A reader submission from Mike of NC:

It’s that time of year again…time to bust out the headlight for a midweek-after-work-night ride! But, in order to have a fun and safe nighttime mountain bike adventure you need one critical piece of equipment…a bright light to adorn your helmet and illuminate the trail ahead. The only dilemma is, a good light system can run between $200-$300 bucks. I don’t know about the rest of you, but that’s a little rich for my blood. That’s why last year I decided to take the MacGyver approach and build my own. I started out doing some research on the web and found a lot of good information. Then I compiled a list of parts and began the process of building a reliable helmet light with a decent amount of runtime.

Here is a list of the item’s you will need in order to build your light:

1. A 12-volt, 20W halogen MR-16 bulb. These are made in a variety of wattages and reflector angles. I chose a 20W narrow spotlight with a reflector angle of 12 degrees. Also, make sure you buy a bulb with a glass lens. Some of the bulbs sold do not have a lens over the reflector at all. You should be able to purchase the bulb at any home improvement store for around $6.

2. You will also need about 3-4 feet of 12V wire.
3. Misc. electrical connectors.
4. (2) male and (2) female RC connectors. These are used to make quick connections. They are manufactured for remote control cars and can be purchased at any Radio Shack or most hobby stores.

5. A switch…I used a simple in-line switch.

6. A battery…I used a 12V 4.0 amh sealed lead acid battery. You can purchase this exact battery HERE. You will also need a charger and a charger chord. The battery, charger, and charger chord can be purchased at www.batterymart.com best of all their warehouse is located in Virginia so that means it want take long to receive your stuff.

7. You will also need some sort of housing to hold your bulb. I know this is kind of a rigged approach but trust me it will work. I pulled the plastic top off a can of air wick air freshener and removed to trigger portion and it is a perfect fit for the 2” halogen bulb. The cap is also tapered along one side, which should match up very well with the slope of your bike helmet.

8. 2” wide Velcro strips…use these for mounting the light to the helmet.

Now it’s time for assembly!

Get your high tech housing and insert the bulb into it. It should fit a little loose. Run a bead of hot glue or silicone sealant around the perimeter of the glass lens to hold it in the housing. I also ran a zip tie around the housing just to be sure it was a tight fit.

Use some simple electrical connectors to attach the wire to the leads on the backside of the bulb.

Use enough length of wire to reach the base of your helmet. Then attach a male RC connector. Somewhere along the length of wire I installed the switch so that it is located at the top of my helmet and easy to reach.

Now, make a patch chord to go from the battery to the base of your helmet. Place a male connector on one end and a female connector on the other end. Next, attach simple female connectors to the remaining female RC connector and slide them onto the battery terminals. Make sure that the battery connection is nice and tight. Below is a schematic of what you should have when finished.

All that is left to do is place some adhesive Velcro on your helmet and the bottom of the light housing (tapered side). Also, place Velcro to the top of the housing and use a strip of Velcro over the top of the light and attach to the helmet. Take a look at the pic below to see exactly what I am trying to explain.

To use this highly sophisticated design simply attach the light to you helmet and place the battery in your hydration pack (or a small backpack) and you are ready to mount a nighttime assault on the trail of your choosing!

What you will have when you are finished is a bright and reliable helmet light for around $50 bucks. I used mine all last fall and winter without any problems and I am planning on using the same system this year as well. A full charge should burn the 20-watt bulb for 1:45 minutes until it begins to fade. All light should diminish at the 2-hour mark. If, you decide to build one for yourself your need to time a full discharge before you go out on the trail to be sure of the amount of time you can get from a single charge. The batteries are only $12.95 so you could get 2 and rotate them out for about 3.5 hours of burn time. Enjoy some extended ride time this fall and winter.

Click Here to download a ZIP file with larger pictures and schematics.