Monday, March 25, 2013

Fun with Garmin

From top to bottom, left to right, the Garmin strap for my heart rate monitor, the Polar replacement strap for my heart rate monitor, the medical electrode gel, the Garmin heart rate transmitter, and the Garmin Edge 300 cycle computer. The straps are oriented to show the part that sits against my skin. the two shiny patches on the Garmin strap and the two patches of slightly different texture on the Polar strap are what actually detect the electrical signal associated with a heart beat. 


Last November I purchased a Garmin Edge 500 cycle computer ($250), a cadence detector ($40), and a heart rate monitor ($40). I have been wanting a Garmin 500 for some time, but what inspired me to finally put down my money was that I needed a heart rate monitor to be able to try Phillip Maffetone's Aerobic Training Plan, and this was one way to get one. One reason I had hesitated to buy it before was the mixed reviews this device received on Amazon, reviews subsequently reinforced by my experience. Although my expensive new Garmin would occasionally loose the data from a ride, I forgave it because the heart rate monitor seemed to work reliably, and that was the main thing I needed. So, when heart rate measurements became unreliable about six weeks ago, I was most displeased.

As above, but the other side of the strap and the back of the transmitter are now shown, revealing the snaps used to connect the transmitter both mechanically and electrically to the strap.

At first I wondered if the irregularity was an irregularity of my heart. I looked into this possibility and found a condition called "exercise tachycardia" that seemed to explain what I was experiencing. (Exercise tachycardia not dangerous.) However, as the results reported by the monitor became more and more erratic, it began reporting heart rates that were simply impossible, and I concluded the monitor was malfunctioning. In the Garmin system, the detection of my heart rate requires three pieces of equipment; the Garmin Edge 500 which acts as data receiver and recorder, the data transmitter which is a separate plastic object about the size of a pack of matches, and a strap. The strap contains two electrical contacts that fit against the skin of my chest, which are held in place by the strap,  and which pick up the signals that cause my heart to beat. The transmitter is also attached to the strap. The raw data from the strap is sent to the transmitter which then wirelessly sends it to the Garmin 500. To guarantee good electrical contact between the sensors on the strap and my skin, the instructions advise to me wet the contacts with water. This is not always necessary as sweat does just fine, but sometimes it is. The transmitter connects to these sensors as well as being physically held onto the strap via two metal snaps. In principle, the problem could be with the strap, the transmitter, or the Garmin 500.

As above, but with the transmitter connected to the Polar strap.

I did further research and found that erratic heart rate reporting is a known problem with this heart rate monitor (and perhaps others.) Solutions included replacing the battery in the transmitter, replacing the strap with one from a competitor (Polar) and replacing the water used to wet the contacts with medical electrode gel. I purchased a replacement battery ($2), the Polar strap ($17), and the electrode gel ($5). I first tried putting the sensor on the Polar strap, and went from erratic results to no signal whatsoever. This continued as I replaced the battery. I never even got to testing the gel. One final suggestion I found on the Internet was to "put the battery in backwards, take it out, and put it back in the right way again." This suggestion was viciously ridiculed by other posters on the blog where it was posted, and obviously I did not try it. The one bright spot in this whole picture was the reports on the Web that Garmin is quite good about replacing transmitters that stop working. Between one thing and another, it took me a while to try to get in touch with Garmin, but when I did, I found that actually reaching a person was a challenge. Once I got in touch with an actual person, she was quite cooperative. Appropriately, she walked me through the obvious fixes, like changing the battery ("I have already done that, thanks") and then she suggested "putting the battery in backwards for a few seconds, taking it out, and putting it back in the right way" followed by re-synchronizing the Garmin 500 to the transmitter. After picking my jaw up off the floor, I agreed to try that, and all of a sudden my Garmin 500 could see the heart rate monitor again. Unfortunately, said monitor reported an impossible heart rate of 200 beats per minute. I checked my heart rate with my Panasonic blood pressure meter which confirmed a more reasonable 60 beats per minute, so although things were better, they were far from functional. I then tried the Polar strap, and and first got no signal, but after fidgeting with the connection between the strap contacts and my skin, it too reported 200 beats per minute. Finally, I applied the electrode gel to the Polar strap, and at long last, all was well. (For those paying close attention, you may have noticed that I have not confirmed that there is anything wrong with the original strap or that purchase of the Polar strap was necessary, but at this point, I am not messing with success.)

Once I got the heart rate monitor working, I went for a 17 mile bike ride with it and it functioned properly throughout the ride. So as of now, the problem is apparently fixed. We shall see how well this fix holds up.

Additional Observations and Conclusions

  1. Replacing the battery in the transmitter is a giant pain. One needs to remove the back which is held in place by four tiny screws which are difficult to replace when it comes time to put everything back together. My $40 Cats Eye cycle computer has a vastly better battery compartment. I am now using the transmitter with the original battery (which was never the problem) and the battery is supposed to last roughly four years, so perhaps this isn't a big issue. However, if this silliness of "putting the battery in backwards" needs to be done often, it becomes one.
  2. This whole system for which I paid over $300 seems very amateurish to me. The fidgeting needed to get the thing to work, the difficulty of replacing the battery, the need to invert the battery to reset the device, the fact that when used according to the instructions there is a widely observed problem with reporting of heart rates, not to mention the data loss by the Garmin Edge 500, makes this system seems more like a home made toy than a quality piece of sports equipment. If I had purchased an inexpensive no-name brand instead of the quality brand everyone recommended I would expect this, but Garmin seems to be state of the art.
  3. Garmin's system for communicating with their customers is a mess. I tried calling, and got a menu system which gave me two options, neither of which was to report a warrantee problem or to request an RMA. I assumed that this meant that I should stay on the line. Not so. If you stay on the line, it just repeats the two wrong choices over and over. At this point, I gave up and tried contacting Garmin via the email link on their website. This link is actually to a web form that requires you to select the name of the product your are asking about from a menu of possible products. Their heart rate monitor is not on the menu, so it is impossible to send an email (a deficiency their customer service rep confirmed when I finally talked to her.) I then returned to the telephone, selected the one of the two menu options that seemed less wrong, and sure enough, this eventually got me to the friendly, competent woman who solved my problem.
Although I want to like Garmin, I see this as a huge business opportunity for a competitor. As an experiment, I ordered a $40 bare bones heart rate monitor manufactured by Polar. It has no bells and whistles, it does not sync with my computer, all it does display heart rate on the included wrist watch and provide an audible alert me if my heart rate is higher or lower than values I input. My reasons for buying a second heart rate monitor were several. My wife was interested in playing with a heart rate monitor, I figured it could serve as a backup should the Garmin fail again, I was curious how well something this simple and inexpensive would work, and for reasons I will explain in a future post, it will be useful to keep a heart rate monitor next to my bed. In future posts, I will report how well the Garmin solution holds up and how it compares to the inexpensive Polar solution.

$40 Polar Heart Rate Monitor. The transmitter cannot be removed from the strap, the strap is stiffer and less comfortable, and the watch/receiver has an inexpensive, somewhat uncomfortable plastic band.



No MAF Test This Week

I am traveling this week so have not had an opportunity to perform any MAF tests in addition to what I posted last week.


1 comment:

  1. From top to bottom, left to right, the Garmin strap for my heart rate monitor, the Polar replacement strap for my heart rate monitor, the medical ... polarheartstrap.blogspot.de

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