Connecting a Telescope to Planetarium via Bluetooth

(Connecting via serial port is described here)

To connect the Telescope via Bluetooth you need the following:

• Bluetooth capable Palm device
• Bluetooth to serial converter
• Bluetooth telescope driver

Bluetooth capable Palm device

The following devices are natively Bluetooth capable:

• Palm Tungsten T
• Palm Tungsten T2
• Palm Tungsten T3
• Palm Tungsten T5
• Palm Zire 72
• Sony Clié PEG-NZ90
• Sony Clié PEG-UX50
• Sony Clié PEG-UX40
• TapWave Zodiac
• TapWave Zodiac 2
• Treo 650

Devices runnung PalmOS 4 can add a Bluetooth SD card. Google for Palm Solutions Group Bluetooth SD Card to get information or find a store. Also check ebay!

At the time of writing (November 2004) no Bluetooth add-on solution for PalmOS 5 is known to the author.

Check http://www.palm.com/bluetooth for up-to date information.

Bluetooth to serial converter

I tested the setup with the AIRcable. It is a bit tricky to get running, so please read all of their website if you have problems.

There are other Bluetooth to serial converters around, all a bit more expensive. I have not yet tested it with them (and they may be tricky to configure just as well).

• Power: The newer models (those with the blue LED and 4 dip switches) can use 5-15 Volts external power. (Attention: The older models used 4-10 Volts!) So this would be just fine for those who have 12V ready from the telescope or from a car battery. You can connect the power either via a power plug on the side of the device or between serial pins 9 and 5.
  
• RTS/CTS: If you have an older model (with the red LED and 3 dip switches), a bridge is required between RTS and CTS (pins 7 and 8). Otherwise the AIRcable does not send characters to the Palm. The newer models do not require that any more, but you need to set the new switch labelled "Hardware handshake" to the off position.
• Configuration: To configure the AIRcable, you connect it to the PC running HyperTerm and send it commands via the keyboard. Set the baud rate in HyperTerm to 115200. Check the setup by typing <control-A> H <enter>. Note the capital H. The module should respond by writing some status information. Now type <control-A> A3 <enter> to bring it into Service-Slave Mode. The module should respond with "OK". To avoid having to type the PIN code repeatedly also disable authentication with <control-A> PD <enter>. Check http://www.aircable.net/AIRcable/CLI.html for further details.
• Don't forget to set the baud rate to 9600 for the telescope with the mini dip switches.

Bluetooth telescope driver

The following telescope drivers are available:

Download the appropriate file and install it on your Palm.

Here is some information from a user who tested various Meade and Celestron telescope configurations.

Usage

Set up your telescope, align it and switch on the Bluetooth to serial converter.

Start Planetarium. If the telescope driver is installed properly, the telescope button shows up in the sky view tool bar. Tapping this button opens a popup menu with the available functions.

• Query Position - Asks the telescope where it is pointing at and displays a symbol in the sky map.
• Set position - Only available if you have a Goto telescope and if you have selected an object in the sky map. Commands the telescope to that object.

At the first time you issue a command the program tries to establish connection via Bluetooth. You are prompted to select a nearby Bluetooth device. Select your Bluetooth to serial converter. You might have to enter the PIN code. Once connection is established, the commands are sent to the telescope. The Bluetooth link is held active for subsequent commands.

If the Palm is switched off either manually or automatically the Bluetooth connection is dropped and has to be reestablished when you switch the Palm on again and want to send another command. The program will automatically try to reconnect to the device you selected previously. If the Bluetooth-serial converter is switched off, connection is lost and you will have to reenter the PIN code to establish it again (unless you have configured it not to require authenitfication).

If you find the auto-off switching of the Palm annoying you can try out this little program that lets you specify a longer auto-off time:
http://home.vrweb.de/~jswi/SoftPalm/AutoOff.html

Special issues with the Tungsten T3

There is a bug in the T3 that prevents the T3 from accepting a correct PIN to the Bluetooth-serial converter. It stays in the dialog and keeps asking for the PIN.

The best solution to this is to check in the manual of your Bluetooth-serial converter if it is possible to configure it not to require autihentification: The T3 won't ask you for the PIN any more.

If this is not possible, then the following procedure is necessary:

• After powering on the Bluetooth-serial converter, start the Preferences application and select Bluetooth.
• Tap "Trusted devices"
• Add the Bluetooth-serial converter to the list (or if it is already there, delete it, then re-add it)

Note: This will have to be repeated every time you switch off and on your Bluetooth-serial converter.