Microcontrollers do a great job for allowing the simple user to gain access to advanced electronics applications.

For one of the robots I've built, I had to find a way of connecting an Atmega8 running at 16MHz with a Windows Mobile Smartphone. The idea was that the microcontroller handles some basic sensor data and controls some motors, and the smartphone runs an advanced application that controls the robot.

So how to do it? I've tried Infrared, since the Smartphone had an infrared port, but had little success with that. No way of connecting the two via serial port, since the Smartphone only had an USB connector.

The final solution was a bluetooth radio link.

We all know that connecting an Atmega8 to a computer's serial port is easy, by using the famous MAX232 module:

Using Bluetooth was even easier, since no electrolytic capacitors were needed as in the case of the max 232:

Here's the module's datasheetfor details regarding voltage and other parameters.

The Atmega8 needed a 16MHz crystal to assure reliable UART functionality at 9600bps (to sync with the BT Module). After putting everything together, I could establish a conneciton from my Bluetooth enabled PC, to the Atmega8+BtModule, and serial port service was available and connected as COM4. Using Hyperterminal, exchanging data worked flawlessly.

See my bluetooth enabled Atmega8 as used in my latest robot, Perseus 3.

Wireless Bluetooth connectivity offers a large number of possible applications. Good thing it is so easy to use!

Radu Motisan

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