After David rekindled my interest in geotagging blog posts with Google Map integration, and Dave's photo tracking experiences convinced me to revisit geotagging photos, I posted An ABC of geotagging photos on the Mac. In that article I considered questions relevant to selecting an automatic geo-location system, naming most of the few Mac-compatible devices available. I recently purchased a data logger to overcome the pain of manual photo geotagging and dispense with the hassle of a DIY solution.
There's lots to like about the Holux M-241 on paper—despite some concerns as noted in Richard's detailed review. The device's appetite for AA batteries will be the decider for some people. We usually pack a recharger for my wife's noise-cancelling headphones when we travel anyway, so using rechargeables is no big deal. In fact I prefer something I know I can replace, as I don't want to end up with yet another working but unusable device due to a tired non-replaceable lithium battery (like my 1st iPod, Palm, mobile phone).
The Qstarz BT-Q1000P was my original choice and could be obtained in the UK via eBay, but at nearly twice the price of the Holux. I have to say I like having a built-in display on the logger very much. This gives access to the M-241's 6 operating modes:
- Track Log Mode (the default; use Start and Stop (Enter button) to begin/ end a track logging session);
- Time Mode (useful display of UTC time for camera sync; can specify UTC offset for your time zone);
- Show Position Mode (displays current GPS coordinates; record waypoints using the Enter button);
- Show Speed & Altitude Mode (speed, altitude, and heading);
- Measure Distance Mode (recording current distance "as the crow flies" from a point of origin—not a pedometer);
- Setting Mode (change settings, erase logs, etc.)
Bluetooth paring to the Mac
With the Mac's Bluetooth turned on (I keep it off for security) and the Holux likewise turned on, choose Set up Bluetooth Device from the Bluetooth menu (or click the + in System Preferences > Bluetooth if Bluetooth isn't shown in your menu bar). Run through the Assistant entering the specific passkey 0000 when prompted. On successful pairing the Holux should be listed in System Preferences > Bluetooth along with any other Bluetooth devices you may be using:
Bluetooth pairing the Holux with the Mac
Setting up BT747 on the Mac
The open source BT747 Java software provides a way to access, download and convert track logs, as well as configure device settings for several data loggers. This ugly duckling can be used in conjunction with USB to UART Bridge Virtual COM Port drivers that can be downloaded for OS X (Universal Binary) for USB connections (instructions). It can also facilitate connection with your Mac over Bluetooth—without the need for installing drivers.
Thanks to Jan's excellent tutorial, getting the Holux to work with your Mac via Bluetooth is not too challenging. For my own record I'll briefly paraphrase the essential steps here (after pairing):
- Download the latest release of BT747 here, rename the expanded folder to "GPS" and move it into /Applications;
- Replace the file bt747_macosX.command within /Applications/GPS/ with the edited version below;
Download a pre-edited bt747_macosX.command script here.
- Rename the directory rxtx-... within /Applications/GPS/ to rxtx;
- Open a Terminal window and run the following command, entering your root password when prompted;
sudo mkdir /var/lock && sudo chmod 777 /var/lock - Open bt747_macosX.command in Terminal and click the BLUETOOTH button in the Con tab of the waba.applet.Applet that opens;
- In the applet's File tab change Output dir: to /Applications/GPS then click the Apply&Set the above values button.
If you require more details please refer to Jan's tutorial.
Retrieving and converting logs using BT747
If BT747 is not already running, open bt747_macosX.command in Terminal and click the BLUETOOTH button in the Con tab of the waba.applet.Applet that opens. A successful connection is confirmed by the presence of the Bluetooth icon on the Holux display, a "connected" Bluetooth icon in your Mac menu bar (if Bluetooth status is shown), and the presence of data in the Con tab (note that the software should automatically jump to the Log tab after connection):
Bluetooth port closed (left) and open (right) using BT747
In the Log tab, clickGet Log to begin the download via Bluetooth:
Downloading the track log using BT747
This will download a binary file to /Applications/GPS/ called BT747log.bin. Once this is done you can convert the file into usable formats from within the applet. For example:
- Click the To KML button to produce a GPSDATA-YYYYMMDD.kml file for viewing your tracks in Google Earth;
- Click the To GPX button to produce a GPSDATA-YYYYMMDD.gpx file for use in geotagging applications.
Click thumbnail to enlarge image
Matching GPX tracks to NEF images in GPSPhotoLinker
You can download logs from the Holux via Bluetooth even with no battery in the device, providing it is drawing power from your Mac over USB.
Using the Holux with Mac GPS software
As well as functioning as an independent device, the Holux can provide GPS data to other devices via Bluetooth or USB (confusingly referred to as "GPS mouse" mode). For example, the adware app GPSUtility could be used on MacBook to plot your current position:
Using the Holux with Windows GPS software
This was my introduction to the supplied Windows software when connecting via USB (it refused to connect via Bluetooth):
A Mini GPS Viewer is also available for download (the only viable option, since the supplied mini CD is incompatible with trayless drives). However, despite successful pairing and connection via Bluetooth the utility would not report a position (I wasn't able to get a USB connection to Mini GPS Viewer, despite getting the Holux Logger Utility to work intermittently over USB):
How typically Windows: the unsupported Mac solutions prove more reliable!
Using the Holux with Palm GPS software
Pairing the M-241 with my Palm T3 and using it with GeoNiche was not at all difficult:
Using the Holux with Windows Mobile GPS software
I easily paired the M-241 with my Dell Axim X50v and TomTom was able to use it for in-car navigation:
I didn't bother installing the downloadable Mini GPS Viewer for PPC.
Comparison to an in-car system
Using this solution I was able to directly compare the track log made by the Holux to that of one created using my 4 year old Navman in-car navigation GPS unit (with a 12-channel SiRF chipset). The 4.4km test route I walked used only pavements and paths and thus any deviation could be clearly identified in Google Earth.
Click thumbnail to enlarge image
Navman (red), Holux (green and blue)
The track recorded with the Navman (red) was near perfect. A recording made at the same time using the Holux (green) was exceptionally disappointing, especially after a seemingly accurate performance in the Peak District. However, at the end of the route the low battery symbol was flasing, and it may be this—or potentially interference—that caused the Holux to perform so poorly.
I walked the route again this time using only the Holux (with a fresh battery) and the track was much improved, almost overlapping that of the previous day made by the Navman. I think we can lay to rest the myth, however, that newer units will always out-perform older models designed primarily for in-car use. It would have been most interesting to see how the Qstarz BT1000P compared using the same route as above.
I can provide no objective figures, but the Holux (with 1 AA battery) dose have a lot less stamina than the Navman (with 3 AAA batteries). I have 2100mAh rechargeables lined up to try so we'll see how those go.
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Interesting how the Holux matched the Navman on the second time around.
I didn't think battery power level would harm the performance of a GPS unit (digital yes/no thing), but maybe it does? Or just (slightly) different atmospheric conditions?
Any difference in the positioning of the Holux? Antenna up, clear view of sky?
Certainly the second results for the Holux are encouraging and show it can record a track accurately.
You're probably right about the battery not being the cause icerabbit; the symbol was only flashing... it hadn't died. As for atmospheric conditions they were the same for the Navman which did well. I really can't explain why it was so off one day and fine the next.
In both cases I wore it with the correct side up on a lanyard and although the route includes some sparse tree cover there were no tall buildings to obstruct signals. Heck, the Holux can even get a signal inside sitting at my office desk—unlike the Navman.
Considering the typically poor Windows software, I guess the most likely explanation is great hardware let down by poor programming i.e. firmware bugs. A bug is the only reasonable explanation for inconsistency when other conditions are unchanged, isn't it?
Even the bad track is still better than manual geotagging.
Thanks for doing all this research Bruce, it's going to make my life easier when I come to make a decision on a purchase.
I suppose in the situations I generally find myself wanting to record the position of a photograph, the accuracy of the Holux is not going to be a problem.
Maybe not, but the battery life will be. I was severely disappointed during our 6 days in Prague: I went through 5 batteries—one per day I used it, 2 of those high-capacity 2100mAh rechargeables. I'm not even sure you can count on getting 3 hours of run time (a typical walk in the Peaks for us). Now it is possible that the batteries I took were too old (having sat in a draw at least 18 months), but the recharageables were freshly topped up and certainly should have had plenty of cycles remaining. I think I will buy some new Energizers before making a final judgement, but anyone reading this should be warned that battery life is much more of an issue than I anticipated. With the Holux in the pocket of my camera bag I had no way of knowing when it died; it definitely went from showing full charge to dead after just 2 hours on one occasion!
hmm.. methinks I shall await an iPhone integrated solution.
Thanks for the update Bruce.
It sounds like it might be a combination of batteries and a power hungry Holux.
I am not confident any more that the Energizer and other A brand rechargeable are as great / last as long as they used to be / to do. Plus the lack of memory effect doesn't help with storage necessarily.
I've got some 1 year old Li-ION bricks for pro tools that you're supposed to store charged and keep cool (basement, closet) when not in use for a prolonged time and I just took them out of storage (4 months) and their indicator lights were flashing empty (0/4). So much for holding power. At least these have a lifetime replacement warranty.
Last year I sent a batch of Energizer 2500 mAh back under warranty. They had been marked (permanent marker colored rim per set of 4 (helps to keep track of batteries and separate out different mAh types)) used for a couple months exclusively on a digital camera with mild use, where the camera was used a couple of times a week for a few shots. Charged exclusively with their charger without leaving them plugged in for days at a time. The things wouldn't hold a charge for days without using them. Charge during the week. Pick up the camera on the weekend and a x number of shots later the camera is out of juice.
The other thing we have noticed along that, we think, is that the AA 1500 - 1850 range held up for more months that the newer 2100 and certainly the 2500 series do. We've used the older kind extensively with cameras and anything that uses AA batteries on car trips, and the batteries certainly seemed to hold a good charge for probably a hundred charge cycles and thus lasted several years. Now, the newer new 2000+ ones start flashing in the charger = kaput after a couple dozen cycles.
Of course one can argue that different cameras have different power needs, the chargers changed from whole day to 8 - 4 - 1 - 1/2 hours. We're happiest with the 2100 mAh and 1 hour and 1/2 hour chargers. Which are no longer available :)
Anyway. Didn't hear back any details on that from Energizer (not that I expected it). They were going to analyze my batteries in the lab and gave me two discount coupons for new batteries.
I'm still using the new 2500s with our 'old' 1/2 hour charger that came with 2100s. I'm thinking the 'new' charger was to blame. Or just a fluke where they forgot to put the right mix in a batch of batteries. Who knows ? :)
Another battery update. I took out the Engerizer in my Holux: it had Jul 1998 written on the side. Opps! So in went a brand new Engerizer Ultimate ("Use by 2013"); I turned on the logger and left it to die:
First time stamp: 9 May 2008 11:34:14
Last time stamp: 10 May 2008 01:00:50
That's 9841 track points consuming 7% of available storage, covering approx. 13.5h and costing £1.25 (not including environmental damage!). That's more like it.
I can only assume my lightly-used Uniross 2100mAh rechargeables are either rubbish, or that they too deteriorate after a few years.