Contents

Overview

Garcia mobile robot is designed ideally to work in conjuction with a host computer through a serial link.  New Garcia circuit board versions (Copyright year 2006) have added a socket for inserting a Bluetooth to serial adapter.  This adapter can provide the facility to manipulate the Garcia from a host computer using Bluetooth as a wireless serial link.  The serial headers on the Garcia between the BrainStems and the Bluetooth adapter are mutually exclusive - use of one serial port does not tie up the other one. 

Copyright location on Garcia circuit boards.

The Bluetooth serial adapter use is not constrained to creating a wireless between the Garcia's BrainStems and a host since the serial headers for the BrainStems and Bluetooth adapter are independent.  For example, one could wire another serial device, such as a scanning laser, and stream the laser data wirelessly to Bluetooth host for data collection and analysis. 

Bluetooth to Serial Network Topology

Garcia Bluetooth to Serial Hardware Topology

Bluetooth can provide a RS-232 serial port emulation through the RFCOMM protocal, which is a subset of the L2CAP protocal.  Once the Garcia Bluetooth to serial adapter is configured as a discoverable device, you can then set up a virtual serial port on a host computer. 

Garcia Bluetooth Hardware and Connections

Onboard the Garcia circuit board is 3 serial connectors based on the Acroname Serial Standard.  Each connector is labeled with it's functionality.  Included within the Garcia robot is a null modem bridging cable to connect the Bluetooth Serial port to the BrainStem GP serial port. 

Wiring the Bluetooth adapter to the GP serial port on the Garcia.

A LED indicating a successful connection will become illumniated after pairing a Bluetooth device to the Bluetooth Serial adapter inside the Garcia.  If you are having trouble communicating across a Bluetooth link, check to make sure a baudrate settings match. 

Bluetooth to Serial Adapter Information

The Bluetooth to Serial adapters built into the Garcia are shipped configured with the following settings:

• Baudrate: 38400
• Data bit: 8
• Stop bit: 1
• No Parity
• No flow control
• Bluetooth passkey: 1234

This particular configuration is set up to match the default settings of the BrainStems in the Garcia.  Depending the desired implementation intention of the Bluetooth serial link is, the baudrate settings may not be sufficient.  If the goal is to send primative commands to the Garcia, the settings should be more than adequate.  Otherwise, tight loop control across a Bluetooth connection may necessitate an increase of the baudrate settings for the Bluetooth to Serial adapter, host computer and the BrainStems inside the Garcia. 

The following outline some electrical and operational characteristics of the Bluetooth to Serial adapter inside the Garcia once configured:

• TTL UART data lines. 
• 72.4mA current consumption during Discoverable mode. 
• Range ~100m

Related Links:

Acroname Serial Interface Standard