This is a quick and easy one.
A front bike light for your helmet, it goes where you go and shines where you look! No more multiple handlebar mounts on different bikes, broken handlebar mounts, cumbersome external batteries, etc.
After breaking several cheap plastic mounts I'd had enough of bike mounted lights. Enough I say! Why can't mfg's make fiber reinforced mounts!
Having used headlamps extensively for camping and hiking I decided it was time for a helmet mounted light that I could point where I wanted, especially in driver's eyes to alert them of my presence.
Step 1: Acquire LED Flashlight
Update 11/05/2012. I now use LED flashlights that are rechargeable and much brighter that what I originally mentioned in this instructable (a 3 AAA LED light from Sams Club). Amazon is a great source for these types of lights and batteries. There are plenty of resources for LED flashlights of all sizes, prices and brightnesses. Google is your friend. Most of these lights use a Lithium Ion battery that is commonly called an 18650 battery. LED technology has also come a long way, Cree and SSC have LED's that are capable of upwards of 900 lumen. If you want to go smaller and lighter there's also a battery called a 123 size. They're half as long as the 18650 batteries and allow for smaller lights that are still amazingly bright.
Step 2: Materials List
2) Some sort of thick plastic bendable packaging material (~1mm thickness)
3) Snip pliers or wire cutters (for cutting zip ties)
4) Lighter (bic preferred)
5) Sharpie (never leave home without it!)
6) Four zip ties (may need more or less depending on size)
7) Four rubber o-rings sized for the flashlight barrel (again, may need more or less)
8) Led flashlight
9 ) Scissors (not pictured)
Step 3: Protecting Styrofoam Ribs in the Helmet
Zip ties are an amazing invention.
However, zip ties putting pressure on the Styrofoam underside of the helmet when tightened was a problem. It caused deformation of the Styrofoam even without being fully tightened.
See photo for detail.
Step 4: Distributing the Load
To solve the deformation problem I used a ~1mm thick piece of plastic (from the flash light packaging) cut and bent to fit over one of the Styrofoam rails of the helmet. This plastic spread the normally concentrated load from the zip tie over a larger area of the Styrofoam rail to where it would not deform.
Find some sort of plastic packaging that is fairly sturdy, here I show the use of a cookie container. Using the sharpie mark an oval appropriately sized to the area of the styrofoam you wish to protect. Then using some scissors, cut the oval out (see 2nd photo).
The third photo shows the load distributor in place. You will see how this works with the zip ties in a later step.
Step 5: Securely Mounting Metal to Plastic?
This may seem a bit daunting and it is, so I didn't even consider it. The flashlights I bought conveniently had some ridges machined into the body. Ridges which I realized would easily keep rubber o-rings in place. I actually used o-ring shaped garden hose washers but any local hardware store will have a large variety of sizes to fit whichever flashlight you decide upon.
Two fore and aft ensured a nice interface between the light and the plastic helmet skin. See photo for before/after.
Step 6: Begin Assembly
See the photo montage below. As every bicycle helmet is different you will need to play around a bit with placement of the light and zip ties. I used an offset position for two reasons.
1) I found it allowed me the best alignment of the light so the spot was shining where my eyes looked when they were straight ahead and relaxed.
2) I may add another light to the other side that has a strobe/blink feature for even greater visibility.
Please note in photo 3 the zip ties are not fully snugged up. I left them a little loose so that I could reposition the light and get the alignment of the beam spot just right before cinching up the zip ties.
To get the proper alignment, put the helmet on as you normally would, turn the light on, and then use a dark wall that is at least 15' away from you. Adjust the light so that it shines where your eyes normally look when relaxed and looking straight ahead.
Photo 4 shows the piece of plastic we're using to distribute the load across the styrofoam rail.
Step 7: Finalize Assembly
Once the alignment is set and the zip ties fully cinched, cut the zip ties flush on one side and leave about 1/2 an inch on the other. I cut them flush on the side of the helmet and left them 1/2 inch long above the center air vent.
I found that the zip ties, when encountering sharp bends eventually set into their final position and loosen up a bit. leaving the 1/2 inch of zip tie allows you to use a pair of pliers to grip onto them and tighten up if they loosen.
For safety's sake, use a lighter to melt the ends of the zip ties so they're not sharp and you don't cut yourself on them. Believe it or not industries that work with zip ties a lot actually have "Zip Tie Safety" classes. A sharp zip tie at eye level can do some serious damage.
Step 8: Wrapup and Future Ideas
See more photos below. This helmet light has worked AWESOME, I've been using it for over 6 months now. My only concerns are that it's a bit heavy due to 3 AAA's (at first I felt a bit bobbleheadish) and it is unfortunately a single mode flashlight (it doesn't have high/medium/low or strobe/flash).
I am considering switching to smaller/lighter LED flashlights that use a single rechargeable 18650 cell battery and also mounting two lights to the helmet. One to run for illumination and the other to run in strobe mode, both pointed forward.
Hope you enjoyed and be safe out there!