Archive for November, 2011

ANT+ Between MSP430 (also Arduino) and Android

November 27, 2011 33 comments

ANT+ what?

ant+ logoSmartphones are equipped with dizzying array of wireless communication capabilities.   Some of these features just go totally unnoticed. One such wireless communication protocol is called ANT+.

A friend of mine wanted to make a working prototype of an idea he had using ANT+ technology. While there are other mcu’s (read atmega/arduino) already had some libraries and code written for communicating against ANT+, it wasn’t enough for me.

  • Most of the existing code only worked as a slave, where it just tried to receive data sent by Garmin Heart Strap.
  • This slave implementation was only on either arduino or PC (python and C)

What I was more interested in was to leverage the ANT+ radio to not just receive data, but also send data. I wanted the mcu to interact with the world and use ANT+ to transmit data to my cellphone, for example. I couldn’t find any suitable implementations, and figured msp430 needs to have more “hacks” to add to its list.

So here goes. I bought two different Sparkfun products for ANT+. Both TI and Nordic has chips with ANT+ capabilities. The Sparkfun ones use nRF24AP1, and comes in 2 varieties.

I used the lesser chip that comes with the Launchpad to drive the ANT+ breakout as the master node. The usb stick will serve as the slave and used as debugging tool. Once the initialization hand shakes and data transmission is sorted out, I can test on the Android platform.

As of this writing, only Sony Ericsson makes phones with chips that can talk ANT+. I found Xperia X8 to be a good low-end unlocked Android phone just for general purpose hacking, with the full ANT+ capabilities onboard. In order to enable ANT+ wireless, you need to download these apps:

Here’s the video of my test setup running.
And all the relevant source code and documentation is hosted on github:

Read more…

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