During the operation of classic light switches in offices and residential buildings, they quite often fail. This situation is due to the presence of rubbing parts. Today, such devices are increasingly being replaced by more reliable and high-quality models of touch switches. The principle of operation and design of these products are distinguished by their simplicity and affordability. Due to this, even a beginner can make a touch device with his own hands.
Design
To make a touch switch with your own hands, you need to understand that the feature of this product is that for an ordinary user it is enough to touch a certain contact field with his fingers, and he will get the same result as when working with a standard keyboard unit. But the principle of operation of an improved device has its own differences. Most often, the design of the touch device is based on four working nodes:
- electronic circuit board;
- protection panels;
- case;
- contact sensor sensor.
There are several common models that differ in durability, reliability, quality and appearance. The wizard can try to create a do-it-yourself touch switch with a dimmer. There are options that monitor the temperature in the room, as well as raising the blinds on the windows.
Principle of operation
Before proceeding with the manufacture of a touch switch with your own hands, you need to consider the operation scheme of the device. The electronic part is most often represented by a cascade amplifier that processes the signal coming from the main panel. It is this node that raises the amplitude of the incoming wave to the desired level. This option is relevant for switching small current loads. The statistical electricity available on the human body is enough to open the input transistor. Manufacturers often install three cascades at once, in order to eventually achieve the desired ratio. If the master wants to make a touch switch with his own hands, then a load relay can be included in the general circuit (instead of the classic resistor). Such a product is better and more reliable.
Benefits
Classic and loop-through touch switches boast numerous positive features. The main ones include:
- Silent operation of the main executive module, which is built into the switch.
- The practicality of the established switching scheme.
- Complete safety of operation of the product, since power is supplied through galvanic isolation.
- A modern look that will fit into any interior.
It is worth noting that advanced products can be touched even with wet hands, which is not recommended for keyboard devices. Setting up the touch switch is not a complicated process, thanks to this the master can understaff the mechanism with a remote control system.
Functionality
Setting the touch switch compares favorably with the fact that another useful function is added to the device - the built-in timer. Due to this, users can control the switch programmatically. For example, independently set the on and off time. If desired, you can also supplement the device with an acoustic sensor. In this case, the unit will function as a kind of controller for noise and movement. The user only needs to cast a voice or clap his hands loudly, and the light in the room lights up. If you need to adjust the brightness, then you should additionally install a dimer. Due to this, it will be possible to control the intensity of the light flux. Having studied the basic scheme, you can figure out how to make a touch switch without unnecessary financial investment.
Interconnection of mechanisms
To correctly connect the touch switch, you need to know what each node is responsible for. The classic device operates as follows:
- A weak signal is formed on the sensitive element, which is fed to the input of the installed microcircuit. At this point, the incoming information wave is amplified to the desired value, after which it is fed through the transistor to the control electrode of the triac. All manipulations are performed in fractions of a second.
- The opening time of the output control element is regulated depending on the duration of the transistor.
- If the user holds his fingers on the switch for a long time, then the current in the supply circuit will rapidly increase. In such a situation, the illumination in the room will also increase.
- To turn off the light, you need to keep your fingers on the sensor and after reaching the maximum brightness of the light flux.
If a beginner wants to understand how the sensor works, then he needs to study in detail the classic circuit of the unit. For self-production of sensitive areas, you can use ordinary copper foil.
Connection Rules
The installation of the touch switch corresponds to the classical scheme, which is intended for keyboard products. Almost always on the rear panel there are two terminal contacts: under load and input. High-quality switching in the product circuit is carried out on a phase line. A conductor is supplied to the input, and the voltage for the load is removed at the output. In some cases, the design may consist of several independent sections. Because of this, the number of terminals to connect increases. In order not to get confused, you need to follow the classical scheme. The design of the circuit breaker is made in such a way that it fits freely in traditional socket boxes. The chassis is fixed with strong screws.
Homemade devices
When the master has studied the principle of operation of the touch switch, he can try to make the device with his own hands. In this case, you can save a pretty decent amount, since the finished device costs at least 2 thousand rubles. If the master has minimal skills in electrical engineering, then it will not be difficult for him to build a touch switch. The main thing is to prepare in advance all the necessary tools and materials.
Elementary option on relays and transistors
This method will be mastered even by a beginner. A wizard can apply almost any relay. The basic requirement is that the operating voltage range should be between 5 and 12 volts. The unit must switch the load in the 220 V network. The touch switch is made by carefully cutting the getinax from a sheet of foil. Transistors can be any series. Experts note that this circuit is represented by a classic signal amplifier. When you touch the surface of the sensitive sensor, a potential appears on the basis of the transistor, which is quite enough to open the emitter-collector junction. After that, the voltage is supplied to the relay coil. The device works, and the contact group closes, which leads to the inclusion of light.
Application of infrared sensor
This element can be safely used to make a universal switch. According to the scheme, the master can also use inexpensive electronic mechanisms. It is worth noting that, in terms of complexity, this option is designed for experienced professionals. As a base, you need to use two microcircuits, as well as the following details:
- photodetector;
- ordinary LED;
- relay;
- infrared LED.
A pulse generator will help to assemble an inverter chip. If a biological object appears in the zone of the infrared LED, the pair of infrared LED and photodetector instantly triggers. Based on the classic transistor, a control signal is generated, which turns on the relay. If active movement in the sensor coverage area does not occur, then after 20 minutes of inactivity the counter will count a certain number of pulses from the flashing LED, which is enough to turn off the relay. The lamp goes out. It should be noted that the waiting time is determined by the selection of circuit elements.
Trigger Versatility
Most touch switch circuits are simple and affordable. In the circle of hams, microcircuits are the main link in a device that you can assemble yourself. The state of the trigger can be changed by applying a control signal to its output. It is this property that has been successfully used to implement the switch function. The universal output circuit is built with the addition of a field effect transistor. It is this unit that provides high sensitivity, as well as qualitatively isolates contacts. The main element of the sensor can be independently made from a metal plate and connected to the input of the field controller. Due to this, it will be possible to guarantee complete safety of the unit for the end user in terms of possible electric shock. A universal transistor can amplify the existing signal that comes from the chip. The thyristor plays the role of a multifunctional switch. The lighting device, which also needs to be controlled, is necessarily included in the circuit. The scheme operates as follows:
- First of all, the user touches the installed metal plate (sensor).
- Created static electricity enters the input.
- Using a field effect transistor, the trigger is switched.
- The output signal is amplified to the desired performance.
- The thyristor opens.
- The lamp lights up.
If the user again touches the sensor with his hand, then all operations will be repeated, but only in the reverse mode switching. Everything is quite simple and effective. Such a circuit can be used to control luminaires where the total power of incandescent lamps is within 80 watts. If you need to switch more powerful mechanisms, then you should include a cooling radiator in the circuit.