Bike Light and Turn Signals




Step-by-step instructions on how to build a rear mounted bike light with turn signals for day and night use, so drivers can see you and where you are going. All comments are accepted, I would like to hear ways i could improve this.

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Step 1: Materials and Tools

-6 leds-color is a personal preference-Red/amber main light, yellow for turn signals

Don't use blue lights like i did, after making it i was informed blue is reserved for police

-2 mini-toggle switches
-1 Slide switch
-9v Battery
-9v snap connecter
-1 Project box-any size bigger than 4"x 2"-aluminum cover is needed
-1 Bic pen or Mechanical Pencil

-Soldering Iron
-Various Screwdrivers
-Wire Cutter/Stripper
-Hot glue gun

-Breadboard Wires

Step 2: Optional: Prototype on Breadboard

Try Before building-use a breadboard. If you are not using a breadboard you may skip this step.

Step 3: Drill Holes for Aluminum Plate

Mark where the holes will need to be, on top of the box, having the plate facing away from the cover. Drill or ream holes so that the plate fits flush to the box. Screw the plate in-place with the thread of the screw is on the out side of the box.

Step 4: Mark and Drill Holes for Leds

Take the four leds and make them in any shape, i made mine in a square. mark and drill the holes. also cut holes where the wires will run for the turning lights. Cut the Bic pen barrel in half, theses will be mounted on the sides and used to hold the turning lights. Also cut a hole large enough for the slide switch.

Step 5: Solder Everything Together

Solder the components as shown in the schematic. Sorry for lack of pictures, i wasn't allowed to use the camera when i was soldering.

Before soldering the turning leds to the main components, solder on the main leads, and run the wires through the Bic pen you cut in half. Also before soldering the switches that will be mounted on the handle bars, drill a large hole in the top of the box.

Use only one negative wire for the 2 switches, to the handle bars, for the turn signals-at the end split it to two. Then from the 2 switches run two other wires bake to the leds. Also remember to cut the wires running to the handle bars longs enough that they will not limit your turning ability.

Step 6: Hot Glue Everything Into Place

Start by hot gluing the turn lights into the pen, so that they will be water tight. After that dries glue the pen halve over the holes you cut for the wires to run to the inside of the box. Now glue the four leds into their holes. After the Leds are in place and the glue has dried, carefully glue the slide switch into place making sure that the switch has enough room to turn on and off. Once everything is glued on screw the cover in place.

Step 7: Now Solder the Toggle Switches

After everything is hot glued in place take the wires for the turn lights and solder the switches in place. Also to prep the switches to be placed on the handle bars, take 4 mini zip-ties and loop one under the little tab used to keep the switch straight. in this zip-tie place a second one which will hold the switch to the handle bars. Do this to both of the switches. You can see how this is done in the second picture.

Step 8: Attaching the Lights to the Bike

Thread a mini zip-tie in each holes in the aluminum plate. Now tie the ties to the under side of the seat. After the zip-ties are firmly attached to the under side of the seat take a large zip-tie and wrap it around both posts of the bike seat and attach firmly. Now attach the two toggle switches to the handle bars in a spot where they are comfortable, for me it is one on each side near the grips. Attach the 3 main wires running from the switches to the part of the frame that holds the fork in place. Now Attach the 3 wires to the seat post and then up to the front part of the under side of the seat depending on the amount of slack you have in the wires.

Step 9: Using the Lights

To use the lights you turn on the rear main lights, and when making a turn, like a car, you flick the signal switch in the way you are turning. For stopping you can also turn on both lights.

Step 10: Now Go Out, Be Safe and Have Fun

Have fun riding your bike which now sports a new light and turning signals.

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    63 Discussions


    2 years ago

    I am looking for signal lights for my bike that have stand-offs similar to those on a motorcycle.If you have signals on your bike here they have to be at least 600mm apart on both front and rear.Any help would be appreciated


    10 years ago on Introduction

    I recently purchased directional turn signals for my bike and the 1st day I used them they saved my life at an intersection where a truck was making a right turn. It's a no brainer. I purchased mine at I can't understand why I don't see more bikes with safety directional signals. Do you.

    2 replies

    Reply 9 years ago on Introduction

    i signal with my hands, but i agree that signal lights would be helpful, especially at night.


    Reply 9 years ago on Step 1

    Oh ya this is easy,
    im making one that uses transistors to make the lights flash


    Reply 9 years ago on Step 1

    How would that work? I'm trying to learn all I can. I have a soldering iron, I can buy some leds, transistors ect.


    Reply 9 years ago on Step 1

    Heres the link to the schematic:

    You need to be pretty good at reading schematics, soldering transistors and picking out all the parts. Im in HS and I taught myself to read these things so if you dont understand something, feel free to reply!


    Reply 9 years ago on Step 1

    "if you don't understand something..."

    Lol, I don't understand any of it. I'm off to learn how to read schematics.


    Reply 9 years ago on Step 1

    O ok, ya its easy to teach yourself about schematics, I did, just use wikipedia.

    You should actually order a kit off of a site called The Electric Goldmine, the kits run cheap (<5 or 10$) and come with schematics, along with detailed instructions in case you can't quite read schematics yet. You just need to have a good soldering gun and solder.


    10 years ago on Step 10

    Hot glue and moisture won't work well together. I think the young man is doing fine but reading a bit about materials might help a bit. Bikes get soaking wet. Therefore just about anything for a bicycle needs to be really water proof.

    1 reply

    Reply 9 years ago on Step 10

     I made a bike light using hot glue and ride in snow and slush in Montana. I splash through puddles and mud. Light works fine even with exposed switches. Waterproof is for things that get submerged in water.

    If you buy a bike light that claims to be waterproof, drop it in a body of water and watch it stop working fast. Most lights are only water resistant or splash proof. 


    9 years ago on Introduction

    this could be very useful for my mum when she's cycling (just because my mum is quite dangerous when cycling) thanks ! :)


    10 years ago on Introduction

    By chance how many LEDs did you use for the main back light? and do you remember what the mcd rating was for them? Not too sure about that myself. Thanks


    10 years ago on Step 9

    If you get 'blinker' leds you don't have to keep flicking the switch for your turn signals.


    10 years ago on Introduction

    Forgot to say: I'm building one of these for my electric bike. That is once I get around to building it. Again, Great job!


    10 years ago on Introduction

    I'm very impressed. You have a very good form factor, not something most 13-year-olds would think about in the design. The reason for a resistor in series with the LED's is that it "burns off" the excess voltage that *could* damage the LED's. I don't think you'll ever get a voltage spike from a battery that would cause that to happen in the setup you have. But if you wanted to set up a dynamo to power the lights (along with a capacitor in parallel to level out any ripple volts and act as a "battery bank" (just pick one with a voltage above what the dynamo can produce and include a zener diode with a resistor in series with it to regulate the volts)) then the resistors would be necessary. The LED-series resistor doesn't have to be of high resistance; just make sure the watt rating is a quarter watt or over. Good job!


    10 years ago on Introduction

    I think that this is a marvellous instructable you have added here. I have been pondering how on earth to mount the indicator LED's, and you've solved it! The only comment I would like to make is to consider making the indicator LED's yellow, as is convention with other road vehicles. Jolly great work mate!


    10 years ago on Introduction

    Pretty good, but here are some suggestions for Version 2: - Use AA batteries instead of 9V, you will get a much longer run time. - Add a resistor for each series chain of LEDs, or they will burn out - especially the turn signals! - seal the enclosure with silicone or hot glue. If you get stuck in the rain, water WILL get in and destroy everything inside. - as others have suggested, use red LEDs in the rear, not white or blue.