I'd suggest 3AA battery and a switching regulator such ashttp://www.pololu.com/product/2122to really get the most out of your batteries.Make a standalone board if you want to cut down on external parts. Don't need much:'328P, 8 MHz crystal, 2 22pF caps, 10K resistor, 2 100nF caps.
Hello,I'm trying to use a Arduino nano, mini, or lilypad for a battery-powered wireless sensor application. I don't have any of these yet, so I'm looking for guidance.1) I can't tell from the schematic whether the nano, mini, or the lilypad have LED's built in. I would definitely not want an LED.
3) When the spec on the Arduino that VCC could be 2.5 to 5V, does that mean the digital output voltage also floats with vcc, or does that mean it will regulate the digital output voltage to 3.3, regardless of vcc?
4) I've also considered building my own Arduino clone so I can minimize the power draw, not have any LED's.
If I stick with three AA batteries, I'll need a 3.3V power regulator for sure. How do I wire it up so that the regulator isn't always sucking power from the Arduino?
I've had great success hacking Pro Minis for this.If you remove the power components (marked with red crosses below) you get a little 16MHz Mega328 board which sleeps perfectly. It's 30 seconds work, just poke the unwanted components with a soldering iron and they fall right off. Much easier than building your own.You can program the chip via the ISP connector or via FTDI if you jumper Vcc on the FTDI connector to the Pro Mini's Vcc under the board (the green line in the image below).
Wow, thanks for the tip. Can I ask what the components in red are? Are you taking about the built-in (less efficient) regulator, and powering the Arduino Mini directly from 3xAA battery at about 4.5V? Does that work? Is it still running at 16MHz? I'm wondering what the other parts are. If you wouldn't mine describing it, I'd appreciate it.
I think if I want to run a 8MHz, I'd need to build my own Arduino right? I can't make the Arduino Mini Pro run at 8MHz because it's already got a built in 16MHz oscillator?
But ... if you're going to do that you might as well use a bare Mega328 chip - you're not using _any_ of the components of the Pro Mini. Mega328 s can run at 8MHz with no external components.
haha, yeah. It's just weird the economics of ebay. A Mega328 with or without the bootloader is about $3.50. Same price as the whole Arduino Mini pro. You'd think they sell the bare chip for cheap(er).