Introduction: Emergency Spin-it LED Flashlight
Introduction
In emergency a small light source is a must. You may need it to find a more reliable light source like an operational flashlight. This flashlight is built around a super capacitor and a DC motor. Super caps can store up energy fast and release it slowly. These features plus their compactness make them so useful to build emergency flashlights. One can say: Hey, there are quite a few “shake-it” and “pump-it” models available at reasonable prices. That’s true, but my flashlight is a bit different. 1- minute finger spinning gives 5-minute lighting. You may opt to charge this flashlight with a string loop.
Time: 1 hour
Cost: low
Difficulty: easy
In emergency a small light source is a must. You may need it to find a more reliable light source like an operational flashlight. This flashlight is built around a super capacitor and a DC motor. Super caps can store up energy fast and release it slowly. These features plus their compactness make them so useful to build emergency flashlights. One can say: Hey, there are quite a few “shake-it” and “pump-it” models available at reasonable prices. That’s true, but my flashlight is a bit different. 1- minute finger spinning gives 5-minute lighting. You may opt to charge this flashlight with a string loop.
Time: 1 hour
Cost: low
Difficulty: easy
Step 1: Materials and Tools
Materials and Tools
You need:
1. A small plastic bottle. Mine is a container for vitamin C pills. It is large enough to accommodate a DC motor and other parts.
2. DC motor. Mine is a 9V motor salvaged from an old cassette recorder.
3. a short length of insulated wire.
Electronic parts: 1 super capacitor (1F/5.5V), 1 super bright 5mm white LED(50cd), 1 – 24 Ohm/0,25W resistor (red-yellow-black), 1 Schottky diode (1N5819), a micro slide switch (3-pin).
Tools:
Wire cutters
Tweezers
Soldering iron
Drill and drill bits (optional)
Solder
You need:
1. A small plastic bottle. Mine is a container for vitamin C pills. It is large enough to accommodate a DC motor and other parts.
2. DC motor. Mine is a 9V motor salvaged from an old cassette recorder.
3. a short length of insulated wire.
Electronic parts: 1 super capacitor (1F/5.5V), 1 super bright 5mm white LED(50cd), 1 – 24 Ohm/0,25W resistor (red-yellow-black), 1 Schottky diode (1N5819), a micro slide switch (3-pin).
Tools:
Wire cutters
Tweezers
Soldering iron
Drill and drill bits (optional)
Solder
Step 2: Schematic
Schematic
There are only 5 electronic parts : a super bright 5mm white LED (50cd), a resistor (24 Ohm), a Schottky diode (1N5819), a super capacitor (1F/5.5V), a micro slide switch (3-pin). The resistor limits the current flowing across the LED. The diode prevents discharging across DC motor’s windings.
There are only 5 electronic parts : a super bright 5mm white LED (50cd), a resistor (24 Ohm), a Schottky diode (1N5819), a super capacitor (1F/5.5V), a micro slide switch (3-pin). The resistor limits the current flowing across the LED. The diode prevents discharging across DC motor’s windings.
Step 3: Prototyping
Prototyping
Solder the parts according to the schematic. Be sure the switch is off. Spin the rotor shaft with your thumb and index finger. Be patient. It takes about a minute to charge the super capacitor. Switch on and check how long it works.
Solder the parts according to the schematic. Be sure the switch is off. Spin the rotor shaft with your thumb and index finger. Be patient. It takes about a minute to charge the super capacitor. Switch on and check how long it works.
Step 4: Making the Enclosure
Making the enclosure
Remove the label and grease from the plastic bottle. Make a hole in the bottom. I used a hot electric wire and a file to do the job, but you may drill. The diameter should be equal to the diameter of your DC motor’s body. Make a hole right in the center of the bottle cap (5mm in diameter to insert the LED). I used a hot nail to do it. Make 3 tiny holes on the bottle neck to install the switch. I used a small hot nail to prick holes. The enclosure is ready.
Remove the label and grease from the plastic bottle. Make a hole in the bottom. I used a hot electric wire and a file to do the job, but you may drill. The diameter should be equal to the diameter of your DC motor’s body. Make a hole right in the center of the bottle cap (5mm in diameter to insert the LED). I used a hot nail to do it. Make 3 tiny holes on the bottle neck to install the switch. I used a small hot nail to prick holes. The enclosure is ready.
Step 5: Assembly
Assembly
Insert the motor and the LED into appropriate holes. Install the switch on the bottle neck. Solder the parts according to the schematic. You are done.
Insert the motor and the LED into appropriate holes. Install the switch on the bottle neck. Solder the parts according to the schematic. You are done.
Step 6: How to Charge With a String Loop
How to charge with a string loop
If you don’t want to be bothered with finger spinning, you may try to charge with a string loop. Take a length of strong string (about 2m.) I think a dental floss will work ideally in this case, but I used what I had at hand. Make a loop and wrap it around the pulley on the rotor shaft. Place the flashlight on flat surface and press it with your foot. Tighten the loop and insert a stick (a pen or a pencil) into the other end. Pull hard downwards on one branch of the loop. Make a dozen of pulls and your flashlight is charged. By the way, string is a must in any survival kit.
If you don’t want to be bothered with finger spinning, you may try to charge with a string loop. Take a length of strong string (about 2m.) I think a dental floss will work ideally in this case, but I used what I had at hand. Make a loop and wrap it around the pulley on the rotor shaft. Place the flashlight on flat surface and press it with your foot. Tighten the loop and insert a stick (a pen or a pencil) into the other end. Pull hard downwards on one branch of the loop. Make a dozen of pulls and your flashlight is charged. By the way, string is a must in any survival kit.