This device has one major fault; the standard analog Polaris transmitter is completely omitted. This means it will not work with existing Polaris receivers or other compatible equipment such as treadmills. This means yet another piece of gear to sort through depending on the workout you want. Headed to gym, then get the standard one, headed for a run then take the bluetooth one. I strongly suspect that including the standard analog transmitter would have added an undetectable weight and reduced battery life from 150 hours to 145. But it would have made it so much more useful to have both signals simultaneously broadcast.
The bluetooth is everything we come to expect. It will not work at all through the human body. It will work 20 feet across the room, but not if you put the phone in your pants pocket. Outdoors away from radio reflective surfaces, if the phone is anywhere but in a close line of sight to the chest strap such as in your hand on in an arm strap then it will not work.
Bluetooth requires a connection-oriented design, the phone 'talks' back and forth with the heart rate monitor. Loose the connection even briefly and you have to manually reset it. Most other wireless heartrate monitors are connection-less, they simply broadcast and do not have to spend battery power caring if any devices are listening. Thus the battery life is a dismal 150 hours. The same battery in a standard transmitter gets about triple that.
Perhaps a better implementation for getting heart rate data into a smartphone would be an attachment for the phone (similar to what Square does with their credit card readers) or a specialized SD card which can pickup the standard Polaris heartrate monitor signals.
A quick primer on why bluetooth is an ill suited technology for this kind of use: The radio frequency it uses is 2.4 Ghz. Indoors this will reflect off nearly anything metal bigger than about 5 inches across. Thus indoors bluetooth doesn't need perfect line of sight to work. Microwave ovens use 2.4Ghz because water is nearly opaque at that frequency and all the energy gets turned into heat inside the water. The human body then is basically opaque to bluetooth devices. The output power is on the order of a milliWatt, so the range is limited to about 20 feet in the best case, put anything in the way such as your own body, and the signal strength and range is reduced. Outdoors there are usually few metal reflectors within 10 ft, so a direct line of sight is required. Ant+ heart rate monitors also use the 2.4GHz frequency.
Old style heartrate monitors use a frequency which passes right through the human body.
The bluetooth connection on this device is implemented as a pair of serial ports. This means only Android phones 2.0 and higher can use this heartrate monitor. For some reason this isn't printed in text anywhere in the product description or on the Worksmart labs website. This is probably a non-issue since virtually all Android phones in use today are 2.0 or greater
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