Holux M-241 Bluetooth USB GPS Receiver Review

GPS capability is built into pretty much everything these days from phones to tablets, but one portable device that’s so far missed out is the humble laptop. The need for a laptop in a car is decreasing, as personally I find tablets more convenient, but sometimes you’ll need a moving-map on a laptop. That means a GPS receiver of some sort, and these days Bluetooth is reliable and easy enough to set up. And that’s why I’ve got a Holux M-241 GPS Mouse/Datalogger at a cost of AU$109.

The M-241 fufils several functions in one tiny packet, but I’m interested it in as a source of NMEA data for a GPS moving map, and as a datalogger to record tracks. The M-241 is a high-sensitivity Bluetooth GPSR powered by a single AA battery, yet at the same time you can connect a second computer via USB so it can provide two NMEA outputs at the same time. The USB input also provides power, but the AA will run the unit for about 12 hours anyway. The M-241 is also a datalogger, with several options to set the frequency of trackpoints, for example by distance or by time. Even if you set it to one second with 100,000 points that’s 28 hours of continuous tracking, so well more than a day’s drive although given where we’re at with flash memory I wouldn’t mind seeing an extra couple of zeroes on that number. The tracklog can be set to stop when full or overwrite.

Setting up Oziexplorer for either Bluetooth or USB use is easy. For Bluetooth just scan for the device, your computer finds it, creates a virtual serial (COM) port and you set Ozi to use that at 4800baud as a NMEA Only GPSR. For the USB device install the supplied drivers which also create a virtual serial port, set Ozi to use that at 384,000baud, again with a NMEA Only GPSR.

The M-241 also boats a small but functional LCD display with two keys to change settings. While it’s no handheld bush unit, you can see your lat/long location, satellite lock, time, speed, direction and there’s basic distance measuring facilities too. Several settings can be changed such as the tracklog frequency. However, you’ve probably already got a smartphone with a GPSR and there’s software which does all that and more, better. Still, it’s useful to have the facility.

Now on to the drawbacks. While the M-241 is tiny at 32 X 30 X 75mm and weighs only 39g plus battery, it is oddly shaped. It should be a practical rectangle you can glue or Velcro to something, but instead it’s all rounded. Then there’s the orientation – the unit says you should mount it vertically, yet then the base is inaccessible and that’s where the USB cable goes and it’s also the battery compartment door. And the display is then at right angles to the eye. It would also be sensible to have logging on by default, rather than requiring a manual start. Getting data off the device should be easier too – it would be nice for it just to appear as a USB disk, but instead you need to install special software just to pull the log off and convert to a format like Google’s KML or the standard GPX. And finally, I don’t like the bright yellow for in-car use.

To sum up the M-241 – the GPS receiver function works very well, the track logging sensivity is excellent and it’s good it can work simulatnously as a Bluetooth and USB NMEA output device. The extra features such as the distance measuring and speed readout are not a bad idea, and overall if you want a cheap but useful Bluetooth received I think this one would be pretty high on the list. Bear in mind that there are apps for at least Android devices which broadcast NMEA data over Bluetooth – see more here http://www.4wdhandbook.com/rmp/blog/best-android-apps-offroad-travel

Related links

• Tablet offroad navigation - Android Honeycomb, Oziexplorer and more