Mostly, everyone of us know that when electrical power is supplied to a DC motor, it rotates but only a relatively few people know that when the motor shaft is rotated with hands, electrical power is generated at the motor terminals.
In this instructable, i have decided to use the above said principle to make a hand operated Flashlight a home. A 12v DC motor is used to power a panel of 9 LEDs connected in a parallel configuration. This flashlight will never require any batteries to operate.
Step 1: Order Parts
- 12v DC Motor - https://rover.ebay.com/rover/1/711-53200-19255-0/1...
- LED's - https://rover.ebay.com/rover/1/711-53200-19255-0/1...
- Hot Glue Gun - https://rover.ebay.com/rover/1/711-53200-19255-0/1...
- Soldering Iron - https://rover.ebay.com/rover/1/711-53200-19255-0/1...
- Stationary Knife - https://rover.ebay.com/rover/1/711-53200-19255-0/1...
- 12v DC Motor - http://amzn.to/2fbh0oi
- LED's - http://amzn.to/2sAFYOT
- Hot Glue Gun - http://amzn.to/2vQEINI
- Soldering Iron - http://amzn.to/2r3IX6g
- Stationary Knife - http://amzn.to/2q879jK
- 12v DC Motor - http://amzn.to/2vAmO1h
- LED's - http://amzn.to/2sAQx4t
- Hot Glue Gun - http://amzn.to/2rjNE9r
- Soldering Iron - http://amzn.to/2qC47qG
- Stationary Knife - http://amzn.to/2q1kb6M
From Home & Local Store: 2 x Spare CD, 2 x Bottle caps, small Plastic Bottle, wooden stick, Aluminium Foil and connecting wires.
Step 2: Build Flashlight Reflector
- Take a small Plastic bottle and cut the bottle into two pieces as can be seen in the attached images.
- Place the head of the bottle on a spare CD.
- Using a permanent marker, make a circle around the bottle head.
- Cut the CD along the marked lines to get a small circular disk.
- Drill a hole at the center of the disk.
- Make 8 holes around the center hole, equidistant from each other. Be extra cautious while drilling holes as excessive force will break the entire disk.
Note: The shining polish from the CD surface will act as the reflector for the LEDs.
Step 3: Build LED Panel
- Apply hot glue and insert LEDs in the holes made on a circular disk.
- Secure the LEDs well by applying hot glue at the back.
- Refer to the schematic attached above and connect all the 9 LEDs in parallel configuration as shown.
- Solder two wires at the LED terminal for '+ve' and '-ve' connection. Note: I have not used any resistor in connection with LEDs as the motor i used just provides sufficient power, however, to be on a safe side it is recommended to connect a 10 ohm resistor in series with the LED panel and the '+ve' terminal wire.
- Take the half cut bottle head we used earlier and open the bottle cap.
- Wrap the bottle head completely in a piece of food wrapping aluminium foil as shown in the attached image.
- Insert the LED panel inside the bottle half and secure it with hot glue.
Our flashlight is almost ready. The shiny silver surface from the disk and the aluminium foil will act as a good reflector for LED light.
Step 4: Build Rotating Mechanism
- Take a spare CD and remove the label from the CD to get a clear transparent disc (optional step).
- Using Hot glue, paste a bottle cap at the center of the CD.
- Flip the CD and paste another bottle cap near the outer boundary, as can be seen in the attached images.
- Drill a hole at the center of both the both the bottle caps.
- Fix the motor shaft of a 12v DC motor in the bottle cap at the center.
- Fill hot glue in the bottle cap to secure the motor shaft.
- Take a wooden stick of about 10 cm and insert it in the hole of other bottle cap.
- Fill hot glue in the bottle cap to secure the wooden stick.
Step 5: Connect LEDs and Handle
- Connect a multimeter in DC voltmeter range to the motor terminals.
- Rotate the motor shaft using the wooden stick and observe the polarity of the motor terminals with respect to the direction of rotation.
- After observing the correct polarity, solder the wires from the LED panel to the motor terminal.
- Using Hot glue, attach the flashlight on the DC motor in such a way that it doesn't hinder the rotating movement of the disc.
Step 6: Test Flashlight
Our DIY Hand operated Flashlight is now ready. Take the flashlight to a dark environment and rotate the motor shaft at a uniform speed, you will find that the flashlight works really well without any need to connect batteries ever.
So friends, this here concludes the instructable, stay tuned and follow me to receive regular updates. Don't forget to leave your valuable suggestions in comments section below.
Thanks For Your Support..!!