Arduino Mini (3.3V) + Li-ion battery

Development Boards Arduino
1

tl;dr - Easiest, smallest, and most cost efficient way to power an Arduino with a rechargeable battery, so the battery can also charge when plugged in.

I am fairly new to Arduino, and circuitry in general. For this project, I simply need one arduino to send a signal to another, and vice versa. When a button is pressed, a light and sound should go off on the other arduino. The Arduinos must be battery powered, and send signals to each other wirelessly. Cost and size are very important factors. The Arduino Fio is almost perfect for the job, but I need something even smaller and cheaper. So far, these components seem like the best choice:

Arduino Pro Mini 328 - 3.3V/8MHz: https://www.sparkfun.com/products/11114

Polymer Lithium Ion Battery - 400mAh: https://www.sparkfun.com/products/10718

Lithium Ion/Polymer USB Battery Charger IC - MAX1555 https://www.sparkfun.com/products/674

NRF24L01 2.4GHz Wireless Transceiver Module: http://dx.com/p/nrf24l01-2-4ghz-wireles … ack-149483

Would something like this work? I know that the biggest problem with powering arduino with Li-Ions is that most arduinos use 5V and not 3.3V, so this mini seems like it would work perfectly. I found a tutorial on how to use the nRF modules, so that shouldnt be a problem, but I have absolutely no idea about how to connect the battery to the Arduino through this IC.

What I would like to have in the end is a mini-USB port that charges the battery and can also upload sketches to the Arduino.

Any help or input is greatly appreciated.

2

Do you really need an Arduino ? What does it do for you ? How are the “light and sound” to be generated ? Simply transferring a pressed button from A to B or B to A could be done with a pair of XBees.

3

Wow, I didnt know you could do this! All I need is for each module to have a button, LED and a buzzer. When the button on one is pressed, the LED and buzzer goes off on the other one. Using just the Xbee would be a much cleaner solution. I did some research, and I couldnt find much that didnt involve the arduino. How do you program these Xbees? Im asking because although my inputs and outputs are simple, the timing has to be quite precise (delays and such). Are there any good tutorials online? Also, I read that the xbees themselves couldnt take a LiPo battery safely. Would I need a step down converter in that case?

As for the arduino approach, I figured it would be much easier to use this instead of the IC that I posted above:

https://www.sparkfun.com/products/10401

4

For simple, cheap, reliable and self contained RF remote control modules, take a look at the offerings here:

http://www.rentron.com/rf_remote_control.htm

The simplest solution for a light and a buzzer is here (schematics are linked in the page):

http://www.rentron.com/remote_control/T … t-pack.htm

5

Another very simple solution is to use these:

http://www.adafruit.com/products/1095