Infrared Based Power Saving Light

Quite often you forget to switch off the light or fan when going out of the room. The simple infrared sensor based power saver circuit presented here will automatically switch off electrical appliances like lights or fans as you vacate a room, after a predetermined time period. It will also switch on the light when you enter the room again. This will reduce unnecessary power consumption. This is very simple and cost effective circuit which installed gives us a gain in unnecessary power loss and money.

The sensor is a device that is used to detect the changes in events or quantities and it produces approximate outputs. An infrared sensor is an electronic device that is used to measure the heat of an object and also detects the motion. It can emit and in order to sense some aspects of the surroundings. Rather than emitting it, these types of sensor measures only infrared radiation, so it is known as a passive IR sensor

here describes of the infrared sensor based power saver circuit, which consists of the following block, power supply, IC555, transistor driver, relay, bulb & PIR sensor.The circuit diagram of the infrared sensor based power saver. It is built around bridge rectifier DB107 (BR1), PIR motion sensor connected across connector CON2, timer NE555 (IC1), two 1N4007 rectifier diodes (D1 and D2) and a few other components.

The circuit uses a PIR sensor, which detects the presence of people through change in the infrared radiation from the room when people enter or leave the room. The PIR sensor outputs around 3.3V high signal whenever it detects radiation change in front of it.

POWER SUPPLY

A power supply is an electrical device that supplies electric power to an electrical load. The primary function of a power supply is to convert electric current from a source to the correct voltage, current, and frequency to power the load. As a result, power supplies are sometimes referred to as electric power converters. Some power supplies are separate standalone pieces of equipment, while others are built into the load appliances that they power. Examples of the latter include power supplies found in desktop computers and consumer electronics devices. Other functions that power supplies may perform include limiting the current drawn by the load to safe levels, shutting off the current in the event of an electrical fault, power conditioning to prevent electronic noise or voltage surges on the input from reaching the load, power-factor correction, and storing energy so it can continue to power the load in the event of a temporary interruption in the source power.

IC 555

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element. Derivatives provide two (556) or four (558) timing circuits in one package.

Introduced in 1972 by Signetics,the 555 is still in widespread use due to its low price, ease of use, and stability. It is now made by many companies in the original bipolar and in low-power CMOS technologies. As of 2003, it was estimated that 1 billion units were manufactured every year. The 555 is the most popular integrated circuit ever manufactured.

RELAY

A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof.

Relays are used where it is necessary to control a circuit by an independent low-power signal, or where several circuits must be controlled by one signal. Relays were first used in long-distance telegraph circuits as signal repeaters: they refresh the signal coming in from one circuit by transmitting it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations.

LOAD

We can connect any electrical equipment as load to the circuit. Here we are using a bulb as the load.

PIR SENSOR

A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors. PIR sensors are commonly used in security alarms and automatic lighting applications. PIR sensors detect general movement, but do not give information on who or what moved. For that purpose, an active IR sensor is required.

The circuit diagram of the infrared sensor based power saver is shown in Fig. 2. It is built around bridge rectifier DB107 (BR1), PIR motion sensor connected across connector CON2, timer NE555 (IC1), two 1N4007 rectifier diodes (D1 and D2) and a few other components.

The circuit uses a PIR sensor, which detects the presence of people through change in the infrared radiation from the room when people enter or leave the room. The PIR sensor outputs around 3.3V high signal whenever it detects radiation change in front of it.IC1, resistor R3, potentiometer VR1 and capacitor C3 are used as a timer here to convert small time span of PIR signal to a long delay. Output of IC1 at pin 3 drives transistor T2, which, in turn, controls relay RL1. Electrical loads like lights or fans are controlled through this relay.

When the circuit is first switched on, capacitor C3 charges through potmeter VR1 and resistor R3. During this time, voltage at pins 2 and 6 of IC1 is less than two-thirds of its

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supply voltage, and so output pin 3 goes high. This energises the relay through transistor T2, and the appliance is switched on.

When capacitor C3 charges above two-thirds of the supply voltage, IC1’s output pin 3 goes low and de-energises the relay and switches off the appliance after some delay that can be adjusted through potmeter VR1.

Whenever motion is detected by the PIR, its output pin goes high (around 3.3V) for a while depending on the setting on the PIR. The high signal from the PIR is fed to the base of transistor T1, which, in turn, discharges capacitor C3 through resistor R4. When the capacitor’s charge (voltage) reaches less than two-thirds of the power supply, output pin 3 of IC1 goes high again (initial stage) and load is switched on.When the load is switched off, LED2 glows. This indicates that the circuit is under power-save mode.

A single-side PCB for the PIR sensor based power saver is shown in Fig. 3 and its component layout in Fig. 4. Enclose the PCB in a small box in such a way that you can easily connect 230V AC input to CON1 and the light/fan to CON3 at rear end of the box. Connect the PIR using a 3-wire cable to the PCB at CON2 and install it at a suitable location in your room.Before using the PIR in the circuit, manually check it by connecting Vcc and GND pins of PIR to a 9V (or 12V) battery. Then check for change in voltage at signal output pin with respect to ground by waving your hand in front of the sensor. Adjust sensitivity and time controls of the PIR as per requirement (else turn both presets clock-wise to have highest sensitivity and high time signal). The dome surface of the PIR should be clean for better sensing.

You need to generate a UV translucent artwork film. you will never get a good board without good artwork, so it is important to get the best possible quality at this stage. The most important thing is to get a clear sharp image with a very solid opaque black. Nowadays, artwork is drawn either using either a dedicated PCB CAD program or a suitable drawing/graphics package. It is absolute essential that your pcb software print holes in the middle of the pads, which will acts as centre marks when drilling. It is virtually impossible to accurately hand drill boards without these holes. The artwork must be printed such that the printed side in contact with pcb surface while exposing, to avoid blurred edges. In practice, this means that if you design the board as seen from the component side, the bottom layer should be printed the ‘correct’ way round, and the top side of double sided board must be printed mirrored.

1.MEDIA

Artwork quality is very dependent on both the output device and media used. It is not necessary to use a transparent artwork medium as long as it is reasonably translucent to UV, its fine-less translucent materials may need slightly longer exposure time.

2.OUTPUT DEVICES

Laser printers offer the best aa round solution. These are affordable, fast and good-quality. The printer used must have at least 600dpi resolution for all but the simplest PCBS , as you will usually be working in multiles of 0.06cm. 600dpi divides into 40, so you get consistent spacing and line width, it is very important that the printer produces a good solid black with no toner pinholes.

3.PHOTO RESIST PCB LAMINATES

Always use good quality, pre-coated photo resist fiberglass board. Check carefully for scratches in the protective coating and on surface after peeling of the covering, You don’t need darkroom or subdued lightning when handling boards, as long as you avoid direct sunlight, minimize unnecessary exposure, and develop immediately after UV exposure.

4.EXPOSURE

The photo resist board needs to be exposed to UV light through artwork, using a UV exposure box. UV exposure units can easily be made using standard fluorescent lamp ballasts and UV tubes. For small PCBs, two or four 8-Watt, 30.5cm tubes will be adequate.

5.DEVELOPING

Do not use sodium hydroxides for developing photo resists laminates. It is a completely and utterful dreadful stuff for developing PCBs. Apart from its causticity,it is very sensitive to temperature and concentration, and made-up solution doesn’t last long.

6.ETCHING

Ferric chloride etchant is a messy stuff, but easily available and cheaper than most alternatives. It attacks any metal including stainless steel. So when setting up a PCB etching area, use a plastic or ceramic sik, with plastic fittings and screw whenever possible, and seal any metal screws with silicone. Copper water pipes may get splashed or dripped-on, so sleeve or cover them and plastic; heat-shrink sieving is great if you’re installing new pipes. Fume extraction is not normally required, although a cover the tank or tray when not in use is a good idea. You should always use the hex hydrate type of ferric chloride, which should be dissolved in warm water until saturation. Adding a teaspoon of table salt helps to make the etchant clearer for easier inspection. Avoid anhydrous ferric chloride.

7.TIN PLATING

Tin-plating a PCB makes it a lot easier to solder, and is pretty much essential for surface mount boards. Unless you have access to roller tinning machine, chemical tinning is the only option. Unfortunately, tin-plating chemicals are expensive but the results are usually worth it. If you don’t tin-plate the board, either leave the photo resist coating on or spray the board with network flux to prevent the copper from oxidizing.

8.DRILLING

If you have fibre glass board, you must use tungsten carbide bits. Fiberglass eats normal high-speed steel bits very rapidly, although HSS drills are all right and thin ones sap very easily. When using carbide drill bits below 1mm, you must use a good vertical drill stand-you will break drill very quickly without one.

9.CUTTING

A small guillotine is the esiest way to cut fiberglass laminate. Ordinary saws will be blunted quickly unless these are carbide-tipped, and the dust can cause sink irritation.

10.SOLDERING

Soldering is the joining of two metals together to give a physical bonding and good electrical connectivity. It is used primarily in electrical and electronics circuitry. Solder is a combination of metals, which are solid at normal room temperatures and become liquid between 180 and 200 degree celsius. Solder bonds well to various metals, and extremely well to copper.

Soldering is necessary skill you need to learn to sucsessfully build electronics circuits. It is primary way how electronics components are connected to circuit boards, wires and sometimes directly to other components.

1. This circuit help us to save unnecessary electricity loss.

2. It is a low cost circuit.

3. It is simple and it can be installed without any complexity.

4. As long as the person is in sensing area, switch can be kept on continuously

1. By using this we can save unnecessary electricity loss

2. By connecting an alarm, this circuit awares us of any intruder coming.

1. PIR is highly sensitive, so it can damage easily.

2. It is easily interfered by various heat source resources.