October 12, 2010
I've been messing around with animation & programming lately, and I'm wondering what I might do w/ these micro-controllers. Hoping to get some good ideas from the rest of you guys!
Learn to use Arduino's and get some ideas for what to do with them.
Wish they met more often, and closer to where I live!
Hi April, it was great to meet you at the meetup last night, and especially fun to meet a fellow ex-Californian! :)
Thanks for letting me know that my posts are indeed reaching the list.
Okay, two issues with using the lilypad to drive the strip:
- The lilypad is using 3.3V logic, so I guess you'd need a converter to get it to effectively talk 5V: http://www.sparkfun.com/products/8745
- The lilypad uses a slower clock than the Uno and such, but I doubt that it's impossible to adapt the library to the slower speeds.
Given that, it seems that it would be best to at least initially plan on using an Uno or Pro Mini. It looks like they also got away with using 4 NiMH AA's raw.
Blerg. I'm failing to trivially find a beefy 5V voltage regulator kit. I'm curious if that means that it's as simple as running through an arbitrary large 5V voltage regulator, or if it's more complicated than that.
I would recommend throwing that question to the meetup group as a whole. Something like: "Does anyone have a recommendation for a board or kit that would fit on an umbrella that would take ~6V and drop it down to 5V with ~8A max current?"
Oooh, the lilypad's voltage regulator is tiny. Trying to run that much current through it is a magic-smoke moment waiting to happen. Well, I haven't tried using them solo before, but I _think_ it's somewhat straitforward to use a voltage regulator.
Ultimately, the voltage regulator needs to pass the thumb-test (can you tolerate holding you hold your thumb to the part wiout getting burned?).
Also, for these sort of calculations, I find using Wolfram Alpha with verbose units to be exceedingly useful: http://www.wolframalpha.com/input/?i=...)
If I remember correctly, the lilypad's voltage regulator lives on the battery-holder board, right?
I hope tht helps!
So, at half current draw (dimmer lights), or using 2 parallel sets of 4 batteries in series, you'd get about 30 minutes using 2000 mAH batteries. (alkalines will average higher than that, see the wikipedia page for comparison)
Ultimately, my recommendation is to try using the size of arduino you want (even small), and leech the led power off the arduino's voltage regulator. Now, the higher the supply voltage (say, the 6V from 4 alkalines), or the bigger the dra on the leds, the hotter *cont.*
Hmm, I guess I would look at keeping it simple and use AA batteries. If you're using a basic "big" arduino, then the voltage regulator already on the board will probably do just fine for throwing away the excess voltage from using 4 AA alkaline batteries in series. That is, 4 AA's in series generate ~6V for alkaline, and ~5V for rechargeables.
So, at maximum 7.6A, just the 4 batteries would last about 15 minutes.