All buildings have areas which are in darkness during day time. In such locations we can use a solar day lamp. The lamp will turn ON when the sun rises and will turn OFF when the sun sets. There are no switches to be turned on or off. It will convert the previously dark area into perpetually bright area through out the day.
The total cost of this lamp will be about 700 Indian rupees.
Step 1: Material required for making solar day lamp
You need following material (see figures)
1. Aluminum Channel
2. Wooden batten
3. Wood screws 0.5” long
4. Plastic or fiber washers 3 mm inner diameter
5. 5 White LEDs 1W rating
6. 3 Way terminal strip and mounting screw/nut.
7. Solar PV panel 12V 5 W
Step 2: Circuit diagram of the solar day lamp
The circuit diagram of a very simple day lamp is shown in the figure. It consists of a Photovoltaic (PV) panel of 12 Volts 5 Watt rating. The positive terminal of this panel is connected to a 15 ohms 2 watt resistor. The other end of this resistor is connected to the anode (+) terminal of LED1. The cathode (-) terminal of LED1 is connected to anode of LED2 etc. Thus 5 LEDs are connected in series as shown in the circuit diagram. The cathode terminal of LED5 is connected to the negative terminal of the PV panel.
Step 3: Aluminum channel with âTâ slots and wooden batten
Take an aluminum channel of 1” x 0.5” dimension as shown in the figure. It should have “T” slots cut. (Such channels are easily available in hardware shops). Cut this aluminum channel such that there are 5 “T” slots and one hole each at both the ends. Remove burr from edges and from “T” slots and clean the channel. Take a wooden batten of 10 mm X 10 mm size. Cut batten so that it’s length covers all 5 “T” slots and hole at one end as shown in figure.
Step 4: Marking the wooden batten (1)
Place the wooden batten centrally inside the channel and mark the holes.
Step 5: Marking the wooden batten (2)
Draw center lines for the marked holes. Also at a distance of 23 mm from center of each mark, draw a + sign.