Introduction: Commuting and Trail Riding Bicycle Helmet Lighting Solution...
I am an Alaskan, all weather, year round bicycle commuter. I ride approximately 29 miles per day, round trip. My commute consists of approximately 6 miles of semi lighted Bicycle/Sidewalk on a thoroughfare, 6 miles of sparsely lit Bike lane roadway riding, 10 miles of intermittently lighted paved bike trail riding, and 7 miles of unlit offroad trail riding. I ride a 2001 Specialized FSRXC mountain bike with Nokian Hakka aluminum/carbide studs in the winter, and the same bike with Specialized Armadillo Fast Track tires in the summer. In Alaska, my lighting demands are harsh with my riding temperatures fluctuating between -20 degrees Fahrenheit (my personal riding cuttoff threshold), and 85 degrees Fahrenheit. In the winter, my ride is 100% darkness, and in the summer it is the opposite. Rain, snow, sleet, humidity, and just plain freaking cold air are all elements that myself and my lighting system have to endure. For the past two years, I have utilized two Nightrider K2 commercial bike lights mounted to a custom fiberglass overshell on my helmet for my front lighting solution, a Pelican 1-Watt flashlight for my rear flasher. During my hour each way commutes, I determined additional capabilities and desires that I wanted for my lighting solution.
For me Helmet lighting over bike lighting was the only way to go. When I can look at cars with my light, they know I am there. I have had zero close calls during my winter commutes due, I think to this choice of Helmet mounted lighting.
The following Instructable helped me achieve these goals. I needed lighter weight than most commercial offerings, Brighter spotlight capability(to aid with wildlife encounters etc.), Rear and Side!!! flashers, and selectable front flasher/direct beam capability. I did not need 37 modes of flashing, solid steel or aluminum enclosures, or a name brand system. Oh yeah, I wanted to use some batteries I already possessed to save some $$$. May I present my answer to seeing and being seen in the Harsh Alaskan urban and wilderness expanse...
Step 1: Materials List
I purchase nearly all of my materials on line from three sites: http://www.dealextreme.com , http://www.luxeonstar.com , and http://www.ebay.com . All aluminum is 1/8" Thick to facilitate screw tapping and heat dissipation. I utilized Phillips Luxeons because I know their quality from my previous commercial lights. There may be brighter ones out there presently, but I am well pleased with my choices. For the LED Power supply, I chose the buckpuck constant current driver, because I could incorporate dimming, flashing, and efficiency for a reasonable price versus trying to weatherproof a homebrew power solution that was less efficient. I wanted maximum battery life while providing maximum power efficiency.
Lighting System Frame
3/4" x 36 x 1/8" Aluminum bar from Home depot ~ $8.00
6" x 6" x 1/8" Aluminum sheet from metal supply store ~ $2.00
1 2/PACK CLEAR TUBE TYPE REGISTRATION / PINK SLIP HOLDER $11.99
LED's, LED Constant Current Drivers, and Reflectors
1 BuckPuck 1000mA DC LED Driver (With Leads) $15.99
2 Luxeon K2-TFFC LED - White Lambertian, 200 lm @ 1000mA $9.00 ea
1 BuckPuck 700mA DC LED Driver (With Leads) $15.99
4 Luxeon K2 LED - White Lambertian, 100 lm @ 700mA $6.21 ea
2 Luxeon K2 LED - Red-Orange Lambertian, 100 lm @ 700mA $4.63 ea
2 sku 04512 Star Connection Board for CREE LED Emiters (5-Pack) $2.00ea
1 sku 12436 25mm Plastic Reflector for LED Flashlights and Lighting Devices (5-Pack) $4.80
1 sku 04586 F3 33mm Smooth Plastic Optical Reflector (10-Pack) $7.81
1 sku 04579 FUJIK Silicone Thermal Glue (50ml Grease-Like) $8.44
1 sku 05604 Clicky Switch for Flashlights (11.8mm 5-Pack) $1.80
1 Lot (10) Mini Toggle DPDT On-Off-On Switch 5A-125VAC $9.16
1 Lot (10) 555 Timers $4.00
Frigid North Electronics -- Anchorage, Alaska -- stuff for dimmer and 555 timer strobe
47uF 16V electrolytic capacitor $2.00
220uF 50V electrolytic capacitor $2.00
2 x 5 Kohm variable resistor $2.00ea
5Kohm 1/4 watt carbon resistor $2.00
270 ohm 1/4 watt carbon resistor (red purple brown) $0.50
Transistor from old mouse for dimmer circuit free
I also used some miscellaneous screws that I already had, #4's, #6's, and Nylon #6's
Step 2: Napkin Sketch and Circuit Diagrams
Notice my maker notebook. It was free with another purchase. This was my first project documented within. Sorry if it is not consistent with electrical standards, but it works and works well. It utilizes three switches. Two on the outside. One controls the front and one controls the rear. The front switch allows the two 200 Lumen LEDs to run all the time, the 2100 lumen LEDs can be switched between constant on with no rear strobe, or strobe with the rear and side strobes. The rear switch enables or disables the rear strobe. The third switch is internal and allows me to switch to summer configuration where strobe is on all the time and you can switch off the front 200 lumen headlights. The totality of the electronics are the 555 timer circuit for the strobe, the dimmer circuit for the rear and side strobe, two buckpucks, and three switches. All LEDs are hooked up in series.
Step 3: Build the Frame
Through much trial and error on different projects, I have learned: Do not bend aluminum at a 90 degree angle. All of my bends were completed by bending the aluminum around a wood dowel so that the bend radius was enlarged as not to weaken the structural integrity of the aluminum as much as a sharp bend.
An important design consideration in my lighting system was for wrecks. Commercial systems are designed to shear off your helmet in the event of a wreck so as to minimize helmet and/or skull damage. All of my aluminum was screwed together with no more than three #4 screws to facilitate breakage on impact, but not during normal use. Additionally, Nonstructural components, including LEDs were mounted using Nylon screws to eliminate short circuits due to inadequate mountings.
Another important design consideration for my system was heat dissipation. I needed approximately 1 square inch of Aluminum inch per watt based on my readings, but I did not want a heavy heatsink up there on my head. Believe me, I have been riding for two years with three commercial lights on my helmet. It overweights the helmet and really works your back and neck on long rides. My new frame is all one big heatsink that works amazingly well.
I constructed my frame to fit my bike helmet and bent the aluminum accordingly. You will notice that my headlight does not swivel or pivot. After years of commuting, all with lights, I discovered that once I had the light adjusted, I never touched it again unless it got misaligned by bumping it on something. Bump-no-more, this light stays true to its aim.
The specified aluminum bar is easy enough to bend with your bare hands, but stiff enough to hold its shape. I drilled holes in nonstructural ares to reduce weight.
Please ignore the dirty entry rug, somehow I overlooked aesthetics while excitedly photographing my project.
Step 4: Assemble Electronics
The hardest part of the electronics was knowing that they had to fit inside the clear tube ordered from Ebay.
The 200 Lumen LED's have a Vf of ~ 3.7v, The Buckpuck has an equivalent Vf of ~ 2v. Each of the 100 Lumen white and red LED's have a Vf of ~ 3.4v. The Front segment consists of the two 200 lumen LED's wired in series. The rear strobe segment consists of two 100 lumen white and 2 100 lumen Red LED's wired in series. The two front 100 Lumen white LED's are selectable between front and rear, extending the respective circuit by two additional LED's. The voltage required for each segment is as follows:
3.7+3.7+2.0 = 9.4v
with 100 lumen LED's
3.7+3.7+3.4+3.4+2.0 = 16.2v
3.4+3.4+3.4+3.4+2.0 = 15.6v
with 100 Lumen LED's
3.4+3.4+3.4+3.4+3.4+3.4+2.0 = 22.4v
Therefore, the battery pack needs to be greater than 22.4v. You will later see that I decided on two Macbook pro extra batteries that I keep on hand for traveling. The are Lithium Ion with good discharge capability 10.8v, measured at 14.1v, long life, 60 Wh or ~5555ma, and the best feature of all, a built in battery level indicator.
Each of the LEDs were ordered bare. I had to hand solder each to the star base I ordered from Dealxtreme. I put a little bit of nonconductive Thermal paste on the base of the LED which was connected to the cathode, just to make sure I didn't end up with a short.
Step 5: Build Battery Connectors
Arguably, the battery choice is the most important component. Interestingly enough, I knew my battery choice long before I had worked out the details of the lighting system. My wife has a Mac Book pro, and so do I. Between us we have two extra batteries for when we travel. These just sit in a drawer until a scheduled flight. Rather than waste such a valuable resource, I thought I would use these as my power source. As I commented in the prior step, they are Lithium Ion with good discharge capability 10.8v, measured at 14.1v, long life, 60 Wh or ~5555ma, and the best feature of all, a built in battery level indicator.
All of these pluses, and only a few negatives. They are larger than I probably need. Well since I ride with a 16+ pound backpack every day, an extra pound or two just doesn't affect me if the power supply goes in my backpack. They have sharp edges which is bad news for backpacks, or during a catastrophic impact. They also have a proprietary blade type battery connector that I could not permanently modify to incorporate into my system.
The pluses: I have a charger in my laptop at work and a laptop at home. I can ride consecutive days with no recharge in between. I can check the battery level at anytime!!!!! They are actually lighter combined than the NiCad battery system that came with my commercial lights, which I have been carrying for two years.
I ordered two Macbook Pro battery cables from a Mac service store called "The Mac Store" in Anchorage, Alaska. They cost an additional $10 apiece, but gave me a safe way to power my system.
I built the battery holder frame out of 1/2" aluminum channel form Home Depot, and two rectangles of ABS plastic purchased from a car stereo store many years ago. The ABS is easily cut with a compound saw, utility knife, dremel, or other creative tool. I bent the ABS using a cigarette lighter to heat it and then bent it around the base of the battery to form and "L" shaped bracket with a 1/16" lip past the furthest point of the "L".
The battery is connected to the lighting system through an approximately 30" umbilical made of 2 conductor 16 gauge speaker cable leftover from the prewire of my home.
Step 6: Assemble Final Project
The light system is held onto the helmet with two 3/4" square pieces of heavy duty Velcro under the canter frame support, and two 3/4" x 3/8" pieces of Velcro under each of the side strut/side LED locations. Two lightweight velcro straps affix it to the helmet by wrapping through the helmet vents.
Each of the LED stars was thermal pasted to the frame. The paste on its own is probably enough to hold it on, but they were screwed to endure the miles and miles of vibration they would see.
The umbilical was reinforced with zipties and hot glue at the battery holder and ziptied to the frame for strain relief.
The lens for the front LEDs is a piece of 1/8" acrylic cloverleaf shape traced from the front headlight, cut with a dremel, and shaped using my grinder. It is affixed to the front using a single thin zip tie and Clear RTV silicone gasket material. This is a light weight method and is still water tight.
I aimed the headlight approximately 20 feet in front of me at my standard riding position. My average speed on a bicycle is about 15-16 mph between trail and pavement. This throw distance allows me to pivot my head slightly up or down to compensate for increased viewing range or close examination depending on my speed and obstacles. I have found this to work well for me. The spot that these lenses throw is approximately 8 feet wide at 30 feet, and has a 20 foot very slightly lit circle of overflow light which gives good peripheral viewing. Photographing light for comparison is difficult, but it is very bright even in street-lit areas.
The side LED blinkers are set back slightly rear of center so as to be visible from any direction but directed at cars approaching from the rear intending to cut me off with a right hand turn. They have worked very well so far. Even in a bike lane, it is amazing. Cars used to give me a 12" birth, maybe. Now, they consistently steer around me by 3-4 feet giving me much more safety on ice/snow packed roads. The best addition to my system closely matched by the battery indicator.
Step 7: Go for a Freaking Ride Already
Eventually I will add a permanent helmet cam to the setup to document all the beauty and the occasional bad driver, but for now let me give you some quotes from people who have seen the light over the past two weeks of use.
Coworker, light not on, "What in the hell is that? I was walking by, but had to stop and see what it was...God help you."
Paved trail user, I approached from the rear and passed her, "Why is your light so much brighter than mine?" She had a commercial light and a $3000.00 Surly bike. My answer was, "It's homemade. See ya."
Paved trail user, I approached head on, "Your light is way too bright. It should be illegal on the trails."
Car pulled up along side to make a right turn around me, "Well, there's no way I could miss you."
Sister-in-law, "If you blind the cars, they can't see you." I countered with, "If I can flash the cars, they know I'm there, so if they hit me, i will take them for everything they own."
Last night, the air had warmed up above freezing, while the ground and snow were at the days earlier temperatures of the high teens. It began to rain/sleet lightly which caused a massive ice fog. My headlight beam was visible as a very eccentric cone of light that extended as far as the angle of incidence allowed. It looked like something out of Star Wars. Just as the thought raced through my head, a motorist pulled up beside me and yelled, "You keep control of your light saber, mister." Ah, vindication.
Let me just say, I couldn't be more pleased with the lighting system. Get out and ride...Any day, any time.