Light switch: remote control and timer. Scheme, description

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Light switch: remote control and timer. Encyclopedia of radio electronics and electrical engineering

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Encyclopedia of radio electronics and electrical engineering / Lighting

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This device can be installed indoors instead of a conventional wall light switch. This will allow you to turn on or off the light not only manually, but also remotely, by giving commands from any IR remote control operating according to the RC-5 protocol. By pressing the switch button in a certain order or using the same remote control, you can set the time (from 5 to 60 minutes), after which the lighting will be automatically turned off. The switch is suitable for controlling any type of lamps, including fluorescent ones.

The electronic components of the proposed switch are powered by a 220 V network. However, it is very economical. The power consumed in standby mode (with the lights off) does not exceed 0,35 V-A. The total power of the lamps controlled by the switch can reach 1000 W.

Although the IR receiver of the switch is hidden in its plastic housing, the remote control range is up to 6 m. If necessary, it can be doubled by ensuring that the IR rays penetrate unhindered to the receiver, for example, by drilling a hole in the housing.

Light switch: remote control and timer
Fig. 1

The switch circuit is shown in fig. 1. Its main node - microcontroller DD1 - works according to the program, the codes of which are given in the table. The program was developed using the BASCOM-AVR compiler version 1.11.8.3. Manual control of the circuit breaker is performed using the buttons SB1 and SB2. If desired, two buttons can be connected to the XP1 connector, duplicating the main ones. The length of the connecting wires going to them can reach 10 m.

The IR receiver module B1 receives remote control commands. The microcontroller decodes them, selects those intended for the device with code 0 (TV), and executes them according to the program. Transistor VT1, according to the signals of the microcontroller, controls relay K1, the contacts of which are included in the power circuit of lighting lamps. LEDs HL1 and HL2 indicate different modes of operation of the circuit breaker. The power supply unit of the device consists of a step-down transformer T1, a diode rectifier bridge VD1 and a voltage regulator DA1.

Light switch: remote control and timer
Fig. 2

The device is assembled in a case from a conventional wall switch "Prima". All parts are placed on a printed circuit board, the drawing of which is shown in Fig. 2. All resistors and capacitors (with the exception of oxide ones) are size 0805 for surface mounting. They are installed on the side of the printed conductors. The rest of the parts are mounted in the usual way. The printed conductors connected to the contacts of relay K1 must be covered with a layer of solder about 1 mm thick, which will prevent them from overheating by the load current.

Relay K1 - Bestar BS-115C 12VDC with contacts capable of switching current up to 10 A at an alternating voltage of 240 V. Transformer T1 - Hahn BV-201 0136 with a winding voltage of II9 V. The relay and transformer can be replaced with others that are suitable for the characteristics, but printed in this case, the board will probably have to be redone.

The TSOP1736 IR receiver after mounting on the board must be tilted towards the microcontroller installed on it, so that the direction of its maximum sensitivity to IR rays is almost perpendicular to the plane of the board. To the foil area, indicated in Fig. 2 by the letter A, solder the MXNUMX nut for the screw fastening the parts of the switch housing. Holes are drilled in the case for LEDs.

Light switch: remote control and timer

On fig. 3 the assembled board is shown mounted on a 4 mm thick plastic base. In it (under the board) there are holes for connecting wires and for fastening to the wall. On the inside of the switch key, as shown in Fig. 4, the bracket is fixed. In the assembled device, it touches the pushers of the buttons SB1 and SB2, causing them to fire when a key is pressed.

Light switch: remote control and timer
Fig. 3

Immediately after the supply voltage is applied, both LEDs flash five times, which indicates normal operation of the device. Then the HL2 LED (green) turns on. The winding of relay K1 remains de-energized, and the lighting is turned off.

The light is turned on by pressing the SB1 ("On") button or by giving the "Channel +" command from the remote control. Simultaneously with the operation of the relay, the HL2 LED will go out, and HL1 (red) will be turned on. To turn off the light, just press the button SB2 "Off." or give the command "Channel -". The device will return to standby mode.

Lighting turns on and when you press the buttons "1" - "6" on the remote control. However, at the same time, a timer starts to work, which automatically turns off the light after a specified time. The shutter speed depends on which remote control button was pressed: "1" - 5 minutes, "2" - 10 minutes, "3" - 20 minutes, "4" - 30 minutes, "5" - 45 minutes, "6" - 60 min. When the timer is running, both LEDs are on. 4 s before the expiration of the exposure, the red LED will flash four times, then the light will turn off and the device will go into standby mode.

To turn on the timer without the remote control, just hold the "On" button. pressed for more than two seconds until the green LED starts flashing. However, in this case, only two exposures are possible - 5 and 30 minutes. The first is set by briefly pressing the "On" button. during the blinking of the LED, the second - by its long (more than 2 s) pressing. If within 30 seconds the "On" button not pressed, the timer mode will be cancelled. Before the expiration of the time allotted for programming, the timer can be turned off by pressing the "Off" button. or the remote control command "Channel -". Since the light remains on after exiting the timer programming mode, you will need to issue these commands again to turn it off.

The circuit board file of the switch (in Sprint Layout 4.0 format) and the microcontroller program can be downloaded hence.

Author: L. Aristov, Barnaul, Altai Territory; Publication: radioradar.net

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