# $65 Dinotte 400R alternative? (headlight as a tail light)



## atreyu (Oct 19, 2012)

*$20-$30 Dinotte 400R alternative? (headlight as a tail light)*

(Was a $65 project... updated directions and prices below make it a $20-$30 project!)

Being a husband and dad has motivated me to "stack the deck" in the safety department... at a reasonable cost wherever practical. So... reflective triangle, XM-L U2 headlight, Airzound bike horn, helmet-mounted Planet Bike Blaze 2W and Superflash Turbo. All feel reasonably well-balanced in the cost/benefit dept.

Last item on my checklist: a truly daylight-visible tail light. Are you $%^& kidding me?!? $220 for a 300 lumen Li-ion 400R? $230 for a 500 lumen DS-500 (when available)? Why have high powered tail lights not come down as much as high powered headlights have?

Spurred by that last thought, I started looking into using a headlight as a tail light, and found a mod in this thread. Inexpensive, but it little _too_ "DIY-looking" for my taste, plus I was concerned about how waterproof it would be. So I tweaked and updated the mod to be tidier and hopefully easier. (Jump to post #8 for a beam pattern photo):

Here's what I bought:

~$14-$20 (was $40 when I bought it!) - CREE XML T6 Bicycle Headlight -- brighter and cheaper than the light referenced in the OP. It's 1200 "wink-wink lumens," don't know how many "real world lumens" that is. It's dimmer than my XM-L U2 based Magicshine MJ-808U, but not by _that_ much. Like most of the cheaper Magicshine clones, it comes with a non-waterproof Li-Ion battery pack & charger, and rubber "O" rings for handlebar mounting... _unlike_ some of them it also comes with a head (not helmet) mount, which saved me an additional purchase... I used the head mount bracket to mount the light. Some of the Amazon sellers are free-S&H/Prime eligible.

$5 - Wide Angle Lens -- bought this just in case, but it turns out it's crucial for this project. The headlight above has a standard smooth (i.e. not orange peel) reflector, and in its stock form it's WAY more "spot" than the MJ-808. (Thanks to logman for pointing out this new *RED* wide angle lens -- wish I'd seen this earlier! Modifying my steps accordingly...)

Part no longer needed if you buy the *red* wide angle lens! $15 - Tiffen #25 Red Filter, 52mm -- kudos to OP for this idea... it's the perfect size. You might also use red tail light lens repair tape, don't know how that would compare in light transmission/appearance/durability.

~$5 - Devcon 5-minute Epoxy -- also available at any hardware store... this stuff is AMAZING, I now use it for nearly every gluing job. Firms up in 5 minutes, dries clear & waterproof, 1500 psi bonding strength, two-part mix-and-use formula means it doesn't harden before you need it to.

$0 - A couple of zip ties. We all have some of these already, right?

Assembly:

1) Swap out the stock lens for the *red* wide angle.

2) Step no longer needed if you buy the *red* wide angle lens! Epoxy the large "O" ring to the part of the housing around the lens, taking care not to drip onto the lens itself. This was my idea... the ring is perfectly-sized for the task, and provides a soft cushion between the lens and the light body. I had visions of the filter cracking after a particularly strong shock if I'd taped the filter directly to the metal light body as in the two other examples I've seen. I erred on the side of too much epoxy... filling every little nook or gap a couple of times over to make sure it was watertight.

3) Step no longer needed if you buy the *red* wide angle lens! Epoxy the red photo filter to the "O" ring, then apply a substantial amount of epoxy, making a continuous waterproof seal/sleeve from the filter's metal ring to all the way back over the front part of the light housing. I found it easiest to do this with the filter face down on a sheet of paper. Stop short of the threads (i.e. just short of the color switch from silver to black), or you'll be unable to open the housing to swap out the reflector, lens or LED in future mods. Again, I used extra epoxy to fill every little nook.

4) The Li-Ion battery is shinkwrapped but has exposed paper ends... "boom" in the rain! Instead of buying a $15 can of Plastidip and later struggling to squeeze the rubberized battery back into the nylon holder, I used epoxy. Set the battery on the flat end (cable protruding from the top), and pool epoxy on top of the paper and wrapped-around plastic wrap until the end is level (other than the cable). Let it dry for a half hour, then invert the battery (I clipped it to a ceramic mug so the end was level, as it woudn't stand on the end the cable comes out of) and repeat the process on the other end. Voila... waterproof battery!

The epoxied battery... originally the stiff blue shrink wrap puckered up around the exposed red paper. I filled the gap the cable leaves in the shrink wrap, then covered all the paper and the part of the shrink wrap around the top, leaving a level surface:

5) Cut the straps off the head mount, use zip ties to secure it upside down to the horizontal part of your seat rails. Mounting to the diagonal part of the rails results in a light that aims too high or too low, in my experience.

6) Attach the light to the mount using the small "O" ring, secure cabling and battery holder. Done!


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## Harold (Dec 23, 2003)

sounds like an interesting project. got pics to share?

I use a Magicshine taillight I got from Geoman a couple years ago. I like the brightness, but not a fan of the fact that it doesn't have a consistent blink setting. All the settings are irregular some way or another, or just always on.

at night, I am always given tons of space. I don't tend to run it during the daytime unless it's a dark, cloudy, dreary sort of day.

I make use of plenty of reflective tape to augment my active lighting. I also have reflective rims and tires with reflective sidewalls. While the reflective stuff doesn't do much reflecting during the daytime, my bike is a red/white/black color pattern, so I have a contrasting color scheme that's a little more noticeable.


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## atreyu (Oct 19, 2012)

Here's another photo of the mounted light, giving a better idea of the size:










I'll take a couple of photos of the light pattern when I'm not watching my Giants in the World Series!


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## BrianMc (Jan 5, 2010)

A wide angle light as bright as brake lights in the daylight should get the job dome without being excessively blinding to following traffic. I use twin XM-L's in my headlights for about 1800 lumens on high. Cutting out all but the red light might cut that to 200-300 lumens for single XM-L. I get about 220 lumens out of these:



Cost me $40 but does not flash, and I piggy back them on my headlamp water bottle pack with 4-9 hour runtime for both depending on whether the headlamp is in flash mode or not. Yours is a lot easier, My videos should be close to what you can expect.

With sun behind "driver" looking at Pickup brake and tail lights and the DIYs with twin Radbot 1000s under them.

ImageShack® - Online Photo and Video Hosting

A ride to 1/4 mile away and back (cheap low res camera):

ImageShack® - Online Photo and Video Hosting

Light is coming from behind rider (late afternoon, riding East).

Proof of concept: I get 95% of drivers giving me more room (done as counted surveys of those moving out of the lane or left in the lane versus not moving at all while riding the same stretch repeatedly with different taillights). About 1/5 the rate I have with a RedZone 4 (200 lumens, wide on high, flash) and a Hotshot on pulse or a Turbo on flash. So I am remounting my DIYs.

Looks like I need to use the new camera to get a better resolution ride away video. Maybe you wish to get one of your DIY. Anyway, that gives you some idea of 200 lumens on constant with twin Radbot 1000's, Still detectable in this low res video at 1/4 mile.

Leopold Porkstacker has a pair of taillights each putting out 300-400 lumens, one with a wide lens one not. Look up Another Commuting thread about lights for more info. He needs that in California to burn through the haze of weed behind the dark tinted windshields. 

Nice work, BTW.

BrianMc


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## Sanath (Jul 20, 2012)

NateHawk said:


> sounds like an interesting project. got pics to share?
> 
> I use a Magicshine taillight I got from Geoman a couple years ago. I like the brightness, but not a fan of the fact that it doesn't have a consistent blink setting. All the settings are irregular some way or another, or just always on.
> 
> ...


I thought irregular was the way to go with flash patterns, so as to get peoples' attention.


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## woodway (Dec 27, 2005)

The Dinotte lights are really expensive. But they are really good lights, bright, reliable, durable as hell and if something does go wrong Dinotte customer support is top-notch. I view purchasing these lights as a multi-year investment in my safety. I have a four year old Dinotte 140L taillight that I run day and night year-round. I winced when I bought the light and battery for over $200. But four years later all I care about is that the light is still working great and drivers are giving me plenty of room even in full sunlight.

Your light looks cool. Hope it works great and thanks for sharing the photos!


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## atreyu (Oct 19, 2012)

Thanks for the compliments!

Yeah, I was torn... came close to pulling the trigger on the $130 400R-AA before I considered this option and started researching/brainstorming. I _really_ wasn't looking forward to having to shuffle more NiMH's around than I already do, but at those absurd prices I was only willing shell out $130 if it was the cheapest truly daylight-visible option -- paying $80 more for Li-Ion was out of the question... too out of line with my value-loving sensibilities.

And hey, Dinotte... don't think we haven't noticed that you've only dropped the price of your 400 tail light about $40 since it was introduced 4 YEARS AGO, without (as far as I can tell) any major new innovations!

I'm pleased with my solution... I have the convenience of Li-Ion, it's truly daylight-visible, I've ridden in heavy rain two days in a row with no issues, and the light is staying aimed in the direction I want it aimed, despite going over bumps at high speed.

(removed less-than-ideal set of comparison photos... see next post for better comparison shots)


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## atreyu (Oct 19, 2012)

Ok, here's a good set of beam pattern photos. I set the exposure for my modified light, then locked all exposure settings and switched to my Planet Bike Superflash Turbo (the newer 1W version). I tried to adjuste the exposure to approximate how this looked in real life... of course I adjusted the exposure by the same amount for both images.

These was taken in a pitch black conference room, at a distance of ~21ft. The overhead projector screen on the wall is ~9ft wide, so the "hot spot" is maybe 13ft. This means that the hot spot is just over 1 foot wider per 2 feet of distance.

I'm pleased at the amount of halo around the hot spot, by the way... should translate to decent off-axis visibility, which is what I saw in an informal daylight walk-around the day I installed it.

First, the PB Superflash Turbo:









Next, my "Epoxied Wonder":


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## BrianMc (Jan 5, 2010)

This is at twelve feet, So at one car length (20 feet), the bright spot will be at least a lane wide. That should prevent too close an approach, which is very unsafe given that is within any driver's reaction time, if a cyclist suddenly stopped for any reason. 

I wondered about those lenses before. Sending the light through another lens is going to cost about 10%-15% of the output, but when it redirects the beam this effectively, that is just fine. The hot spot will be larger the farther back. Even Ferrari driver's eyes will be higher than the bottom edge, I wonder if you should tilt the light up a hair to catch truck drivers closer in. OTOH: This setting will work well as you slip over a crest of a hill with a sports car following and the driver just seeing you. So it depends on your traffic and terrain. 

BrianMc


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## fightnut (Jul 5, 2007)

:thumbsup: Very nice atreyu!


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## pethelman (Feb 26, 2011)

atreyu said:


> Last item on my checklist: a truly daylight-visible tail light. Are you $%^& kidding me?!? $210 for a 300 lumen Li-ion 400R? $270 for a 500 lumen DS-500 (when available)? Why have high powered tail lights not come down as much as high powered headlights have?


This is exactly what I thought as well, and why I never purchased a 400R over the years, even though it was clearly superior to anything else. However, over two years of design work and process development building the DS-500 and getting it to a level of refinement that had a high degree of flexibility and reliability (day/night and various mounting scenarios) taught me that the 400R was actually NOT overpriced at all. Sure, you can home-brew for much less. Many do, and can achieve fine results, such as your cool solution here. However, in the case of the DS-500, low-rate production with all US-made components absolutely demands the higher prices, or it's simply not worth the time to build them. I wish I could make them for much less, but it's a physical impossibility in the US. The Chinese products have conditioned us to assume that bike lights should be dirt cheap. I pay roughly $35 a piece, JUST for the electronics boards (TaskLED drivers), and at the same time, you can find some entire Chinese-made light systems for just a little more than that. :madman: My philosophy was that if it was going to be expensive, then it needed to be really, really good, and at the end of the day, there's definitely a niche market out there for such a product.


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## atreyu (Oct 19, 2012)

Thanks for the reply, pethelman.

You're not going to get any argument from me on one point: the DS-500 is in a whole different league from my homebrew light, and from the 400R, for that matter. There's a reason my post title says this might be an alternative for the 400R, not the DS-500. Before going this route I saw several impressive DS-500/400R comparison videos on YouTube... if my internal "value gauge" were calibrated differently I'd have bought your product in a heartbeat. To be honest, I was still *somewhat* tempted to make an exception, but of course the DS-500's temporary unavailability settled the matter. I'm particularly impressed with the off-axis and side visibility.

When it comes right down to it, however, what I most need is front and rear visibility with decent off-axis visibility... my initial assessment of my light is that with the wide angle lens installed, the daylight rear and off-axis visibility are well into "good enough for me" territory.

As far as the 400R goes, I'm not going to be as charitable as to the DS-500... it may not have been overpriced when it was introduced 4 years ago, but I have trouble with the fact that the price has dropped only about $50 since then. They're obviously a bigger shop than you are, yet as far as I can tell they've made no significant strides in brightness, efficiency or design... and I'd be shocked if their LEDs, PCBs (or equivalent parts) and Li-Ion cells haven't gotten _much_ cheaper since then. If I'm wrong about any of that I'm happy to be corrected.

Anyway, I guess time will tell how well my project holds up... I'm hoping that the fact I commute exclusively on paved paths (and don't have time for "real" mountain biking) will help extend its life.


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## pethelman (Feb 26, 2011)

atreyu said:


> When it comes right down to it, however, what I most need is front and rear visibility with decent off-axis visibility... my initial assessment of my light is that with the wide angle lens installed, the daylight rear and off-axis visibility are well into "good enough for me" territory.


Thanks atreyu! You're to be commended on your ingenuity and desire to try to something new. In fact, that's how the whole DS project evolved, followed by some friends encouraging me to pursue it a bit further. Actually, I think I agree with you that the Dinotte cost to manufacture is probably significantly lower than mine. However, it's only been in the last couple of years that doing something like what you've done here has even been possible. Prior to the magicshine revolution, DX.com, etc., pulling off a nice DIY, high-output taillight similar to the 400R would have been quite costly indeed. No doubt ALL of the high end manufacturers are feeling the "heat" so to speak, from the flood of low-cost lights.
Cheers


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## logbiter (Dec 30, 2003)

Cool project! 
I recently noticed that Action LED now has a red wide angle lens, so you could skip the tiffen filter! It wasn't there a few weeks ago when I ordered some stuff from them.
I was thinking about doing something similar, especially since I've been pulling my 4 yr old to school on his trail-a-bike. We both sport some super flash lights on our helmets, but that's it so far.

My only 'problem' is not having a good place to mount it on the trail-a-bike since my son's seat is slammed all the way down. I haven't got creative about it yet, but was thinkin' I can create standoff bracket without much problem.


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## atreyu (Oct 19, 2012)

logbiter said:


> Cool project!
> I recently noticed that Action LED now has a red wide angle lens, so you could skip the tiffen filter


HAH... DOH! Well how about that... I did _multiple_ searches for red lenses before I committed to this solution, to no avail! I didn't check Action's website, though... I got the clear wide angle through Action's Amazon storefront, not realizing they sold direct, too.

Oh well... hope my easy mounting method will help a few others, as well as idea of epoxying the ends of the battery pack. I guess if by some chance I spring a leak into the space between the red lens and the wide angle I'll grab one of these red wide angles.

Hope you find a mounting solution for your kids' bikes... please share if you do! I have a 6yr old and a 3yr old, so I'm aware of how little "accessory space" there is on those bike!

I wonder... might one of these "bar extenders" work? I'll bet this would also be an option for adult bikes that already have an under seat bag... actually, I removed *mine* to mount this, maybe I'll try it myself!


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## brewrider (May 30, 2012)

I ordered the red wide angle lens to put on a cheap XM-L, and I'm very happy with it. It's still VERY bright even with the red lens. Very visible in direct sunlight, especially on flash. I think it would be a bad idea to have it on flash at night because it's so bright and disorienting. I can't imagine needing a light brighter than this.

The only problem now is how to mount it. I use a saddle bag on my road bike and a trunk bag on my other street bike, so hanging it from below the saddle isn't an option.


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## atreyu (Oct 19, 2012)

It has been about a year since my initial post, thought I'd post a follow-up. Reviewing the product links, I see the price of the light I used has dropped from $40 to $22, making this project only $35, vs. the $65 I initially spent!

I wound up buying the red wide angle lens that's part of the current instructions, and removing the Tiffen filter that was part of the initial project... having one lens instead of two has definitely increased the light output from when I took the light beam photos above.

The 1yr report: I've commuted on my bike nearly every day, rain or shine, and have ridden through violent downpours without any incident or light interruption... the battery, charger, light and mounting hardware have held up with no noticeable degradation. 

I run the light in flash mode in daylight, and in solid (high power) mode when it gets dark. I can definitely tell I get a lot more space from drivers than I did before I installed the light, and I've gotten a decent amount of positive feedback from drivers and fellow cyclists. 

Most memorable was a pre-dusk exchange at a stop light, with a shuttle bus driver who'd pulled up in a right turn lane next to my bike lane. He grinned at me through his open window, so I asked, "Could you see me from pretty far back?" He nodded enthusiastically and said: "Man, you look like a frickin' AIRPLANE!"


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## MS150Rider66 (Feb 10, 2010)

pethelman said:


> This is exactly what I thought as well, and why I never purchased a 400R over the years, even though it was clearly superior to anything else. However, over two years of design work and process development building the DS-500 and getting it to a level of refinement that had a high degree of flexibility and reliability (day/night and various mounting scenarios) taught me that the 400R was actually NOT overpriced at all. Sure, you can home-brew for much less. Many do, and can achieve fine results, such as your cool solution here. However, in the case of the DS-500, low-rate production with all US-made components absolutely demands the higher prices, or it's simply not worth the time to build them. I wish I could make them for much less, but it's a physical impossibility in the US. The Chinese products have conditioned us to assume that bike lights should be dirt cheap. I pay roughly $35 a piece, JUST for the electronics boards (TaskLED drivers), and at the same time, you can find some entire Chinese-made light systems for just a little more than that. :madman: My philosophy was that if it was going to be expensive, then it needed to be really, really good, and at the end of the day, there's definitely a niche market out there for such a product.


 Yes I agree with you! I am One of your very very happy customer! From your first ones you began a few years back.I have the DS-500 and DS-1200 and it's still going strong! I had a rough crash a couple of weeks ago and not one broke off. The rear light is mounted on the left seat stay the same side I went flying over the bike. Also I have no kickstand and bike has fallen a couple times and I have been fortunate. Thank You so much for your hard work on your products.


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## MS150Rider66 (Feb 10, 2010)

brewrider said:


> I ordered the red wide angle lens to put on a cheap XM-L, and I'm very happy with it. It's still VERY bright even with the red lens. Very visible in direct sunlight, especially on flash. I think it would be a bad idea to have it on flash at night because it's so bright and disorienting. I can't imagine needing a light brighter than this.
> 
> The only problem now is how to mount it. I use a saddle bag on my road bike and a trunk bag on my other street bike, so hanging it from below the saddle isn't an option.


 Hi this might be too late, but Dealextreme.com has different flashlight type mounts for bicycles and you may be able to find one to mount on your seat stay


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## steelhmr (Sep 30, 2011)

Have you looked into light heads that have more of a slow 'pulse' pattern when on flash mode instead of the usual 'strobe' frequency? 1-2 flashes per second instead of 10+? Flashing lights will always grab more attention than steady state ones. 

This build is fantastic. Absolutely love the beam pattern. Great job.


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## pethelman (Feb 26, 2011)

MS150Rider66 said:


> Yes I agree with you! I am One of your very very happy customer! From your first ones you began a few years back.I have the DS-500 and DS-1200 and it's still going strong! I had a rough crash a couple of weeks ago and not one broke off. The rear light is mounted on the left seat stay the same side I went flying over the bike. Also I have no kickstand and bike has fallen a couple times and I have been fortunate. Thank You so much for your hard work on your products.


Just now seeing your post here. Very glad to hear that you're still enjoying the lights and that they're holding up well to real world scenarios. Hopefully you didn't get hurt too badly in the crash. If you ever need any help with them, be sure to drop me an email! Thanks again.


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## BrianMc (Jan 5, 2010)

The lower output XML is likely warmer in color output (more red) than the MagicShine so that 1200 lumens (which is really about 900 to start with), and about 40% will pass the red lens so darn close to 400 lumens. If it is a whiter bin XML, it will be lower, but will be no lower than 200. Pretty nifty.


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