AUTOMATIC NIGHT LAMP WITH MORNING ALARM

ABSTRACT:

Automatic Night Lamp with Morning Alarm System is a simple yet powerful concept, which uses transistor as a switch. By using this system manual works are 100% removed. It automatically switches ON lights when the sunlight goes below the visible region of our eyes. This is done by a sensor called Light Dependant Resistor (LDR) which senses the light actually like our eyes. It automatically switches OFF lights whenever the sunlight comes, visible to our eyes and activates the morning alarm. By using this system energy consumption  is also reduced because nowadays the manually operated street lights are not  switched off even the sunlight comes and also switched on earlier before sunset. In this project, no need of manual operation like ON time and OFF time setting. LDR and transistor are the main components of the project. The resistance of light dependant resistor (LDR) varies according to the light falling on it. This LDR is connected as biasing resistor of the transistor. According to the light falls on the LDR, the transistor is operated in saturation and cut off region. This transistor switches the relay to switch on / off the light. This project uses regulated 12V, 750mA power supply. 7812 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/18V step down transformer.

COMPONENTS REQUIRED:

S.NO	COMPONENTS	RANGE/TYPE	QUANTITY
1	IC	IC 7806,IC NE555,UM66	1,1,1
2	Transistor	BC 548	2
3	LDR	-	2
4	Diode	IN4007,IN4001,Zener diode(3.3V,0.5W)	4,2
5	Resistor	1K,150K,120K,220Ω,580Ω,560Ω	2,2,1,1,1,1
6	Capacitor	1000µF,0.01µF	1,2
7	LED	white	1
8	Transformer	230/18V	1
9	Power supply	230V  ac,50Hz	1
10	Battery	9V	1
11	Loudspeaker	-	1

COMPONENT DETAILS:

555 TIMER:

The 555 Timer IC is available as an 8-pin metal can, an 8-pin mini DIP (dual-in-package) or a 14-pin DIP.

This IC consists of 23 transistors, 2 diodes and 16 resistors. The explanation of terminals coming out of the 555 timer IC is as follows. The pin number used in the following discussion refers to the 8-pin DIP and 8-pin metal can packages.

UM 66 :

It is the simplest melody generator circuit you can make using an IC.The  UM66 series are CMOS IC’s  designed for using in calling bell, phone and toys. It has a built in ROM programmed for playing music. The device has very low power consumption.The melody will be available at pin3 of UM66 and here it is amplified by using Q1 to drive the speaker.

IC 7806:

7806 is a 3-terminal positive voltage regulator designed with built in internal current limiting, thermal shutdown and safe-area compensation for maximum flexibility and safety .

With adequate heat sinking provided, USM 7806 can deliver up to 1.5A output current. USM 7806 can be used as fixed voltage regulator in a wide range of applications where local voltage regulation is preferred for elimination of noise and distribution problems associated with single-point regulation. USM 7806 can also be used (by adding external components) to obtain adjustable output voltages and currents.

ZENER DIODE:

A Zener diode is a type of diode that permits current not only in theforwarddirection like a normal diode, but also in the reverse direction if the voltage ilarger than the breakdown voltage known as "Zener knee voltage" or "Zenervoltage". The device was named after Clarence Zener, who discoverethis electrical property

BC548:

 The exact specs of a given device depend on the manufacturer. It is important to check the datasheet for the exact device and brand you are dealing with. Philips and Telefunken are two manufacturers of the BC548.

CIRCUIT DIAGRAM:

click here to download circuit diagram

CIRCUIT EXPLANATION:z

This circuit automatically turns on a night lamp when bedroom light is switched off. The lamp remains ‘on’ until the light sensor senses daylight in the morning. A super-bright white LED is used as the night lamp. It gives bright and cool light in the room. When the sensor detects the daylight in the morning, a melodious morning alarm sounds.

The circuit is powered from a standard 0-9V transformer. Diodes D1 through D4 rectify the AC voltage and the resulting DC voltage is smoothed by C1. Regulator IC 7806 gives regulated 6V DC to the circuit. A battery backup is provided to power the circuit when mains fails. When mains supply is available, the 9V rechargeable battery charges via diode D5 and resistor R1 with a reasonably constant current. In the event of mains failure, the battery automatically takes up the load without any delay. Diode D5 prevents the battery from discharging backwards following the mains failure and diode D6 provides current path from thebattery. The circuit utilises light-dependant resistors (LDRs) for sensing darkness and light in the room.

 The resistance of LDR is very high in darkness, which reduces to minimum when LDR is fully illuminated. LDR1 detects darkness, while LDR2 detects light in the morning. The circuit is designed around the popular timer IC NE555 (IC2), which is configured as a monostable. IC2 is activated by a low pulse applied to its trigger pin 2. Once triggered, output pin 3 of IC2 goes high and remains in that position until IC2 is triggered again at its pin 2. When LDR1 is illuminated with ambient light in the room, its resistance remains low, which keeps trigger pin 2 of IC2 at a positive potential. As a result, output pin 3 of IC2 goes low and the white LED remains off. As the illumination of LDR1’s sensitive window reduces, the resistance of the device increases. In total darkness, the specified LDR has a resistance in excess of 280 kiloohms. When the resistance of LDR1 increases, a short pulse is applied to trigger pin 2 of IC2 via resistor R2 (150 kiloohms). This activates the monostable and its output goes high, causing the white LED to glow.

Low-value capacitor C2 maintains the monostable for continuous operation, eliminating the timer effect. By increasing the value of C2, the ‘on’ time of the white  LED can be adjusted to a predetermined time. LDR2 and associated components generate the morning alarm at dawn. LDR2 detects the ambient light in the room at sunrise and its resistance gradually falls and transistor T1 starts conducting. When T1 conducts, melody-generator IC UM66 (IC3) gets supply voltage from the emitter of T1 and it starts producing the melody. The musical tone generated by IC3 is amplified by single-transistor amplifier T2. Resistor R7 limits the current to IC3 and zener diode ZD limits the voltage to a safer level of 3.3 volts. The circuit can be easily assembled on a general-purpose PCB. Enclose it in a good-quality plastic case with provisions for LDR and LED. Use a reflective holder for white LED to get a spotlight effect for reading. Place LDRs away from the white LED, preferably on the backside of the case, to avoid unnecessary illumination. The speaker should be small so as to make the gadget compact.

ADVANTAGES: 

Highly sensitive

      Works according to the light intensity

        Fit and Forget system

   Low cost and reliable circuit

           Complete elimination of manpower

           Can handle heavy loads up to 7A

          System can be switched into manual mode whenever required

APPLICATIONS

  Bed Rooms

          Hostels and Hotels

          Balcony / stair case / parking Lightings

          Street lights

          Garden Lights

CONCLUSION:

        Thus the working of the automatic night lamp with morning alarm was explained in detail.

ExpressPCB - PCB design software free download

ExpressPCB software is used as PCB designing tool. This is supported by Windows xp, vista and also for windows 7. This software is easy to learn and can also be used simply.This software can be expressed in two ways such as ExpressSCH and ExpressPCB. ExpressSCH is used for drawing schematics and ExpressPCB is used for drawing circuit board layouts.

  The advantage to using their software and mini-board size is that, if desired, you can order professionally made boards, 3 for $59 (the price has varied slightly over the years).

This is a nice deal for robot hobbyists that don’t need production quantity runs. Their boards are of higher quality (greater accuracy, plated through holes, and tin coating) than is usually possible to make at home.

ExpressPCB  is quite good and easy to get started with.

Express schematic  

Express pcb

                    

The disadvantage to using their software is that its breadth of capabilities and components library are somewhat limited, although you can create custom components. Also, you’re stuck with their file format, which is a problem if you want to order production boards from someone else.  

For all the positive reasons, I chose to use the free ExpressPCB software, and I happily continue to do so to this day

click here to download Expresspcb from their website: 
 http://www.expresspcb.com/ExpressPCBHtm/Download.htm

You can see many  Express pcb  video tutorial  from YouTube

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Manufacturing printed circuit board using ferric cloride
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PCB MANUFACTURINNG USING FERRIC CLORIDE

To make the PCB, following materials are required
1. Copper clad board
This is available in different sizes. Select a suitable size to accommodate all the components. If the copper clad board is large in size, cut it to the required size using a Hacksaw blade. The copper clad board has a copper coated side which forms the soldering side. The other side is the component side on which the components are placed.
Copper clad board

2. Ferric chloride solution
This is the Etching solution of Ferric chloride. It removes the unwanted copper layers from the copper clad board. The Etching solution can be prepared by dissolving 50 gms Ferric chloride powder in 100 ml Luke warm water.
3. PCB drill and bits
PCB drill is used to drill holes in the PCB. A hand drill with suitable bits is sufficient for the purpose. Use drill bits of the following size to make holes for different components
A. 1mm – for IC pins
B. 1.2mm – for Resistor, capacitor, transistor etc.
C. 1.5mm – for diode, LED pins, presets etc.
D. 5mm – for LED, nuts, screws etc.
E. 8mm – for switches, pots etc.
4. OHP Permanent Marker Pen, Tracing / Butter paper, Pencil Carbon paper, Varnish etc.
PCB Making
PCB making involves the following stages

1. Draw the circuit diagram as compact as possible on a paper. Mark the points (component pins) to be drilled. This diagram is used for Pattern drawing on the copper clad board.
2. Draw the same diagram in the tracing / butter paper using the OHP marker pen. Draw the diagram carefully without any overlapping or shorting of tracks or components. The neatness of the PCB lies in the Pattern drawing. After drawing, see the other side of the paper. There is a Mirror Sketch of the tracks. This is the actual pattern of the PCB.
Mirror Sketch of PCB tracks

3. Place the Pencil carbon on the copper side of the copper clad board. The ink side of the carbon paper should face the copper layer.
4. Place the tracing paper with diagram over the carbon paper. The diagram should be in the middle part of the copper clad board. Fold the sides of the tracing and carbon papers and stick it using cello tape. This prevents the movement while drawing.
5. Once again redraw the diagram using the OHP marker pen so that the carbon ink will create a mirror sketch on the copper clad board.
6. Remove the tracing paper and carbon paper. Using the OHP marker pen, redraw the carbon pattern of the mirror sketch on the copper laminate. So that the tracks will be created using the permanent marker ink. Keep it for 10 minutes to dry the ink.
7. Mark points to be drilled.
8. Take a Plastic or Porcelain tray and place the copper clad board with the track side facing upwards. Carefully pour the Ferric chloride solution over the copper clad till the copper clad immerse in the ferric chloride solution. Keep the tray in sunlight and shake occasionally. Etching will be completed in one to two hours.
Etched PCB

9. After etching, thoroughly clean the copper clad using tap water. This will remove the dissolved copper from the copper laminate except the copper beneath the OHP pen markings.
10. Drill holes using appropriate drill bits.
11. Remove the OHP pen markings using Petrol or Thinner so that the tracks will appear as copper lines.
12. If required, tin the tracks carefully using solder lead. Dip in varnish to prevent copper oxidation in tracks.
Tinned PCB

Caution: Ferric chloride solution is toxic. It can cause skin burning or irritation. Use hand gloves during etching. Do not spill the ferric chloride on the skin. If this happens accidently, wash with water. Do not keep ferric chloride in places accessible to children.

I read one article about PCB manufacturing in www.printedcircuitboards.com.I just share it with you. 

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