Power Source for Bicycle Light project (video)

Forum 2005-2010 (read only) Hardware Interfacing
#1

Hello I'm seeking some help picking a power source for a project. A quick rundown: I'm designing a bicycle light system for nighttime safety that will include passive lights, turn signals, and brake lights. I am controlling 9 Bliptonic LEDs: http://www.bliptronics.com/item.aspx?ItemID=86

with a Picoduino nestled in the frame: http://themakerspace.com/testsite/index.php?main_page=product_info&cPath=1&products_id=2

I've got all the preliminary work done, here is quick demonstration: http://www.youtube.com/watch?v=e7dUXa_Sv8g

Anywho, I want to put it in the bike now but I don't know what power source to use for the project. I was thinking of connecting 3 AA batteries in series which would get me to 4.5 volts (close enough to the 5V needed for the lights yes?). Also, do I connect the power to the 5V and Ground nodes on the picoduino? Thanks!

#2

Batteries are a pain on bike lights. They always die at the most inconvenient time.

So my preference would be for a rechargeable battery trickle charged from a charge point next to where you keep your bike (hook it up every night) without having to remove the batteries.

Or something akin to the old dynamos that you used to be able to get for bikes. These had a small wheel in contact with the rim of the wheel that lit the bulbs. However, as so as you stopped (say at a busy road junction to turn across the traffic) the lights went out. Great!

But if you can find a nice hub-dynamo to charge the batteries, then thats a good solution.

#3

do I connect the power to the 5V and Ground nodes on the picoduino?

Yes. :)

#4

Haha to be honest I was hoping to just have the batteries last long enough to present, but that rechargeable idea sounds really good.

To clarify, I was more confused about what combination of elements should I use that would give this setup the voltage and amperage it wants.

#5

Bump please :)

I would still appreciate a specific power source suggestion, as opposite to a genre suggestion. If the battery can survive for a long duration that's a plus but I really only need it to last long enough to present the project.

Thanks!

#6

Bump please

OK. Bump. Bump. Bump.

If the battery can survive for a long duration that's a plus but I really only need it to last long enough to present the project.

And how long would that be? 3 minutes? 3 hours? 3 months? 3 years?

You can read how much current each LED takes. You can just about ignore how much current the Arduino takes.

You can read what voltage the LEDs take. You can read what voltage the Arduino takes.

It doesn't take a rocket scientist to add up the amount of current needed, and multiply by the length of time needed, to get the Ah rating of the battery needed. How much of a safety margin you want is up to you.

Then, it really isn't that difficult to find a battery with the required voltage and Ah rating that you need. If there is nothing convenient, you can use multiple batteries of smaller Ah or lower voltage, depending on how you connect them.

If you have a SPECIFIC question, come on back.

#7

Whatever battery you use, put a fresh one in just before the demo, and bring a spare with you too.

#8

Whatever battery you use, put a fresh one in just before the demo, and bring a spare with you too.

Belt AND suspenders! Always a good idea during a demo.

#9