How to Make Your Own LED Bike Light

Make an LED bike light yourself and customize it.

Whether riding your bike at night or in the daytime, visibility is essential for the rider who must be able to see obstacles in his or her path and for the surrounding drivers and pedestrians. Modern LED lamps are small, lightweight, bright and energy-efficient, making them ideal for bicyclists. Building your own bike lamps will save you some money and allow for much greater customization than purchasing commercially manufactured lamps.

Things You'll Need

• Wire cutter
• Wire strippers
• Super-bright 5mm LED
• LED lamp assembly with lens
• 1-inch PVC end cap
• Push button on/off switch
• Epoxy cement
• 82 ohm .05 watt resistor
• Electrical wire
• 4 C-cell batteries
• Battery holder
• Large project enclosure
• Electric drill
• Drill bits
• Soldering iron
• Flux-core solder
• Wire cutters
• Electrical tape
• Toothpick or small nail

Instructions

Wiring the Lamp

1. Cut two pieces of electrical wire approximately 3 feet long with a wire cutter and label one wire with a "+" sign and the other with a "-" sign to indicate which is positive and which is negative.

2. Strip 1/4 inch of the insulation from one end of the positive wire, using wire strippers, and attach it to one of the metal leads protruding from your resistor. Use your soldering iron to heat up the area where the wire connects to the resistor and touch the tip of your flux core solder to the connection point, solidifying the connection. Wrap the connection point and as much of the exposed circuit as possible with electrical tape.

3. Slide the tip of your LED into the bottom of your lamp assembly and screw on the retaining ring to lock it in place. Find the positive end--the longer of the two leads coming from the bottom of your LED. Connect the positive end of your LED to the open end of your resistor and then solder the connection. Wrap the exposed circuit in electrical tape.

4. Strip 1/4 inch of insulation from your negative wire and connect it to the negative end of your LED (the shorter of the two leads). Solder the connection in place and insulate the exposed circuit with electrical tape.

5. Put your C-cell batteries in the battery holder and connect the positive wire to the positive terminal and the negative wire to the negative terminal on the battery holder, completing the circuit and causing the LED to light up.

Assembling the Lamp Enclosure

1. Bore two holes through the end of your 1-inch PVC end cap, using the drill and a bit with the same approximate diameter as your insulated wire. Thread the positive and negative wires through each respective hole.

2. Pull the wires through the holes so that the lamp rests on the rim of the PVC end cap with the circuitry entirely enclosed inside. Mix equal parts of epoxy cement and cement hardener for 30 seconds and apply a thin coating to the inside and the rim of the PVC end cap. Press the lamp assembly down onto the end cap until the glue has set.

3. Place a drop of epoxy cement over the wire holes in the PVC end cap with a toothpick or small nail, coating the outside of the wire as well. This will make a watertight seal and prevent the wires from being easily ripped out.

Assembling the Battery Enclosure

1. Unscrew the face plate on your project enclosure. Mix a small amount of epoxy cement and apply it to the back of your battery holder. Place the battery holder inside the project enclosure and apply pressure until it is firmly glued to the back of the enclosure.

2. Drill a hole through the side of your project enclosure, using a drill bit the same size as the threaded shank on your push-button switch. Leave enough space in the enclosure so that when the switch is installed you are still able to easily remove and replace the C-cell batteries. Slide the switch's shank through the hole and screw on the retaining ring to secure it in place.

3. Drill two more holes in the project enclosure large enough for your electrical wires. Thread the positive wire through the first hole and connect it to the positive terminal on your battery case.

4. Thread the negative wire through the other hole and connect the end of it to one of the open terminals on your push-button switch. Solder the connection.

5. Cut a very small piece of electrical wire and strip both of the ends. Connect one of the wire to the negative terminal on your battery case. Connect the other end of the wire to the open terminal on your push-button switch and solder the connection, completing the circuit. Test the circuit by pressing the push-button switch to the "on" position. If the circuit works and the light comes on, screw the face plate back on to your project enclosure.

Tips & Warnings

• Use hose clamps to secure your lamp assembly to the handlebars of your bike and then run the wires along the frame to your battery enclosure, which can also be secured with hose clamps to the frame of the bike.

References

• Metku.net: Current Limiting Resistor Calculator
• TheLEDLight.com: LED Circuitry Tutorial