External Bluetooth Adaptor

I dismantled the TDK USB-bluetooth adaptor and soldered its wires directly to the ix104's upper USB connector. This is perhaps the last thing someone would want to do but short of spending a lot of time constructing a connector I had no other option:

The TDK module is glued to the ix104 and is separated slightly by some spacers:

I made a simple cover for it which is secured to the ix104 using two of the underside screws (which are not visible in these pictures):

This works very well with a bluetooth GPS; e.g. the Emtac one.

I had some problems with the TDK module. Like many cheap USB devices, it doesn't contain a unique USB device ID, so each time it is plugged into a different USB port, it creates a new COM port. This obviously plays havoc with GPS moving-map software! If you simply connect the module to the one USB port as shown above, it should come up as COM5 or COM6 and that's fine. However I had earlier plugged the unit into various ports of a hub and ended up with various COM ports up to COM14. There appears to be no way in XP to remove these, although this article shows one way. Fortunately, forcing the unit to use a particular COM port seems to work fine, despite dire warnings from XP.

In my unit, com1 and com2 are mysteriously free. Com3 is mysteriously used. Com4 is used by the USB-serial adaptor which was to be used for the RIM GPRS modem but was never used in the end. Com5 is used by the Sierra 750 GPRS modem. So I forced the TDK adaptor to com6.

This picture shows the finished unit with the bluetooth adaptor at the top; later on (not shown) I rounded off the corners on the housing. Ideally, a curved cover would be a lot more compact and I will try to get something cut out of a piece of plastic pipe.

An alternative way to do BT would be a USB-BT adaptor installed internally, with a short antenna coming out through a hole drilled in the casing and glued to the outside. BT doesn't need much of an antenna to work at a short range.

There are plenty of other BT adapters; for example the D-Link one:

I have found the D-Link software to be rubbish in most of its functionality but it did work for providing a simple COM port for a GPS. However, just plugging one in as shown above is asking for it to get broken off, perhaps damaging the sole USB socket in the process.


Page last edited 22nd March 2005