Step 1: The Materials and Tools
- 18 red LEDs 2.6 volts
- 2 green LEDs 2.1 volts
- 6 resisters 1/4 watts, 220 Ohms
- A plastic box approximately 4.5x9x1 inches
- Aluminum foil
- One 9 volt battery
- 1 battery holder
- 2 flip switches
- 1 switch
- Duct tape
- Electric tape
- Multi-purpose ties
- Soldering iron
- Wire stripper
- Exacto knife
- Super glue
Step 2: Building the Base
O.K., let's get started.Take a piece of cardboard and draw a triangle so that it fits in the box and so that both triangles still have about 3 inches in between them. Measure about a 1/2 inch away from the triangle. Then cut the cardboard with an exacto knife and trace it to make a second piece. Cut very shallow on the line where the triangle is to bend the cardboard pieces so that they can "stand up". (Look on the picture because it might be confusing.) Then put the triangles in the box and adjust it if it doesn't fit.
Now, once you're done with that, glue aluminum foil to the triangles (not the parts that bend!) and let it sit overnight. I added aluminum foil so that it acts as a reflector for the LEDs. Make sure that you leave plenty of room around the triangles so that when you're done, bend the aluminum foil to make a border around the triangle.
Poke 9 holes in each triangle so that they aren't too close to the ends.
I did it a bit differently, but this way's probably easier.
Step 3: Attaching the LEDs
Put the red LEDs in each of the holes on the triangles. Divide them into three groups (for each triangle). Each group contains 3 LEDs connected in series. Attach 1 resistor to each group. Test it with a battery to check if your connections are correct. Then test it with the three groups in parallel. Look at the picture for details.
When you are done testing, solder the LEDs and resistors in series and then solder all of the pieces together. (Use wire in between the LED and resistor because you need it longer.)
Put the triangles in the box and tape them with electrical tape. Make sure that you don't short the circuit.
Step 4: Attaching the Flip-switches
Tape a green LED to the side of the flip switch with electrical tape. Then solder it to the switch. I did this because you know when which arrow is on or off. The green LED shines with the red ones.
Attach the LED to the switch as it shows on the picture. Then tape it to the handlebars. You can put it wherever you want, but its easiest to have it at the end.
Step 5: Putting It on the Bike
When you attach the wires to the switches, measure out about how far it is from where the switch is to behind the seat. Use multi-purpose ties to stick the wires to the bike.
Cut a hole in the side of the box for the main switch to go in and connect all of the wires as shown on the schematic diagram. Then just attach the box to the back of your bike. I can't exactly tell you where because everyone has a different bike but if you have a basket, put it on the basket; if you have a bag, put it on the bag; and if you don't have either, you can either duct tape it underneath the seat or make a wire holder.