Introduction: Bike LED Lights With Homemade Housings

Picture of Bike LED Lights With Homemade Housings

Using scrap lumber, a 9-volt battery, some LED's, and aluminum foil, make your bike easier to be seen from the side and back.

From the left and right, a yellow light, and from the back, a red light.

After making six identical wood pieces, glue and solder two lights that can be mounted to your bike.

Step 1: Reflector

Picture of Reflector

We are going to be making two of each reflector. Each one is made from 3 identical pieces. So we will be making 6 parts.

Wood supplies:
2x8 lumber, and you only need a little over 1 ft.

Tools:
Tablesaw
tape meas'ure
pencil


Please make sure to use appropriate caution while using power tools.

I used a table saw exclusively for the cuts. Other tools would be better, but since those were not available.

Set the table saw at 5-1/2 inches;
Cut two pieces of the 2x8 at 5-1/2 inches long.

Reset the table saw to 1-5/8;
Taking the two 5-1/2 pieces, cut each one into 4 pieces.
You will now have 8 pieces. We will only be using 6 of them.

Step 2: Reflector - 1st Cut

Picture of Reflector - 1st Cut

Each piece has two sets of cuts. We will be setting the table saw, running all 12 cuts, then resetting the saw and making the next 12 cuts.

These cuts are on small pieces of wood. Please PLEASE make sure to use safety - and common sense. Use a push stick, do not push these pieces through with your hands.

1st cut

For this cut, you will be pushing the piece through standing on its short edge. The way I did this was to use a clamp, two thin pieces of scrap, and one of the extra pieces. Refer to the photos to see how I used these as a handle. I still used a push stick to help push the piece through. The handle does 2 things, helps keep the part from sliding down into the saw, and to help keep the part from tipping as it is sawed.

Set the angle of the blade to 30 degrees.

Set the fence as close to the blade as you feel comfortable. I got mine about 1/8 inch from the blade. Depending on how close this is set, it will vary the size of the end product a bit, but it will also affect the corner finish as well.

Attach the handle. To do this, stand the part on the short edge, right up against the fence. Use the clamp to attach the extra part with the two pieces of thin scrap.

Start the saw and carefully push the piece through.

Release the clamp, flip the piece over, attached the handle and cut.

Repeat for the remaining 5 pieces.

Step 3: Reflector - 2nd Cut

Picture of Reflector - 2nd Cut

These cuts are on small pieces of wood. Please PLEASE make sure to use safety - and common sense. Use a push stick, do not push these pieces through with your hands.

2nd cut

The second cut has to be setup so as when you flip the part over, your second cut does not remove extra material, which will shorten the size significantly.

Set the saw rotation at 45 degrees.

On the part, you will have to locate the center line going the long way, on the short part. Place the part behind the blade and look down the blade to identify the location for the gate.

Lock the gate, and mark or remember the location. We will be making 6 cuts in this position.

Step 4: Reflector - Pre Assembly

Picture of Reflector - Pre Assembly
Tools:
Assorted drill bits around the size of your LEDs
Drill

You should now have 6 identical parts. You can quickly dry fit the parts to verify they actually fit together properly.

You will need a hole through each piece that will allow the LED you purchased to pass through. Take a scrap and drill holes with various sized bits that are close to the size of the LED's Be aware that different ones (my yellow and reds did) might have slightly different sized flanges.

Identify the drill size that allow the LEDs to pass entirely through.

Locate the center of the part. And drill it out. We are attempting to get the hole to come out centered on the short ridge.
  • When drilling, push slowly, otherwise you will 'pop' the wood out the other side.

Step 5: Reflector - Assembly

Picture of Reflector - Assembly

Tools:
Wood glue
strap clamp


Remove the LED's from the pieces.

Using wood glue, apply and smooth on the piece. Place in a strap clamp and let dry.

Step 6: Electronics

Picture of Electronics
Tools:
soldering iron

Supplies:
1 9-volt battery
1 9-volt battery pigtail (used in step 9)
3 red LEDs
3 yellow LEDs
2 resistors
~6 feet of wire.

Depending on the specific LED's used, you may need different resistors that listed in this instructable

We are using a 9-volt battery as our source. And are using 3 LEDs for each light.

The YELLOW led's I used had a voltage drop of 2.0 V, current draw of 20 mA. Using LED series/parallel array wizard I needed a 150 Ohm resistor. For the RED led's they have a voltage drop of 1.7 V, so the resistor needed was 220 Ohms.

Refer to the LED series/parallel array wizard for wiring.

Wire assembly:
You will need 4 wires for each light. Into one hole place two wires. Run one wire clockwise to the next hole, and the other counter-clockwise to the next hole. From the two holes, place one wire in each. The two loose ends will be attached to the battery.

For each of the reflectors, you need two wires that are long enough to reach around the perimeter of the reflector (shown in the image as the red and blue wires), around 9 inches.

You will also need two wires (illustrated by the green and cyan) that will need to be around 2 feet. The wire lengths need to be long enough to extend from where the reflector is mounted, to where the battery is mounted. Extra length is fine, you can always shorten the wires.

  • Take each of the LED's, and cut the leads shorter. Remember to keep track of which lead is longer. When I cut them, they were cut so that the longer lead was still longer after trimming.
  • As illustrated in the diagram, wire the long lead to the short of the next LED. This is very, Very important. If an LED is wired in backward, none of the 3 will light.
  • After soldering, put a small piece of electrical tape around the bare wires. It will all a little strength and keep the wires from shorting as easily.
  • Take the green and cyan wires extra length and twist them together. Later you will want to wrap this in electrical tape once you know the length needed.

Step 7: Light Assembly

Picture of Light Assembly
Tools:
Hot glue gun

Make sure to test the circuit works before gluing the LEDs in.

  • Grab your hot glue gun and glue those into the holes.
  • You will have extra wire once everything is glued in. I pull taught the wires, folded the along the outer corner and taped them down so as to not get caught in anything.

Step 8: Apply Reflective Material

Picture of Apply Reflective Material

Supplies:
Aluminum foil

Tools:
wood glue


I used aluminum foil as a light reflective surface. I cut strips out of an ordinary roll of foil. Dry fit them and trim. Use wood glue and apply it to the surface. Smooth the glue with your finger, and apply the foil.

Step 9: Battery and Cabling

Picture of Battery and Cabling
Supplies:
2 film canisters

Tools:
Utility knife
Hot glue gun
Electrical tape
soldering iron

For the battery case, I used two 35mm film canisters. A hot glue gun, a 9-volt battery clip, and electrical tape.

In order to have enough space, a single film canister does not work well. The solution here was to cut the bottom off one of the canisters and hot glue two of them together. This solution does not have a switch, you have to simply unplug the battery to turn off the lights. No switch was included due to the possibility of the unit getting wet.

Battery case assembly
  • Cut off the bottom of one of the canisters.
  • Tape the two canisters together (on the inside )with a piece of electrical tape. Leave a small gap between the two canisters. This will allow the hot glue to more securely attached the canisters.
  • Warn up your hot glue gun. ** Hot glue is HOT.
  • Apply liberal amounts of hot glue to the joint. Smooth the hot glue. I used my finger, with some padding so I did not burn myself. See the next point for what I did.

---* How to safely smooth hot glue with your finger:
. Take a small piece of cotton, like a portion of a cotton ball, a folder piece of scrap fabric,etc. Possibly a band-aid may work as well. You don't want this to be too bulky, but enough to keep from burning yourself.
. Use some electrical tape to tape this insulation to the end of your spreading finger.

Electrical connections
  • Put a small hole in the cap, the four wires will go in through it and connect to the batter pigtails.
  • Make sure to use some electrical tape so wires don't touch inside the tube. Solder the connections.
  • coil the four wires (two of which have resistors connected) along the lid and glue in place with some hot glue.

Step 10: Finishing

To turn the unit on/off simply remove the cap and plug/unplug the battery. When not in use, the unplugged battery can be placed in the tube backward.

There is no switch because I wanted a water sealed unit.



I ended up drilling a couple holes in each piece to help provide a point of attachment. I have not done so yet, but I would highly recommend painting or otherwise sealing the wood.

[Optional]
I found that placing a piece of wax paper or rice paper over the triangular section provides a nice diffuser for the light. However, they don't really have a long life outside.

Comments

jeff-o (author)2008-11-24

Oh, I see - there's no need to seal everything, just the LEDs. Nice.

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