I am planning to construct a halogen headlamp for night rides and winter commuting. The design is from here:

https://www.ladyada.net/make/bikelite/index.html

Anyone else used this protocol or any other? Please enlighten me with any information/experiences that you may have. Thank you guys and gals.

I'm very tempted to give it a try, though it's over my head. I think it would be cool to build a second light with a red filter to illuminate the road behind you, like the DiNotte taillight does - to create that visible "buffer zone".

You'll probably have better response in Electronics, Lighting, & Gadgets, but I'm glad you brought up the idea here or I never would have seen it. I'm going to poke around that forum now myself.

Jon: If you decided to work on this, please keep me informed on your progress and where and how you got parts etc. I will do the same. The things that I am concerned about is cutting the PCB circular. May be I will email the author and get more info.

Gotta get this going before it starts getting dark sooner.

As I see it, unless you're an electronics sort-of-guy, this is making something very simple, well, very difficult. I built the Home Depot Halogen headlight in 2 nights. Dirt cheap. Reliable. With a 4.5 AH SLA and a 20 watt halogen, I get 2 hours of good light. then it drops off pretty quickly. If I were only riding road, I would put a 7 AH battery on a rear rack.
I used https://bike-recumbent.com/headlight.shtml
...thehick

My lights are close to these:

https://www.bikeclub.org/lightspa.htm

I used 4" of 3/4" copper tubing and just glued the bulb in. I soldered wires to the MR16 bulb and ran them out a drilled hole to a switch and then to a 14.8v Li-Ion battery. I used a 12v 20W halogen bulb. Very easy. I know I am over-volting the bulb but after a year it is still going strong. It puts out a tremendous amount of light. My battery is 4.8AH from batteryspace.com. I get more than two hours from it.
Every few months I get energetic and upgrade some things. I have added a softstart circuit to make it easier on the battery pack when the light turns on. (This would not be needed for NiMH or Lead Acid.) I have recently put in down converters and am running my blinking headlight and taillights from the same battery pack. I am not sure that I have saved any money but I have enjoyed the project.

I don't think I'd bother with the circuitry. Just hook it straight up. The extra couple volts won't bother the lamp that much. You'll still get a year or two out of the halogen.
I have a similar switching regulator on my HID, but that's because my HID's ballast WILL fry if I overvolt it.

I don't like the design of that regulator much. It really should have a series inductor of 100 uH or so and a capacitor across the output of perhaps 470 mf or better. As it is it's going to have an extremely rough and spiky output and will probably generate RFI like crazy; you won't like it if you have a wireless computer or you listen to radio.

Does seem complicated - you are not going to actually want to dim down from 10W...

In my experience you need 15w halogen, or more, to see at speed.

Try this link for an excellent DIY LED light. I made one of these 2 months ago and it is terrific. You can mount it on your bike but I like it mounted on my helmet. With the rechargeable battery it lasts 8+ hours.

https://myfwyc.org/bikeled/DIY_LED_Bi...ing_Guide.html

I am in the middle of a DIY project myself. Chapman's design is pretty nice (I like his mounting method). I also liked this design: https://www.mouldy.org/projects/High-Power-LED-MTB-Light

However, I wanted something where I had a fair amount of control over the (for the lack of a better term) UI of the light. I have a pretty nice prototype running on a breadboard right now, and am finalizing some details on the board now. I want to try to carve out a little room for some on-PCB strain relief and an ISP header yet still fit it under batchpcb's 1 sq in billing minimum.

For any light designers reading this, here are some features I wanted that made me go my own way:
- Latest-generation LEDs.
- No direct drive. It's 2007.
- Flash patterns that don't vary the light level from 100% to 0%, but instead go from 100% to, say, 75% - this reduces annoyance for cars and makes the light easier to see by.
- Memory of last-used mode (flash vs. steady) and flash pattern / light level.
- Easy access to flashing mode or straight-up mode without having to cycle through a bajillion modes, a pet peeve of mine. This pretty much means the light needs more than one button.
- Wide coverage. Ideally, plenty of light thrown to the side, but I see that can be kind of tough with modern optics.
- Capable of brightness levels that are adequate for unlit streets/trails. That way you don't have to buy two lights.

I chose the Buckpuck 3021 for the current source, but I also looked at the bFlex (decided against it because of its flashlight-optimized form factor and because I wanted to control the UI) and rolling my own current source (reasonably easy with the chips out there, and full control over things like ripple, but still a lot less simple to integrate). The Buckpuck is freaking huge by my standards but it works really well.

The light is run by an AVR. They are pretty capable, are super easy to integrate, and you can program them in C with a free toolchain.

I'll post some details when the project is done. The days are getting shorter here in the Pacific Northwest, so I'd better hurry up huh?

I'm currently building one of those right now, with a few modifications. I used the Fatman from Taskled instead of B-flex, that way I only have to carry 7.2V 2650mAH of AA Ni-MH battery (which I already have) instead of the Li-ion 14.4V. Although the runtime will be short at full power (1A), I don't plan to run it at full power as it is an overkill.

It was my impression that you could use the b-flex at lower voltages as well. The manual says "Input operates from 4V to 25V".

B-Flex will not regulate when if the battery voltage is lower than the LED.

IE. 4V Battery with a single 3.4V LED, it will work considering that the battery voltage will not drop below LED voltage.

7.2V battery with three 3.4V LED (total 10.2V), BFlex will not regulate.

Got ya.

What about mounting Q5 LEDs in the MR-16 configuration [3 LED] into a 2" diameter piece of aluminum tubing? If I'm reading the handy graph correctly, that's ~100 lumen/LED x 3 = 300 lumen at 350 mA. So going to 700mA would give around 600 lumen, and 1000 mA would be ~800? I'm kinda making this up as I go, so please correct me...

I do a lot of riding at night and I've tried the 20-watt halogen DIY lights as well as other not so bright less weight options. I've finely got a system I like. I'm using a Mag-Lite 2 AA 3-watt flashlight as a headlight, cheap Schwinn Dynamo, 2 "C" size NiMH rechargeable batteries, 4 1n5818 diodes, and a 5000 MCD red LED as a tail light. I started out using an LM317 voltage regulator circuit but a student studying for an electrical degree gave me this circuit and short description.

I built a test setup for that circuit and so far I have 56 nighttime test miles on it.

Here is a photo of the terminal strips, dynamo, bridge rectifier, switch, and batteries.

Sorry it's so ugly but I want to thoroughly test it before spending money on nice stuff like project boxes and new solder tab batteries. Using the terminal strips allows connecting my voltmeter much easier as well as swapping out parts. So far the batteries are keeping a near full charge without needing to use an external battery charger. The lights stay on when I am stopped or standing as Europeans would say and I can push the bike up a very steep hill while still allowing operation of the lights. The dynamo starts recharging the batteries when you're speed is at 8 MPH and above. Below 8 MPH you're discharging the batteries but the discharge is decreased as you approach 8 MPH. The dynamo stops supplying higher current above 14 MPH so you can't damage the components when going downhill.
I can now go on a tour or ride all night and never be worried about recharging or purchasing batteries!

3 watt maglite is not bright. I have a 3 watt maglite for general use. It is not bright enough for riding at any decent speed. As for dynamos, I'll go for hub dynamo hooked up to 2 Seoul P4 (or any of the latest led). Plenty bright for all night riding without having to worry about battery.