Automatic switching of LED garlands. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Beginner radio amateur

 Comments on the article

For the lighting design of the Christmas tree, garlands of incandescent lamps or LEDs are usually used, which are controlled by an automatic machine that turns on the garlands in a certain sequence.

The most popular modes in this case are those that create the effects of "running lights" or "running shadow". Their implementation requires two microcircuits - one is used in the generator node (for example, K561LA7, K561LN2), the other (K561IE8, K561IE9) - in the counter node with a decoder. But you can get by with only one K176IE12 chip by assembling the machine according to the scheme shown in fig. 2.

As you know, this microcircuit is intended mainly for electronic watches. It consists of an oscillator with an external quartz resonator and counters, in one of which pulses appear at the control outputs of the bits of the digital indicator, shifted in phase between themselves by a quarter of a period. For clarity, in Fig. 3 shows signal diagrams on some of the outputs of the microcircuit during the operation of the generator. For the sake of simplicity, the time scales of the diagrams are different.

At pin 14, as well as at pin 13, when the generator is running (instead of a quartz resonator, a frequency-setting circuit R1R2C1 is installed in it), there are pulses with a tuning frequency of the generator fr. At the output F, pulses appear with a frequency 32 times less than the frequency fr. Pulses at the outputs T1-T4 follow with an even lower frequency, moreover, each of them is 1/4 of the period and they appear sequentially. It is these signals that are needed to obtain these effects. The "longest" pulses appear at the output of S2 - 16384 times smaller than fr.

Transistor keys VT1 -VT4 are connected to the outputs T3 -T6 through limiting resistors R1-R4, each of which controls a garland of five LEDs connected in series. When the device is operating, that garland is lit, the control transistor of which is open at a high level at the corresponding output of the DD1 microcircuit. And since high-level signals will appear sequentially at the specified outputs of the microcircuit, the garlands will also be sequentially lit, creating the effect of "running lights" with the appropriate relative position of the LEDs. Since only one garland is lit at any time, only one limiting resistor, R7, is installed.

Using this microcircuit in the same way, but by installing transistors of the p-n-p structure (Fig. 4), you can get the "running shadow" effect. Now the transistors will open, which means that the corresponding garlands will turn on, with low-level signals at the above four outputs of the microcircuit. Therefore, the garlands will go out one by one, creating a "running shadow" effect. In this version, current-limiting resistors (R7-R10) had to be put in the circuit of each garland.

Of course, each of the described automata is capable of performing only one function. By supplementing the original design with another microcircuit (Fig. 5), you can get several options for switching garlands. The DD1 chip is included in the same way as in previous designs. But now the signals from its outputs T1 -T4 are fed to one of the inputs of the EXCLUSIVE OR elements of the DD2 microcircuit. This chip controls the operating modes of the machine. The second inputs of the elements are connected together and connected to the movable contact of the switch SA1 "Mode". Transistor keys are connected to the outputs of the microcircuit elements through limiting resistors, which control the switching on of LED garlands.

The mode of operation of the machine is changed by the switch SA1. In position "1", +2 V is applied to the input terminals of the elements of the DD12 microcircuit connected together. The logic elements work as inverters, the machine is in the "traveling shadow" mode.

In position "2" of the switch, the inputs of the logic elements are connected to a common wire, the elements work as repeaters, as a result of which the "running lights" mode is implemented.

In position "3" the second inputs of the elements of the DD2 chip are connected to the output S2 (pin 6) of the DD1 chip. The shape of the pulses at this output is "meander", the repetition rate is equal to fr / 16384, therefore, each such pulse will correspond to 64 pulses on any of the outputs T1 -T4. Half of the pulse period at the output S2, when there is a high level at it, the machine operates in the "running shadow" mode, and the second half, when the output S2 is low, in the "running lights" mode.

When the movable contact of the switch is moved to position "4", the inputs of the elements of the DD2 chip connected together are connected to the output F of the DD1 chip. The pulse frequency at this output is 8 times higher than at the outputs T1-T4. In this mode, the elements of the DD2 chip will change their functions 8 times more often than the garlands are switched, so the effect of pseudo-chaotic switching on of the LEDs will be created.

Positions "5" and "6" of the switch can be omitted, but it makes sense to talk about them. So, in any of these positions, all the garlands will start flashing at the frequency of the generator. Since it is relatively high, this will affect the brightness of the LEDs of the garlands - it will decrease. And although the effects of "running shadow" and "running lights" are still created, the LEDs do not go out completely. Nevertheless, the created effects are noticeable even in a lit room.

In addition to the K561LP2 microcircuit, KR1561LP2 is suitable, transistors - any of the KT315, KT3102 series, LEDs - any domestic or imported different colors of glow, a switch - any type for the specified number of positions and one direction.

Most of the details of this design are mounted on a printed circuit board (Fig. 6) made of one-sided foil fiberglass.

A variable resistor and a switch can be mounted on the front panel of the case, in which the board and power supply will be located - any low-power unit with a stabilized output voltage of 12 V and a load current of up to 100 mA.

Author: I.Potachin, Fokino, Bryansk region

See other articles Section Beginner radio amateur.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

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 ... >>

Primium Seneca keyboard 05.05.2024

Keyboards are an integral part of our daily computer work. However, one of the main problems that users face is noise, especially in the case of premium models. But with the new Seneca keyboard from Norbauer & Co, that may change. Seneca is not just a keyboard, it is the result of five years of development work to create the ideal device. Every aspect of this keyboard, from acoustic properties to mechanical characteristics, has been carefully considered and balanced. One of the key features of Seneca is its silent stabilizers, which solve the noise problem common to many keyboards. In addition, the keyboard supports various key widths, making it convenient for any user. Although Seneca is not yet available for purchase, it is scheduled for release in late summer. Norbauer & Co's Seneca represents new standards in keyboard design. Her ... >>

The world's tallest astronomical observatory opened 04.05.2024

Exploring space and its mysteries is a task that attracts the attention of astronomers from all over the world. In the fresh air of the high mountains, far from city light pollution, the stars and planets reveal their secrets with greater clarity. A new page is opening in the history of astronomy with the opening of the world's highest astronomical observatory - the Atacama Observatory of the University of Tokyo. The Atacama Observatory, located at an altitude of 5640 meters above sea level, opens up new opportunities for astronomers in the study of space. This site has become the highest location for a ground-based telescope, providing researchers with a unique tool for studying infrared waves in the Universe. Although the high altitude location provides clearer skies and less interference from the atmosphere, building an observatory on a high mountain poses enormous difficulties and challenges. However, despite the difficulties, the new observatory opens up broad research prospects for astronomers. ... >>

Random news from the Archive Found a reliable way to transfer energy without wires 27.04.2022 A team of scientists from the US Naval Research Laboratory has tested a new technology for wireless power transmission. Using microwave radiation, physicists managed to transmit electricity with a power of 1,6 kilowatts over a distance of 1 kilometer at the US Army research site in Blossom Point (Maryland). The Laboratory emphasizes that this is the most successful and reliable demonstration of wireless power transmission in the last 50 years. Energy beams are transmitted between two points within the Safe and Continuous Power bEaming - Microwave (SCOPE-M) system. Special equipment converts electricity into microwaves, which are then focused by a narrow beam on a receiver with the so-called rectennas (rectifying antenna - rectifying antenna) - this is a special type of receiving antenna with high-frequency diodes. When microwaves hit the rectenna, they are converted into direct current. For 12 months, American scientists have tried using SCOPE-M to transmit electricity in the form of a microwave beam with a frequency of 10 GHz in two places - at the Blossom Point test site, as well as at the Haystack ultra-wideband satellite imaging radar transmitter at the Massachusetts Institute of Technology (MIT). The result in Maryland was 60% higher peak power, but Massachusetts was above average, resulting in more power in the end. Scientists do not want to use a higher microwave frequency, because this will lead to energy loss when passing through the atmosphere. The 10 GHz frequency allows the use of cheap and reliable components, while the power loss is less than 5% even in heavy rain.

Other interesting news:

▪ Sound waves are the carrier of mass

▪ Happiness hormone can cause depression

▪ migraine on blood test

▪ Efficient triboelectric generator

▪ Logitech Wireless Solar Keyboard K750 for Mac

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Audio and video surveillance. Selection of articles

▪ article Happy feet. Popular expression

▪ article Why is the word untalented used incorrectly in today's everyday life? Detailed answer

▪ article Ferula gum. Legends, cultivation, methods of application

▪ article Homemade miniature LED base lamp. Encyclopedia of radio electronics and electrical engineering

▪ article About the modernization of the desktop air ionizer. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024