Well here's the schematic I used. Employs a 555 timer IC to pulse the LEDs

http://www.dwoloz.com/555leds.gif

It gives a 6V input but you can use any voltage as the input, just need to adjust your resistor values on the LEDs so they don't get too much current

Yup, that circuit will work just fine. If you only need to drive four LEDs, you can even skip the second LED bank (driven by the 2905), the 220 ohm resistor, AND the 3053 transistor. The 555 timer can drive up to 200mA, ten times what you'll need to run four LEDs.

Yes, good to point out
The transistors are really only necessary if you want to output more than what the 555 can handle (which I do :D)

Also if you wanted just a plain flasher and not alternating banks it could be simplified even further

I'm not sure if this has been posted before, but if you thought you were geeky with the lights check this japanese bike out:

http://static.flickr.com/119/307424512_37f78c2225.jpg

:roflmao: I love the bull horn

Paging NeezyDeezy (and others) ... halogen overvolt question
 

Paging NeezyDeezy (and others) ... halogen overvolt question:

ND, looking through this thread I just noticed you're running MR16 halogens (SoLux) directly off a 14.4V NiMH battery. Any problems doing this? While I'm asking, anyone else driven halogens directly off a 14.4V (or, for that matter, 14.8V Lithium) battery, successfully or unsuccessfully?

Sadly, my original 12V battery is starting to give up the ghost, so it's time for a new one. But turning lemons into lemonade, buying a new battery does give me an opportunity to step up and take advantage of overvolting. I don't see why not to go all the way to 14.4 as NeezyDeezy did. And since I'll need a new charger anyway (my current one is 12V max), nothing is off the table -- including 14.8V Lithium. I need to think about this over the weekend, but the options I'm considering (from batteryspace) are:

• 14.4V x 5Ah, $75 including charger. Would require me to stick to 20W bulbs, but a 20W Philips bulb driven at this voltage will put out the same amount of light as my current 35W SoLux driven at 12V.
• Lithium 14.8V x 4.8Ah, $100 including charger. Same bulb situation as above, but only $25 extra and the battery weighs 1/3 of what the NiMH does. That's about 3 cents per gram saved! I'd be very hesitant working with bare Li cells, but the product I'm looking at minimizes the safety issues because it comes prepackaged in a water bottle with protection circuitry built in, literally plug and play. Very tempting.
• Lithium 14.8V x 7.2Ah, $160 including charger. Big enough to comfortably run a 35W SoLux, which I do prefer because of the bulb color and the 17* beam pattern (Philips bulbs are either a bit too narrow or a bit too wide for my taste). And at 14+ volts it will be about double my current brightness, true car headlight territory. Could be overkill, but there have been some dark rainy nights where I wouldn't have minded even more light than I have now. How important is that to me? I guess that's the $160 question I need to ask myself.

I'm not sure which option to go with, partly because I'm trying to decide how much light I want, how important it is to me that I can run SoLux bulbs, and how much I'm willing to spend (after the initial shock that I have to spend any money at all). I need to answer those questions for myself before I can make this decision, but I'm still interested in anyone else's input on driving 12V halogens off 14.4-14.8V batteries in general, and on the options I'm considering specifically.

I've been overvolting MR-11 (only difference is in diameter of the reflector) lamps for years now without any issues. I use either 6V overvolted to 7.2 V or 12 V lamps overvolted to 14.4V. Either one gives out the same amount of light and it all depends on how many batteries I want to carry. I use 15W and 20W bulbs but I use up to 4 lamps at a time.

My preference is to use RC car batteries (3.3 ahr or 3.8 ahr). If you wire them in series, you get a 14.4V battery and if you wire them in parallel, you get the same run time for a 7.2V system vs a 14.4 V system. One of the reasons I run both is that in early spring I don't need the run time of the 14.4V system and so I can carry only one 6 cell pack (much lighter). It just allows for more flexibility. They aren't 5 ahr packs but I can get a bit over 2 hours on a 20W bulb which is enough for my needs. If you don't need the whole run time for the 5 ahr pack, these are a less expensive option. These guys have them for pretty cheap (as little as $19 per pack). They also have a smart charger that will charge up to 16V for $25.

Rather than carry the batteries in a water bottle, I have Rocket boxes that I got from REI that work wonderfully for my packs. That way, if I have to fix the batteries for some reason, I can take it apart rather than have to cut the bottle away and refoam them.

Here's some pictures

A 14.4 V pack, wired in series

http://i144.photobucket.com/albums/r...e/IMG_0193.jpg

The batteries comfortably nested in their boxes

http://i144.photobucket.com/albums/r...e/IMG_0106.jpg

The battery boxes taking up the water bottle cages I don't use in winter time anyway.

http://i144.photobucket.com/albums/r...e/IMG_0174.jpg

Hope this helps

cyccommute Which battery boxes are those. They look easy to open

RE: Lighted helmet project. The Fiber optic cable arrived from Hong Kong and it's a real dud. I hooked up one line and went outside. Running Laser Red or Purple has a distance of about 6-10' Will try to snap some pictures tonight.

They aren't really battery boxes but a Cage storage box I got from REI. They just happen to work very well for my batteries.

Hi Glowboy, thanks for the excellent question.

I am still running the same 35W SoLux (4100k color) with the batteryspace 14.4V nimh. It's only 5AH, but this gives me over one hour of run time, which is perfect for my commute. It's extremely bright. Also, I would highly recommend overvolting with halogens, the only supposed reason not to is decreased bulb life - but let me tell you I've been running the same bulb at least 5 days a week for 6 months+ with no signs of slowing. As far as your battery choice is concerned, it's up to you but my recommendation would be to stick with nimh because it's cheaper and the slight weight difference doesn't matter much if any to a commuter.

Here is another addition to the geekyness thread...

as posted in another thread:

I got creative and mounted the Fiamm freeway blaster 134db 12v horn on my commuter bike =)

it is powered by the same battery I use for the lights... I installed a momentary push-button to activate the horn. =)

PS, for those who have trouble making anything out of these images, the fiamm horn is the black thing that looks like a shell right above the front tire...

The huge light assembly above is my malibu 20 watt 12v headlight =)

Here are the low quality cell phone pics :

http://www.velocide.com/images_old/2...mage_00004.jpg

http://www.velocide.com/images_old/2...mage_00005.jpg

http://www.velocide.com/images_old/2...mage_00006.jpg

http://www.velocide.com/images_old/2...mage_00007.jpg

http://www.velocide.com/images_old/2...mage_00008.jpg

http://www.velocide.com/images_old/2...mage_00009.jpg


edit: This thing is LOUD. VERY LOUD !!!!!!!!

Great work on the horn, fordfasterr!
If you ride in the rain very much, you might want to think about putting some sort of a waterproof membrane over the horn switch--something like a piece of tube. I found water would make the switch contacts degrade and not let enough power through to power the horn correctly.

Ok, will do =)

You can also get waterproof switches, though they will be much more expensive than a piece of tubing!

Project is nearing completion

Everything is setup right now except for the tail light (xenon) but thats just a simple hookup.
My rotary tool work is pretty pathetic so the box didn't come out great but it works and thats all I really care about

http://www.dwoloz.com/IMG_0146.JPG
http://www.dwoloz.com/IMG_0148.JPG
http://www.dwoloz.com/IMG_0149.JPG
http://www.dwoloz.com/IMG_0153.JPG

Where is the flux capacitor? :p
Nice build. Keep an eye on those bulbs--mine started to fatigue and crack near the mounting/contacts. (time frame--about a year).

Flux capacitor is on order, 1.21 jiggawatts!!


Thanks for the tip, I will keep an eye on them. I made sure the glue the hell out of them. I still feel like they will inevitably break but at 5 bucks a pop I don't mind as much

anybody know?
 

does anybody know how to make an LED light setup? I know that resistors are involved because too high wattage will cause problems in the LEDs. the question I have is whether or not several leds need several resistors, or if one resistor will work for say 20 LEDs. I have an idea for making a bicycle light that will be csomething close to infinately variable using a switch that will allow you to turn on one more led at a time. Whether or not it will work is another thing thing entirely.

"does anybody know how to make an LED light setup?"

There is a lot of LED lighting info including how-tos at http://forums.mtbr.com/forumdisplay.php?f=124 . Some of the finished projects rival many commercial products. I'm actually collecting the parts for triple Cree XR-E projcet. Nothing like a little DIY to keep a guy feeling good!:D

Update on the helmet lighting. The Fiber Optic lace arrived from Hong Kong although very cool in theory does not throw enough ambient light to be visible more than 4' away. The tube length is 3'. Brightest where closest to the LEDS (where you need it the least).

2ManyBikes sent a runner's arm band with 4 LEDs and reflectant. Had it out in daytime traffic but couldn't tell it it made much difference. Will have to have someone take my picture at various distances for day and night.

Headlight or tail light?

In any case, yes, you can use one resistor for a few LEDs. It depends on the voltage. For 12V systems, you can use five LEDs and one resistor.

Hey all you DIY Commuters - I have a completely new unused light rig including 13.2V battery, dual optronics MR16 housings w/ bulbs (dual 20W, one being one of those power savers), and dual marine grade switches currently for sale. Listing in the For Sale forum, but thought I'd post here in anyone was interested in it. :)

Read my post about 3 down from the top.

Resistors are not the way to go, you need a current source.

I've listed the components, if you can wire a plug, you can put these together.

The lens and light output of my rig are similar to the 3W Dinotte, but with longer run times.

Well, you have to consider the efficiency of using a resistor, compared to using a current regulator. Most regulators operate in the 90%-95% efficiency range, which is possible to achieve if you choose the right LED/resistor/volatge combination. For instance, if you're running a 12V system at 20mA per LED, and each LED (5 in series) draws about 2.2V, then you'll only be dropping 1V across the resistor. That works out to about 92% efficiency. At about 5 cents for a resistor, that's a whole lot cheaper than 14 pounds ($25 USD!) for a current source! It's just as safe for the LEDs, more compact, and easier to build, too.