why go that complicated , 2 transistors , a resistor aand a capacitor is all you need

For those of you looking for turn signals, this might be the configuration you need. On a flat handlebar you could just rig them to mount in the handlebar ends so they would be visible from both front & rear. Of course they are big & probably heavy.
http://www.vehiclelight.com/3805.html

A microcontroller is actually even easier and more flexible. OK, a LITTLE more expensive, I'm paying $2 for Atmel Tiny12V processors. But they can do a HELL of a lot, really anything you can think of, and they can control 6 lights (or whatever) or more. For just blinking one LED it might be overkill, but as soon as you start doing anything more complicated, microcontrollers are the way to go.

True confesssions, I snuck out the kids' Radio Shack basic electronics kit (untouched from Christmas) MAWA HAW HAW HAW Yeah, I'm still thinking about the turn signals:

Stuff that failed:
*Yellow 12V beehives draw too much power (for my 18V drill battery) Housing is perfect tho!
* On a 6LED Vista light, unable bypass the rubber power button to an external switch. Radio Shack said it can't be done. (I'll bet a guru can figure that out!)
* On the Vista, unable to disable all of the other blinking modes to run JUST simple ON-blinking and OFF.

The simple LED flasher on a bread board, works great. If the only way to get an simple BIG turn signal is to run it off AA, I may sacrifice the Vistas battery housing.

how bright is bright enough?
i use a white LED headlight super spot made by planet bike that runs 30hrs on 4-AA bateries $35.00 it does double duty as a flashlight if I had 2 I swear I could see in a black hole! I recharge the Ni-mh bateries in my solar charger maybe once a month.
and all my commuting is at night.
but I will conceed that making your own system RULES!
now if we only could get cars to SEE our blinding lights.

Pitts,
Sounds like you're already set. If you're still wondering, it might be good to measure the width of the beam (beam pattern) and distance (throw). And then calculate the number of feet/second that you normally cycle. Then guess a comfort range. So if you need a 3 second reaction time. It'd be:

feet/second * 3 = the distance that light needs to shine for you to react.

Is it possible to use a Li-Ion laptop battery for driving a lighting system? I'm thinking about driving a 12v/20w mr16 with my laptop battery, which is a 14.4v 4.3Ah Li-Ion battery. Before I dig out the multimeter and some thin wires, was wondering if anyone has tried this with the smart batteries on modern laptops. How smart are these batteries in general? Does the onboard circuitry regulate voltage? Will it even supply power when the three 'comm' pins are not connected to the laptop? If it is possible (without serious risk of me becoming a 20 mph fireball... which i guess would provide some wide area illumination), it is certainly appealing, as it provides a very nice battery and i already have a smart charger for it! the battery is an 8-cell li-ion pack for a thinkpad.

Well, let's do some math...12V, 20W, means the resistance should be about 12^2/20 = 7.2 Ohms. You will be driving it at 14.4 V though, so your current should be 14.4/7.2 = 2 Amps. The power should now be 14.4^2/7.2 = 28.8 Watts. Lithium Ions don't like high rates of discharge, but 2 Amps should be fine for a 4.3Ah pack. On a full charge your run time could be as high as 2 hours, BTW. Sound like a pretty good setup. Let us know how it works. Don't worry about frying your battery pack, BTW. Those packs have a lot of safeguards in them to prevent damage from a full on short.

Nathan

Yeah... I was wondering how far those safeguards went (i.e. safeguards to prevent power when not connected to correct computer model would suck). I do not think the rate should be a problem... I am just hoping the discharge safeguards are on the battery rather than the computer... i can burn DVDs on battery while doing photoshop actions, so i don't think a few amps should be a problem.

I'd also really like to find a U.S. supplier of the 20W osram sylvania ir (high efficiency) mr16s too. if i can get the battery & charger at effectively no cost, i'm willing to splurge on a nice bulb... interested to see if the high efficiency bulbs respond as well to overvoltage as the standard ones... if so, should be able to get nearly 50w/12v worth of mr16 light for around 25w.

shouldn't the current be lower when the bulb is operating at a higher efficiency (voltage)???

if this chart (http://www.myra-simon.com/bike/lights.html#overvolting) is correct, the power req'd should be about 25w... which would result in 1.74A. So 2 hrs seems well within reach. I am a little concerned with overvolting 20% without any voltage regulation though... although i've read conflicting opinions on whether the soft starting will actually lengthen bulb life significantly. i guess we'll find out!

Well, this may be tame, but...

I had an old NiteRider system kicking around. The battery was shot, but everything else was fine.

I picked it apart the other day - two Mr16s, a 10w and a 20w.

Hmmm...

So, I bought a 9500Mah battery pack from battery space.

And I'm about to hook up a 35w narrow spot, a 20w narrow spot, and I have a 12w HID. The HID is just about enough, but why not go overkill?

The last half of my night ride is dark - and I mean dark, as in *no* lights I don't provide.

So we'll see!

Overkill is better than get'n killed! Sounds like you're on your way! Well how much is a replacement battery for the NiteRider?

anyone been able to source high efficiency 20w MR16s??? either the osram decostar IR (narrow flood) or the philips masterline es (spot)??? would rather use a source someone here has dealt with before if i have to order internationally.

bulbs.com

thanks! i guess that's what happens when i get too specific with a search (philips masterline es 20w mr16). now if i osram sylvania would just start shipping the narrow flood (24 degree) to the U.S. i'd know for sure which light i like better... may save $ by ordering both from the u.k. talked to william (lvr maker) about regulation... he said not to bother with a regulator on a 14.4v system with 12v mr16s... said if i was using a 19.2v pack (which he recommends for what i'm doing) he'd say use a voltage regulator. alot of help that guy. thanks again.

OK, I did my first hook up.

Old RideRider system, new battery.

I soldered everything, and used heat shrink tubing on top of that.

At the end of the day, I had the HID light, plus 20w on high and 12w on low,

~32w, on top of the HID.

AWESOME!

Sloth, Very cool!
Ditto, I"m hooked up on the 18V 30W and rode in yesterday with it. That extra weight of the rack, battery bag, and battery is noticable. But doable.

The LED on the breadboard was no where near bright enough for a turn signal...The beehive spreads out the light...not sure how far back they can be seen. More LED's Watson! More LEDs!

vrkelley, these are the LEDs I am using now for "running lights" and will be turn signals after I get the wiring done this weekend (I hope!).

The first image shows the LED module and my LED beehive.
http://monarch.gsu.edu/jeff/bike/tur...DSCF000201.jpg

The white pipe is 1" id plastic.
http://monarch.gsu.edu/jeff/bike/tur...DSCF000504.jpg

This is the LED sign module I bought from BG Micro. They had a plastic hood I cut off.

http://monarch.gsu.edu/jeff/bike/tur...s/DSCF0005.jpg

I just discovered they get warm--I don't think that will be a problem if I just use them as turn signals. I have trying to figure out a way to use them as running/tail lights and as turn signals, just don't know if I can do it without re-wiring the entire bike! The wiring has gotten so complicated I had to draw a wiring diagram to keep things straight. Anyway, hope this helps. BTW, these LED modules are rated 12 - 15 volts and draw 90mAh.

i just came across this thing..
instead of using a landscaping light housing,
$33 for a real head for a bike light that mounts to your helmet..
http://www.trailheadlights.com/details.html

Ya, I saw that too, and it looks pretty nice. Try to purchase one, though, and you'll find out the rest of the story...he's not making them any more.

Wow awesome lights. 90mAh is getting up there in power but probably worth it!
I got side tracked on a couple of other projects for a few more days.

Well, I *finally* got the wiring on the turn signals straighten out. I couldn't make the flasher work using one common indicator light, so I just added a two small clearance lights to both sides the front bar/turn lights and it works just fine. I am using the lights now and will report back on how effective they are in traffic (still a question about that). Also, I hooked up one LED module with both colors (red and yellow/green) to a wall wart and just let it run. The yellow/green got too hot and shutdown but the red keep burning. After I let the module cool off, the yellow/green LEDs came back on. So I think these modules will work for turn flashers or running flashers, but not as full-time running lights.

The whole mounting light structure is looking almost a bit too geek--I'll be thinking of ways to streamline the headlight/signal thing, if the turn flashers seem to make a difference.
http://monarch.gsu.edu/jeff/bike/wor...lashers_03.jpg

I put some pictures and windows avi files here.

vrkelley, my commute photos just started when it gets light enough to take pictures--we (my wife, son and I) usually leave the house about 7 am (in the dark). I have added the same headlight to my wife's bike, along with a rear strobe and car horn :D. My son has two Cateye TL-LD500 rear led blinkies and one Cateye HL-EL200 3-led headlight flasher. He rides between my wife and me. Sometimes I think all the blinking lights and strobes cause some people to go into a trance--I've seen people just sit (fortunately not moving!) and stare at the lights. :eek:

Awesome setup! Yeah maybe a housing for the lights might finish it off - like a motorcycle. The PVC pipe could get painted black some other color *since visibility probably isn't an issue* :D

For anyone who's interested here's Chris' Home lights and LED comparisons.
Chris started out with Geek-bike light, then decided to market LEDs that can do the same thing. He's been developing for 1 yr and here's his light comparisons.

http://www.solidlights.co.uk/features/bright.php

btw I may post this on the LED comparison thread also

interesting... what kind of halogen does he compare it to? an MR16 will appear brighter than an MR11, and better brands will appear brighter still, and higher efficiency brands higher still... there is no debating the bulb life, obviously. at over $300 USD for the 10W version (that is claimed to provide 30W worth of halogen light), it is still tough to compete on a cost basis with a 20W high efficiency MR16 halogen overvolted... should be able to get around 50W of "halogen light", a few hundred hours of bulb life, and at minimal cost (<$50 plus < $10 per bulb). At $450 USD for the 10W system, the comparison should be to professionally manufactured 10W HID systems. now, if he wants to post plans on how to DIY (no CMC or optics lab required) the 30W equivalent LED system for <$100, i'll be interested :)