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Discussion Starter · #1 ·
Hi there! I'm new to posting but been lurking MTBR for months for all sorts of stuff...

Anyway, I'm looking at building a tail light on the cheap that all it does is blink. No fancy modes or anything. Just switch on and have a steady blink. I'm posting this to get some opinions on what I'm thinking of doing, perhaps some insightful advice.

To keep it cheap I'll use a basic deal extreme driver. Then set up my 555 timer circuit to open and close a transistor. Here's my first question... would it be best to turn on and off the led driver itself or the output of the driver? Also, are there any cheap drivers that can take a signal to turn on/off like the buckpucks have?

For the lights I am looking for colored LED's, however I have a hard time finding any ones at high power like CREE XR-C. Does any one have a recommendation and where to get them, ideally US source? (BTW, I was also thinking about using 2 leds, one red one amber or something and make them blink alternating with a small pause between colors - this depending on the complexity, remember, cheap and relatively simple)

For the actual lamp I'm considering full getto. Just mount the LEDs on a flat piece of Al. Have the piece bent in between the LEDs with a slight angle. Then direct the right LED straight back such that the left one faces into the road a little. For the reflectors use a narrow/medium for the right and a wide for the left. This would give a nice non directional light.

What do you all experts think. This would be my first build so I am just piecing this in my head rather than from hands on experience. Also, if you're wondering why I'm going the 555 route is because I can put this circuit together for like $1.50 plus say a $4 driver is a lot less than a driver with modes, besides, this gives me the ability to not have to deal with switching through modes.

Thanks
 

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Best bet is to turn the driver on/off.
For a tail light probably run micropucks at 350mA, should be very very bright and powered by 2xAA. 500mA version is available too.
For optics there is a "flare" optic I think from LEDsupply that outputs a very wide/short beam, ideal. Combine that with a narrow 6-10degree optic pointing directly back should give a very good beam pattern. Not as bright as the dinotte but better all round viz.
Put all these together, hassles of housing, waterproofing, and $$$ get a cateye ld1100 instead!
 

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Discussion Starter · #3 ·
I guess that is true on the $$$. I just like to DIY stuff and this could be an easy first LED project as a warm-up to a real front light. Your is really well taken though 'cause when I get carried away with this stuff... The only thing is that I was hoping to drive like 750mA to make it very bright.

Is the Dinotte rear pretty directional?
 

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phx29er said:
I guess that is true on the $$$. I just like to DIY stuff and this could be an easy first LED project as a warm-up to a real front light. Your is really well taken though 'cause when I get carried away with this stuff... The only thing is that I was hoping to drive like 750mA to make it very bright.

Is the Dinotte rear pretty directional?
I looked into this a few months back because I had mounting issues for a conventional blinky(since resolved). 1 led at 350mA should be a hugely brighter than any blinky out there... I'm guessing dinotte level. I actually wanted a 100mA driver for mine because I thought 350mA would be too bright and runtime too short.
Hmm, thinking about the driver... red leds are 2.2v so running one off 2AA would need a buck driver whereas a white LED needs a boost, you can probably run two in series 4.4v like a white LED 3.5v
 
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