be measured by optical methods. They also take on some of the properties of a Fermi gas.
In the future, the technology will come in handy in quantum chemistry: scientists have demonstrated for the first time how certain chemical reactions can be coherently produced using single photons.
|
Other interesting news:
▪ Abandoned mine and greenhouse effect
▪ Fish scales will speed up planes
▪ Eco-friendly steam generator for desalination and water treatment
▪ Bee beacon
▪ Human body for wireless communication
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ site section Lighting. Article selection
▪ article What the last book says to him, then it will fall on his soul from above. Popular expression
▪ article Why didn't anyone rush to save the wife of the Thai king Rama V when she was drowning? Detailed answer
▪ article Motorcycle fuel gauge. Personal transport
▪ article Automata lighting effects with chaotic inclusion of lamps. Encyclopedia of radio electronics and electrical engineering
▪ article Sticky coin. Focus Secret
Leave your comment on this article:
All languages of this page
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua
2000-2024
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese