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How-Tuesday: DIY Bike Light

Jun 19, 2012

by ElectricApparatus handmade and vintage goods

Bike under the silvery rays of the summer moon with this do-it-yourself bicycle light tutorial by Chicago-based Etsy seller Robert Katovich of Electric Apparatus. Safety first!

They say necessity is the mother of invention. Well, DIY is often the child of negligent parents. I don’t mean that in a denigrating fashion, but if you’re not breaking things, you’re not doing it right.

So many objects are made to break and be thrown away, but many are easily fixed if one takes the time to examine their faults. DIY not only functions as a way to easily fix broken products, but also as a way to build your own sturdy designs.  I have had so many bike lights break, get stolen off my bike, or just fall off while riding (or getting hit by SUVs) that I created LED bike lights made from recycled jars. I have never had one of my handmade lights stolen or fall off.

Recently, I found myself on the West Coast borrowing a bike from a friend, which had no light. The nearest bike shop was five miles away, so I came up with this design for an easy-to-build bike light, using parts from the local hardware store, an LED from an electronics chain, and a small plastic spice jar.


– 1 small jar with a plastic lid*
– 1 ultra bright white LED
– 2 small eye bolts
– 4 nuts that fit the eye bolt shaft.
– 2 small nylon washers
– 1 3V CR2032 battery (available at local drugstores, or online for way cheaper)
– 2 hose clamps – 1 size SAE #12 for attaching the light to the handlebars, the other sized for the jar being used
– 1 rubber band

– Drill
– Pliers

*If you don’t hoard empty jars for future crafting endeavors, you can always empty one into a bag and label the bag with the spice name. A jar full of fennel will never save your life, whereas this bike light might. The important thing is that the jar must have a plastic lid for this design to work, as the eye bolts need to be electrically insulated. For a bike light design with a metal lid jar (like jelly, honey or baby food jars) , check out my DIY baby food jar bike light kit in my Etsy shop.

1. Empty and clean the jar of any spice debris. I opted not to wash the inside of the jar, so that it retains the pumpkin pie spice smell. (I know many of y’all sniff bike lights, don’t be ashamed.)

2. Drill the holes for the eye bolts. I used 3/16″ by 1-1/2″ long, zinc plated steel eye bolts, the smallest available at my nearest hardware shop. Avoid stainless steel, due to its poor electrical conductivity. The holes need to be wide enough for the eye-bolts to fit through, and just far enough apart to fasten and tighten the nuts. I find 1/2″ apart to work perfectly. Also, off-center the holes slightly to the top, so that the LED will be centered in the jar.

Insert one eye-bolt into each hole, line up the “eye” sides.

Insert the nylon washers onto the bolt shafts, and fasten to the lid with one nut each. Tighten with pliers.

3. Prepare the LED by orienting the longer lead (+) to the right, and slightly spreading the leads into a V.

Curl the tips of the leads to the right with a nail or pencil.

Hook each curled lead around the corresponding eye bolt shaft, marking the bolt that is attached to the longer lead (+).

Attach the remaining nuts and tighten to hold the LED in place. Make sure each LED lead only touches one eye bolt shaft (this is important).

Bend the LED so it faces away from the jar lid and rests on the eye bolt shafts.

4. Stretch and loop the rubber band around the base of the “eye” part with enough loops to pull the eyes together until they are about 1/16″ apart.

5. Insert the battery between the two “eyes.” Orient the battery so the flat (+) side touches the marked eye bolt attached to the longer LED lead. The tension should hold the battery firmly in place, and the LED should light! Once the LED lights, you can insert the battery backwards and the LED should remain off. This is the switch.

When you need the light on, insert the battery so the LED lights. When you don’t need the light, reverse the battery. An LED is a diode, which has the main purpose of only allowing current in one direction. So with the battery reversed, the LED will not drain the battery and essentially act as an off switch.

6. Insert the smaller hose clamp into the larger one.

Tighten with pliers or a flat head screwdriver around the jar body. Open the smaller clamp, and attach and tighten to your handlebars. Once attached, you can leave the battery in backwards until you need to use the light. If you feel uncomfortable leaving the light on your bike, simply use a small coin to unscrew the top hose clamp slightly, and remove the jar, leaving the clamps in the bicycle. Replace the jar and tighten when  you are ready to ride again.

7. Ride safe!

If you make your own bike light, share a photo with us in the Etsy Labs Flickr group.

More Things to Make | DIY Bike Tube Pouch | Bike Accessories on Etsy


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