I've played a bit with Arduino and 433MHz transmitters a few years ago : I just recorded the signal that open the portal of my residence then played it back and successfully opened portal... yaaay \o/, I also played with motors thanks to shields etc.
But right now I have a new project involving programmable and adressable LED Strips. I've searched the internet about what I can buy and it seems the majority of LED strips (on Adafruit at least) work at 5V.
Arduino takes 5V as an input too IIRC.
So my question is :
Is it possible to power an Arduino and a LED strip (approximately 50cm or 1meter), with a 3.7V LiPo battery ?
Can the Arduino output a regulated 5V, from the 3.7V provided by the battery ?
(I think I'll go one of the tiniest versions, or even just use an Arduino to program an ATtiny/ATMega - I don't know which one would be good to control LED Strips - stuck on a breadboard. If you have any advice about it, I'll take it too)
If no, what could I do which would be cheap and tiny, to up the battery voltage to 5V so it can power the Arduino & the LED strip ? Or.... should I instead buy regular 1.5 Volt (1.2V for NiCd) rechargeable batteries and use 4 of them in series to get roughly 5V ?
Hexalyse:
Is it possible to power an Arduinoand a LED strip (approximately 50cm or 1meter), with a 3.7V LiPo battery ?
Can the Arduino output a regulated 5V, from the 3.7V provided by the battery ?
LarryD:
Buy an inexpensive 'DC to DC boost' step up voltage regulator power board, search eBay or Pololu.
I've just searched for these things but it seems most of them (at least the one who output 5V on a convenient USB port) only go up to 500 or 600mA.
But if I need to power, let's say 30 LEDs (1/2 meter), at 60mA each, it would require 1800mA + the Arduino power draw.
So... it wouldn't be a good solution, am I right ? Or am I missing something ?
EDIT : After some research, it would seem a lot easier to just rely on 4xAAA NiMH batteries, giving a roughly 4.8V output, which would be good for the arduino and the LED strip.
So, I think I'll go this way.
I've seen that the "Powerboost 500" (or 1000) from Adafruit is really cool too : act as a charging interface as well as a boost to get 5V from a LiPo.
But at 20€+, it's not really worth it versus cheap NiMH batteries, so I think I'll go the NiMH route.
Last question : do I need a little circuit to prevent over-discharging the NiMH batteries if they power an Arduino (I'll go with Adafruit Trinket) + LED strip ? If yes, what is it called/where can I find it ?
Or can I just use it like this and anyway the LEDs/Trinker would shut down or show problems way before the batteries are damaged from over discharging ?
I assume using a wall wart is out of the question.
You could design a cct. where you push a button to power up the unit, when the battery voltage reaches a certain level, the batteries are the disconnected.
See 'Battery University' for NIMH battery information
LarryD:
I assume using a wall wart is out of the question.
You could design a cct. where you push a button to power up the unit, when the battery voltage reaches a certain level, the batteries are the disconnected.
Yes, it would be a portable device, so wall wart is not an option.
I've ordered rechargeable NiMH batteries. I'll try with 4x1.2V=4.8V, and it should run just fine. I've even read on the NeoPixel wiki that 3.7V seems to be enough to power a low number of LED (I guess 30 is low ?). I have a charging/discharging circuit for Li-Ion batteries, so I may even try to switch to a flatter 3.7V Li-Ion instead of NiMH and see if it makes a huge brightness difference.
Overdischarging doesn't seem to be "so" damaging for NiMH.