Bicycle Turn Signal and Headlight Hack

Bicycle Safety Upgrade

By Jackson Arcade

Assembly Time: 2 hours
Difficulty: Intermediate
Designer: Michael Yancy

This project requires basic electronics knowledge and good soldering skills. During assembly, I ran into a few "learning lessons" and was able to add a few enhancements that made it even more practical.

The project includes two aluminum cases that can be mounted on a bike. One case has two orange turn signal arrows for the back and the other has arrows and a headlight that mount on the handle bars. On the front box there are two switches, one for the turn signals and the other for the headlight. The system runs on a 9 volt battery. The mounting hardware must be provided by or made by the builder, due to differences in bikes.

The original instructions from designer Michael Yancy are included as Steps 1 to 5. My commentary follows each building step.

Bicycle Turn Signal and HeadlightBicycle Turn Signal and Headlight

Required components:

Part Description Mfr. Part No.
Case, Aluminum, 3.5" x 1.4" x 1.2" 1550A
LED, Uni-Color, Orange, T1-3/4 LE3330
LED, Red, DIF, Blink, 3Hz, T1-3/4 LFH3360
LED, White, T1-3/4, 7000MCD UT5HW3-4D-URC3-4861-R
Switch, PB, SPST, Off-On, Yellow R13-23B-05-BY
Switch, Tog, Mini, DPDT (STM203F1) T203T6B6A1QN
Battery Snap, 6 inches, 26AWG, 6 Prong BC6-R
Modular Network Cable, RJ11-6P4C, 7 Feet Long, Reverse, Grey CF1/4W200JRC

Step 1: Mounting Holes

Referring to the photo below, on the main body of each case, lay out the holes for the arrows. Choose which case will be the one on the front and lay out the holes for the white LEDs. Next, you will need to drill a hole in what will be the bottom of each case for the connecting wire. Next, lay out the holes for the switches.

Drill the LED holes and the connecting wire hole with a 5mm bit and drill holes for the switches.

Drill the LED holesDrill the LED Holes

My Drilling Lesson

I was all set to get started drilling the holes into my case, but it took a little longer than I expected. I used a 12V hand drill and found myself drilling and drilling and drilling. I would recommend you to find a drill press instead of a hand drill, especially if you are drilling into a metal case like I was. It will definitely save a lot of time.

Step 2: Arrow Construction

Take one orange LED and place it in the center corner of the arrow. For the next LED, verify the polarity of the first LED, and bend the leads to 90 degrees. Place it in a hole next to the center LED, making sure the polarity matches and the pins touch. Solder the pins together. Continue with the rest of the LEDs in the same way. For the center orange LED, solder the red blinking LED to the positive pin, referring to the photo below. Test the arrow. If all works, make three more arrows.

Arrow constructionArrow Construction

My LED Switch Out

I changed my design a bit for D6 and D18 (blinking red LEDs) and replaced two of the normal orange LEDs with two blinking red LEDs that I had lying around. I also used a white LED (headlight) as it gave me enough light intensity, but you could use more than one. Using high output LEDs instead of a standard output LEDs increases the intensity of light.

You can add a blinking effect to your kit by adding a 555 timer operated in astable mode. You can also add a red LED which will act as a tail light to your bike which, of course, would require drilling extra holes.

Two is better than one: always keep spare LEDs stocked in your workbench. They will always come in handy if some of your LEDs don't work.

Step 3: Headlight Construction

Using the same technique for making the arrows, wire up the headlight module.

Step 4: Mount the Arrows and Headlight in Case

Gently push the arrow modules in their proper position and using hot glue, secure and seal the modules in the case.

Step 5: Wire Up the Project

Using the schematic shown below, wire up the switches and modules. Test the circuit. If everything works, use liquid tape on all joints, and let it dry, before retesting everything. Close the case.

The schematicSchematic

Connecting to the Front and Rear

Using a modular network cable was a clever way to connect the two cases as it removed the use of normal hook-up wire which would otherwise make the design messy.

Cut both ends and strip about 2 inches of wire. You will see 4 wires on both ends of the cable but you just need 3 wires. Connect the first to the POSITIVE of right side indicator, the second to common GROUND and the third to the POSITIVE of left side indicator for front and rear cases.

Adding a Switch and Pushbutton

This had to be done very carefully as there wasn't much space left inside the case. The original kit didn't come with this functionality, but I thought it would be cool to add a buzzer and provide another switch for it.

When working with a metal case, you need to have good soldering skills and make sure that the connections of your entire project do not touch the case itself. If they do, you will ruin your kit due to a short circuit.

After all the connections are made, the final step would be connecting the circuit to a battery.

The kit is now ready to attach to your bike.

Red flashing LEDsMy Enhancement: Red Flashing LEDs

Front caseFront Case

Rear caseRear Case

Inside the rear caseInside the Rear Case

Jackson Arcade is pursuing a master's degree in Mechanical Engineering at Santa Clara University. His interests include travelling, camping, trekking, rock climbing, river rafting and bungee jumping.

The original project designer, Michael Yancy, was born and raised in Michigan and currently resides in Ludington, MI. As a freelance costume and prop maker for House Shijo, he specializes in integrating lighting into his creations. As a self-taught metal smith, Michael makes custom auto parts. His interests include papercrafts and studying Japanese Samurai weaponry.