How to connect sensors to an Android device?

Question

I need to build a device, which measures several parameters (body temperature, conductivity and pulse) and transmits them to an Android mobile device.

The system has following parts:

1. The sensors
2. Sensors -> logic unit connection
3. Main logic unit
4. Main logic unit -> Android device connection

I intend to use IOIO Mint as the main logic unit and Bluetooth as "Main logic unit -> Android device connection".

Now comes the problem - I need to place the sensors close to the human body such that they are easy to wear. Probably, the sensors will be located at a different part than the main logic unit (the former - attached to the skin, the latter in a pocket).

Ideally, the sensors would have a wireless connection to the main logic unit or to the Android device.

My first idea was to connect the sensors to FLORA, add a BlueTooth module to FLORA such that FLORA communicates with the Android device directly. But AFAIR there is no good-enough support for BlueTooth on FLORA.

Are there any other ways to transfer data from sensors to main logic unit or to an Android device (except BlueTooth, wires and conductive textiles) ?

Answer 1

There's always another way.

Sensors -> logic unit connection ... Ideally ... wireless

Have you considered using XBee for your sensors to logic unit connection?

• I see lots of people connect the Lilypad to an Xbee (a), rather than connect a Flora to an XBee (b).
• A few people connect a "LilyPad XBee" ( a b c ) directly to a sensor, without any other local microprocessor. (Alas, this only works with a few kinds of sensors).

I'm pretty sure you can then connect another XBee module to your IOIO Mint, so it can collect the data from all the sensors connected to the other XBee modules.

From what I've heard, most people trying to get data through XBee and into an Android device use a USB cable for a direct wired connection between the Android and the Arduino. a b

But I've also heard of a XBee-to-Bluetooth bridge (a), and something called a "Bluetooth bee", either one of which could in theory allow your IOIO Mint to send the data to the Android device wirelessly.

EDIT:

Battery life reports:

• Rob Faludi. "Arduino and XBee Battery Test Results" -- this seems to say that a single AA NiMH 2400 mAh battery connected to a 3.3 Volt step-up circuit can power an Arduino and a XBee for 4 hours without sleeping (longer if they sleep most of them time). So you should be good for the 3 hours you mention if by "small battery" you mean a AA cell or a couple of AAA NiMH 1250 mAh cells.
• David Kirwan "Arduino FIO and XBEE 2mW radio, with 110mAh battery and 2W solar panel"
• Jean-Claude Wippler. "950 days and counting"
• Jean-Claude Wippler. "JNµ battery tests"
• Jean-Claude Wippler. "One million packets"

Other wireless things that connect to Arduino, or "are" an Arduino (can be programmed with the Arduino IDE):

• Pinoccio
• Moteino
• Twine by Supermechanical
• Juniper
• Mosquino
• RFduino
• Spark Core
• miniSWARM
• Arduino Yún
• panStamp -- one person reports running a panStamp for 3 months on a single NiMH 2300mAH AA cell without recharging (a)
• DFrduino FIO

Answer 2

You could use the rfduino, a small module that is arduino compatible and has low energy bluetooth support, and directly connect to the phone.

It's based on a chip that's targeted for similar kinds of applications(healthcare/fitness).