K8055 Bluetooth Control

Introduction to Bluetooth

Bluetooth is a wireless protocol which allows you to exchange data between all kind of portable devices. Unlike Wifi, the range of bluetooth is rather limited (for example 10 meters). So the protocol should only be used for nearby communications. Many new mobile phones, smartphones, PDAs, laptops are equipped with a bluetooth radio. For mobile phones, bluetooth can be used to exchange photos or phone numbers between 2 devices. You could also connect your bluetooth enabled phone to a wireless headset.

Since Bluetooth has a limited broadcasting range, the protocol also requires a much lower transmission power than WiFi. This is good for the the battery life and for the autonomy of your mobile device.

K8055 over bluetooth

I own a bluetooth enabled PDA device (Mio P550. I started wondering if it would be possible to use the bluetooth capabilities of this device to control the K8055 card (An interface card from Velleman).

The operating system on the P550 is Windows Mobile 5. Obviously I has to write some software that can run under this Operating System. Windows Mobile 5 supports the Compact .NET framework, so you can write your own applications in Visual Studio .NET (Visual Basic, C#, ...). At the other side I have a desktop PC with Windows XP/Vista on it.

I had to setup some sort of client/server model between the fixed PC and the PDA. The fixed PC is the server, with some kind of server program that has 2 functions. It must be able to:

Control the K8055.
Listen for incoming bluetooth connections.

The client (the PDA) must be able to:

Connect to the server using bluetooth
Send commands to the server

My solution

I found out one easy solution to solve this problem is to create a serial communication between client and server. With bluetooth you can establish a connection to another device. Once this connection is made, you can create a virtual COM port at the client side (PDA). From your programs point of view this COM port is a true hardware device. You can access the port from your software using standard software calls (in .NET you can use the "serialport" control). So you can open this virtual COM port and bluetooth will forward all transmitted data to your fixed PC. There it will be sent to the server automatically. In short you need to do these things:

Client Side

Create a client program that can connect to a certain COM port. It can be done in VB.NET with a minimal amount of programming code.
Setup the bluetooth of your PDA to make it create a virtual (outgoing) COM port.
Create a connection to the COM port. It will be forwared automatically to your server-PC.

Server Side

Create a client program with code to control the K8055 card. It will have to use the K8055 DLL files. The program also needs a serialport control that is able to accept INCOMING data.
Setup the bluetooth of your server PC to create a virtual COM port, and bind it to the incoming COM port from the PDA.

Next part: practical realisation.