so im working on string of lights being controlled by an arduino micro or atiny if i can get one lol. Can i use a 7.4 v battery to the arduino? then run the lights power off the board? or what is the simplest way to get 5 volts out of a lipo?
7.4 will mess up the arduino. Use liion
oh well thats good to know what voltage do liions put out?
well ill check lol
Some arduinos can take more than 5v in, they have an onboard regulator to adjust the voltage - you should really check whether or not the board you have can handle other voltages (and what range).
As for the leds - some 5v led strips can tolerate higher voltages as well, though this is more trial and error for finding out, and I don’t recommend it. For 5v out of a lipo, i might suggest something like this http://www.adafruit.com/products/1385 - or one of the other buck converters on http://adafruit.com. Something like this (a more active converter than just something that burns off excess voltage as heat) will be a bit more efficient and get you a bit more battery life out of your setup.
well i have a micro and it shows up to 13v if i remember right
I use 3.7v liion with pretty good results. You can find batterys with chargers really cheap on ebay. I think the ones I bought were fot a rc helicopter.
actually the micro is 20v but wont the 5v ws chiped leds not work with the 3.7?
sorry i didnt say i wanted to use 5v ws2811 strings
20v really? Havent seen that one yet. I run a 5v . Ws2812’s work great. A liion battery is 4.2 when fully charged.
That makes things soooooooo much easier thanks guys
I also have good luck using usb battery packs from ebay they cost like 5.00 and you can take them apart to make them smaller. Plus they have thr charging circuit.
You mean like emergency chargers?
Didn’t even think about that lol
The Uno can take a 12v supply and has a pin which supplies Vin (whatever you’re inputting) and another one which supplies 5v. This can be pretty handy!
The one thing to be careful with the UNOs inboard regulator is that it is possible to draw more power than it can supply which at best will cause it to overheat and at worst, blow out!
I’ve run strings and controller from 4.2V down to 2.8V (strings were LPD8806 flavor which claim voltages down to 2.7V). When the battery voltage reached 2.8-ish, the lights started to flake out so I stopped the test.
However, I would not run anything below 3.5V, ideally closer to 5V to get the proper signal square waves, otherwise you’ll get some funky failures. I can vouch for that. 