Designing good daytime rear commuter lights

cehowardGS

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I am a newbie on the bicycle, newbie on the commuting, newbie on the nightriding, and a newbie on lights. With that said, I started with a cheapo rear light out of wally mart. I have moved up to a Planet Bike Turbo Super Flash. Way ahead of the cheapo, but from what I have been reading in these thread, I am barely minimum!!

I am running a PB Blaze 2w up front, and a PB beamer on my helmet. Still, from reading this thread, I am barely minimum. That is good, because I am finding out, although fun, that riding in the night with traffic one has to be on that ball. It is fun, but it is no joke out there, and I see that I need to be seen.

Just joined this forum, and I joined to LEARN.. ;)
 

Savvas

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In order of posting:
Savvas - Yes microprocessors are for yuppies but when I was flirting with a more complex flash sequence they were the only way to go since you have infinite and rapid control over the sequence of loght flash as well as colour change and I was in the mood to play!
Since I already had the LED driver built it was easy to reprogramme it for the new slower sequence.

Thanks for the explanation. I'm keen on having a go at replicating your cigar light. Trouble is, I can't see the microprocessor on the circuit you showed us in post 208 (or thereabouts)! What am I missing...?
Savvas (on leave and in avoidance mode with a long list of house maintenance tasks!)
 

1 what

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Hi Sam,
Always happy to help a chap avoid household tasks!
It's a different circuit altogether.
I'll try to draw it (and post) later tonight.
Tom.
 

1 what

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Savvas,
Here is the cct using a picaxe 08M2 driving mosfets to turn the LEDs on and off.
picaxedriver.jpg

Both the R&Y LEDs had the same on/off sequence:
ON 0.1 sec - OFF 0.1 sec - ON 0.2 sec - OFF 0.1 sec - ON 0.4 sec - OFF 0.1 sec
The 2x 2.2 ohm resistors (by pure good luck) gave me a current of 740ma in the red CREE and 860ma in the 9 yellow LEDs.
I chose to run it all at 3.3V to minimize the voltage drop across these series resistors and max the efficiency.
PM me if you want further details.
 

Savvas

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i what,
OK - I can see now how I got confused! After abandoning your 'twinkle' light you've gone back to the 'cigar' model but elected to use the afore-said light's yuppie driver instead of the multivibrator! I've been refusing to learn about these 'picaxe' thingumys for years - I can see I'm going to have to spend some time with wikipedia!
While I thought the Enterprise was v/elegant (and I've been trying to copy it) the cigar model seems more practical in some ways. Is that a fragment of ping-pong ball at the end that you have the Fenix diffuser mounted on?
Savvas.
 

1 what

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Hi Savvas,
Yes – the “cigar” light with the “twinkle” driver.
The picaxe microprocessor is very inexpensive and very easy to use in this type of basic way (that’s a pun since it uses “basic” prog language) if you’ve had any electronics education. Well worth the day or so you might spend getting familiar with it (again - PM me if you want any help).
See:
http://www.picaxe.com/
plus Wikipedia.
I agree that the “Enterprize” is v elegant and it was hard to move on from it but the addition of a second colour plus the size increase worked better especially from the side. BTW I think you’re being polite calling the new light “cigar” shaped. I think it looks more like a flying p****** (Greek word rhymes with challis). I looked at modifying the earlier light to get some yellow LEDs into it but it would have wrecked it….pity.
The half pingpong ball is actually half the ball from a roll on deodorant. They are much more solid than pingpong balls and cost zip. They also make excellent diffusers.
 

jdp298

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They also make excellent diffusers.

This was going to be my observation. The obsession with ultimate million-lumen LEDs seems to over-reach itself. Commuting, driving and just watching what's going on, I've come to the conclusion that bright enough can be easily reached. What is less well done (it seems) is making the illumination big enough. An eye-gouging pin-prick of light is hard to place and easier to ignore, whereas a dimmer but wider source of light is much more quickly recognised. Look at the back of any motorcycle or scooter. They could easily reduce the size of these lights and make them brighter but don't.

My B&M standlight on the rear face of my pannier rack is degrading in standlight duration, its replacement might be the reflector and diffuser off a scooter with something a little more home-brew inside.
 

BrianMc

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This was going to be my observation. The obsession with ultimate million-lumen LEDs seems to over-reach itself. Commuting, driving and just watching what's going on, I've come to the conclusion that bright enough can be easily reached. What is less well done (it seems) is making the illumination big enough. An eye-gouging pin-prick of light is hard to place and easier to ignore, whereas a dimmer but wider source of light is much more quickly recognised. Look at the back of any motorcycle or scooter. They could easily reduce the size of these lights and make them brighter but don't.

My B&M standlight on the rear face of my pannier rack is degrading in standlight duration, its replacement might be the reflector and diffuser off a scooter with something a little more home-brew inside.

Multiple side-by-side lights look bigger, too. The Red Zone 4's showed that if you have the power, you can spread the beam and increase coverage while not losing visibility at a distance. So I removed the reflector from my DIYs and placed a narrow beam thrower (HotSpot) between. Distance and coverage. When the LEDs arrive I have a dyno tailight to build that will use a 15 x 90 degree FWHM lens on three LEDs, one aimed straight back, one to each rear quarter. The light/reflector will be the width of my rack. Under driven as a 1S3P in series with the headlight, it should be about 100 lumens into a 30 x 270 degree beam. We will see if that works well or not. :) BTW, some (not most) of the scooter lights here are pathetic, others are quite good. So size isn't everything. We also have to stand out from other light noise and be picked up by the subconscious of inattentive drivers. A bigger task than it was before cell phones.

BrianMc
 

jdp298

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Got there. the Lucas 525 motor-bike light. The fitting bolts are a thread-width wider than the standard holes at the rear of a rack, but we can get round that...

Got a half-watt red LED and my normal standlight circuit in there. Pictures here:

http://www.flickr.com/photos/jdp298/sets/72157626884852454/

The faceting of the inside of the lens makes anything diffuse. I went with the red LED rather than a white one because all the red plastic is essentially a red filter. All the other wavelengths from the white LED would be wasted. The width of the light is good, as is the depth of the sides; this makes me much more visible from the sides too. It replaces a B&M toplight standlight plus. It's much brighter, visible from a wider angle, lasts longer and still cost less than the B&M all in.

Tenner for the motorbike light off ebay and 18 quid for everything else from Maplin. Contrast with about 30 pounds from anywhere for the B&M thing, which has degraded to the point it won't stay on for more than 20 seconds now. I don't think I can justify selling it on ebay now, so it might get "investigated". <<smiles>>
 

Savvas

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Hi jdp298,

I recall posting the circuit for the B&M Toplight here at cpf sometime - I cribbed it from Olaf Schultz's site a while ago. It's a very simple circuit - quite similar to a lot of 'doodling' that appears here!

Savvas.
 

jdp298

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I remember seeing it. It was very simple. The current one has more components, way more components. I'm guessing they have a ZXSC310 and a timer cct in there. The brightness remains constant and used to turn itself off after 4 mins. Nothing conceptually hard, but I use vero-board which takes up more space.
 

Marcturus

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BrianMc

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Re: ATTN Brits who can count to four

^^ That light still being around makes me feel better about my satisfaction with my current set up and not proceeding with some designs I have the parts for but have not built.
 

Savvas

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It appears to be longer with the LEDs arranged linearly down its center (pictures from their web site copied to a service to avoid hot linking, but as this is not a commercial use, and having the cycling community familiar with the aftablasta, I think it fair use):






It looks like a linear array of red LEDs down the center line, and a cover a bit longer and wider than a film cannister.

Reviving old thread though maybe just briefly...

I have one of these. The whole thing is custom made out of some sort of high-grade industrial plastic, CNC turned to very fine tolerances (the black lid is an interference fit onto the lower part). Mine has 4 XP-E red LEDs arranged 2P2S and running off the ubiquitous 7.2v 18650 battery. Blindingly bright light with real presence! The LEDs are arranged on an aluminium strip heatsink attached to and projecting down the centre of the lower capsule.

Sam.
 
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angerdan

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BrianMc

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Update. Time flies when you are having fun! A lot of good commercial options in daytime-bright taillights now and that was not the case when I starts this thread. I have a Turbo Superflash on the back of the helmet, a Cygolite Hot Shot on the seat post, and LED by LITE: http://www.ledbylite.com/

I had a couple of wiring issues crop up, one in a taillight (off) and one in a headlight (shut off - bad + power lead connection), the handlebar switch for the LED by Light failed, but I run them solid on anyway, and two DIY battery packs finally failed after seven years, other than that, I have another couple of years on my lighting system.
Svex7E.jpg


The DIY rears are about as bright as brake lights. Still, in the day a fluorescent vest is more visible.
 

lumen aeternum

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They make LED light bulbs in red, with pretty much 360 degree spread. Could one take it apart and remove the 120 volt circuitry and make it work on Lion batteries at 3.7 x n volts?
 
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