Starter for halogen lamps on the Z8 microcontroller

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

Starter for halogen lamps on the Z8 microcontroller. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Microcontrollers

Comments on the article

Recently, halogen spotlights and lamps are increasingly used to illuminate summer cottages and individual country houses. However, in our climate, the life of the lamps in these devices is short. This is due, first of all, to the inrush current, which destroys the cold filament of the lamp when it is turned on.

To eliminate this surge, a so-called start-up device (PU) has been developed, which ensures smooth switching on of any incandescent lamps, including halogen ones. In addition, the device is able to smoothly turn off the load and reduce the voltage on it by about 10% of the nominal mains voltage, which increases the life of the lamps when connected to a mains voltage of more than 220 V.

The main characteristics of the PU are as follows: supply voltage - 220 V ± 20%; turn-on (turn-off) time 10s; consumed current - no more than 40 mA. The maximum value of the load current and the limit value of the switched power are determined by the triac used and its heat sink.

Schematic diagram of PU is shown in fig. 2.

(click to enlarge)

Its basis is the same microcontroller Z86E0208PSC (DD1), "flashed" with the codes from Table. 3, which provide the required algorithm for turning on and off the load. The clock frequency DD1 is set by a circuit consisting of a quartz resonator Q1 and capacitors C4, C5 with a capacity of 22 ... 33 pF.

(click to enlarge)

The device is powered by a transformerless source, which differs from the similar unit of the "Cross" device by using a full-wave rectifier VD1, which made it possible to reduce the capacitance of the "quenching" capacitor C3.

The load circuit is controlled by a pair of components, consisting of a power triac VS1 and an optocoupler U1. The HL1 LED lights up and goes out synchronously with the load, indicating the correctness of the algorithm (if the indication is not needed, it is replaced with a jumper, and instead of R5 with a resistance of 240 Ohms, a resistor with a resistance of 360 Ohms is installed).

As U1, a triac optocoupler with an arbitrary switching moment is used, which makes it possible to smoothly change the brightness of the load glow. It is permissible to use any analogs of Motorola's MOC3023 optocouplers (MOC3022, MOC3052. MOC3053, etc.), devices without signal passage control through zero of higher classes. For the same purpose, a special hardware-software mechanism for synchronizing the operation of the device program with the time-frequency characteristics of the network is implemented in the PU. The synchronization unit is assembled on a transistor VT1. The number of elements of this circuit can be reduced if it is performed similarly to a similar controller node "cross chameleon"' (i.e., leave the resistor R3 with a nominal value of 2 MΩ. Protective diode VD3, turn on the jumper connecting the contact pads for the terminals of the base and collector VT1, and add a diode that performs functions similar to the VD4 diode in Fig. 1).

The output stage of the PU does not pass the first half-wave of alternating voltage to the load when the device is connected to the network. For this purpose, the R1C12R9 circuit is included in the control circuit of the triac VS13.

Local smooth switching on / off of the load and control of output power reduction is carried out through pins 5 ("On / Off)" and 7 ("Limitation 10%") of connector X1 (they transmit commands to work out or prohibit the processing of corresponding algorithms by the DD1 microcontroller) . To set a shutdown command, contact 6 is connected to the common wire of the device (pin 1) (with an external switch SA5), pin 7, and the output power limit command (by an external jumper) is pin 5. The presence of these connections is determined by the controller only at the moment the device is connected to the network. Both circuits are equipped with diode-capacitive protection (VD7C6 and VD8C3). excluding the passage of impulse noise to the microcontroller. However, the length of the wires connecting the control panel with the switch is limited and should not exceed 5 ... XNUMX m. If this requirement is not met, the microcontroller may fail due to interference induced on the wires.

As switch SA1. used for local control of the operation of the remote control, a conventional mains switch or a toggle switch with position fixing will do. If its contacts open, the PU gradually increases the power at the load for 10 s, and if it closes. - works out the algorithm of its smooth decrease during the same time. In the absence of a local control circuit, only smooth switching on of the load is ensured (when the device is turned off, the output voltage decreases abruptly).

To control the operation of the PU from a long distance, a node assembled on the U2 optocoupler is used (in this case, pins 2 and 9 of the DD1 microcontroller are connected with a jumper). When the input circuit is de-energized, the control panel operates in the normal mode (the operation of the device is allowed). Applying mains voltage to the input (pins 8 and 9 of connector X1) leads to the appearance of current through the capacitor C11 and the ignition of the optocoupler LED. Connected by a jumper pins 2 and 9 of the microcontroller DD1 are connected to its GND pin. As a result, the microcontroller stops processing switching algorithms (device operation is disabled), gradually reducing the voltage at the load. Although the instrument remains powered, the processor is blocked by the remote control signal in this case.

For remote control, a conventional mains switch is used. They can switch several PU. connected in parallel and located at a considerable distance from one another.

Reducing the effective value of the output voltage at the load by 10% in relation to the effective value of the mains voltage is achieved by changing the shape of the output signal (cutting the sinusoid). The device does not contain any special devices for monitoring the mains voltage or the voltage at the load, the microcontroller simply lowers the output voltage by 10% relative to the mains voltage. For this reason, it is not recommended to use this mode in networks with a greatly underestimated effective voltage value. It should be remembered that at voltages below 150 ... 180 V, the bulbs of most modern halogen lamps cannot warm up to the temperature required for the halogen effect to occur, so they quickly fail.

Since the output voltage in the limiting mode is not sinusoidal, devices that allow you to control arbitrary waveforms are used to accurately measure its effective value.

Capacitors K3-9 are recommended as C11, C73, C17, the rest of the parts are any small.

The value of the current switched by the triac VS1 depends on the heat sink. So, if a plate with dimensions of 40> 90 mm made of sheet aluminum alloy 3 mm thick is used for cooling, a load with a power of up to 500 W can be connected to the PU. With a plate of the same material, but 60x90 mm in size, the triac can operate on a load with a power of up to 1 kW. In this case, the PU, together with the triac heat sink, is freely placed in a case for five three-inch floppy disks (dimensions - 110x110x20 mm).

With the help of the described control panel, you can smoothly turn on a more powerful load if, instead of the one indicated on the diagram, you use a triac that can switch higher values of the load current (for example, TS 112-16. TS 122-25. TS 132-40 with heat sinks 0111, 0221, 0231 respectively). Since the control current of these devices is much larger, it is necessary, firstly, to change the parameters of the R12C9R13 circuit (reduce the resistance of the resistor R13 to 1,2 kOhm and increase the capacitance of the capacitor C9 to 0,22 μF). And secondly, solder jumper S1 from contacts 2-3 to 1-2 in order to use an external triac VS1 instead of the VS2 installed on the board. The latter is mounted on a heat sink and connected to the board with short wires. Of course, for such a design, a more spacious case is needed.

Authors: A. Olkhovsky, S. Shcheglov, A. Matevosov, K. Chernyavsky, Moscow

See other articles Section Microcontrollers.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

The threat of space debris to the Earth's magnetic field 01.05.2024

More and more often we hear about an increase in the amount of space debris surrounding our planet. However, it is not only active satellites and spacecraft that contribute to this problem, but also debris from old missions. The growing number of satellites launched by companies like SpaceX creates not only opportunities for the development of the Internet, but also serious threats to space security. Experts are now turning their attention to the potential implications for the Earth's magnetic field. Dr. Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics emphasizes that companies are rapidly deploying satellite constellations, and the number of satellites could grow to 100 in the next decade. The rapid development of these cosmic armadas of satellites can lead to contamination of the Earth's plasma environment with dangerous debris and a threat to the stability of the magnetosphere. Metal debris from used rockets can disrupt the ionosphere and magnetosphere. Both of these systems play a key role in protecting the atmosphere and maintaining ... >>

Solidification of bulk substances 30.04.2024

There are quite a few mysteries in the world of science, and one of them is the strange behavior of bulk materials. They may behave like a solid but suddenly turn into a flowing liquid. This phenomenon has attracted the attention of many researchers, and we may finally be getting closer to solving this mystery. Imagine sand in an hourglass. It usually flows freely, but in some cases its particles begin to get stuck, turning from a liquid to a solid. This transition has important implications for many areas, from drug production to construction. Researchers from the USA have attempted to describe this phenomenon and come closer to understanding it. In the study, the scientists conducted simulations in the laboratory using data from bags of polystyrene beads. They found that the vibrations within these sets had specific frequencies, meaning that only certain types of vibrations could travel through the material. Received ... >>

Random news from the Archive

Building material from plastic waste 19.11.2009

Recycling of plastics is a serious problem, even when it comes to thermoplastics, which, it would seem, are easy to melt into new products. Discarded plastic bottles, cans, bags, toys, etc. must not only be washed from contamination, but also sorted into types of plastics, paper and metal inclusions are separated, which greatly raises the cost of recycling.

However, a factory has recently opened in England where polymer waste is simply crushed and pressed when heated into sheets that resemble plywood or chipboard in properties and at about the same price. They can be used as roofing material, floor covering, billboards, fencing and fence material.

A factory with a capacity of 360 sheets of new material per year operates in the city of Luton near London, and it is planned to open the same production facilities in ten more cities so that polymer waste is not transported far.

About five million tons of various plastics are used annually in Britain, and less than one-fifth is recycled.

Other interesting news:

▪ Following in the footsteps of garbage

▪ Wearable biosensors from old CDs

▪ The world may go coal-free

▪ SilverStone LSB02 backlight controller for PC

▪ LCD TV with hard drive and DVD recorder

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Application of microcircuits. Article selection

▪ article Stationary walk-behind tractor. Drawing, description

▪ article In which war was one of the rounds of negotiations devoted to limiting the size of flags? Detailed answer

▪ article Locksmith for the repair and maintenance of machinery and equipment. Standard instruction on labor protection

▪ article Use of solar energy. Encyclopedia of radio electronics and electrical engineering

▪ article Conceived number. Focus secret

Leave your comment on this article:

All languages of this page

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