Wireless Technology/Frequency of Cordless Cyclocomputers and Heart Rate Monitors???????????

[NYC Doc]

What RF regime do bicycle computers and heart rate monitors use?


Previously, I owned a relatively expensive ($300) Polar S-710, which did not
appear to suffer from any interference in the year or so that I owned it.
The $45 Vetta RT 88 that I recently purchased and quickly returned was
severely impacted by electronic devices including personal computers and
cell phones. The latter caused a problem becuase I mount my cell phone to
my handlebar. When I called tech support, the representative said this is
a know issue. When I told him this behavior was never exhibited by my
Polar, the rep responded with "that is why it costs $300".

Other people have mentioned that it is these computers are affected by
underground electrical equipment. Here in Manhattan, they could be
referring to subway transformers, but I can't be certain.

As I understand, the Polar models are coded and the cheaper heart rate
monitors (and bicycle computers) are not. Any idea what the difference is?

 

[Frank Raffaeli]

What RF regime do bicycle computers and heart rate monitors use?


Previously, I owned a relatively expensive ($300) Polar S-710, which did not
appear to suffer from any interference in the year or so that I owned it.
The $45 Vetta RT 88 that I recently purchased and quickly returned was
severely impacted by electronic devices including personal computers and
cell phones. The latter caused a problem becuase I mount my cell phone to
my handlebar. When I called tech support, the representative said this is
a know issue. When I told him this behavior was never exhibited by my
Polar, the rep responded with "that is why it costs $300".

Other people have mentioned that it is these computers are affected by
underground electrical equipment. Here in Manhattan, they could be
referring to subway transformers, but I can't be certain.

As I understand, the Polar models are coded and the cheaper heart rate
monitors (and bicycle computers) are not. Any idea what the difference is?

There is no regime. There is good and bad design, and everything
in-between. I believe most companies would develop other projects
given the choice of where to spend the engineering funds.

I don't know much about the device's features, but I can guess it's a
trip computer with an LCD display, battery and microprocessor. It also
has a remote sensor attached to a wheel that transmits data (speed?)
back to the receiver. The microprocessor then converts this to
distance, etc. Am I close?

Approaching the optimum design takes longer. It might consist of a
simple transmitter (2-transistors) with an L-C tuned tank. An
inexpensive microprocessor (~0.28) might be needed. A tiny magnet on
the wheel could sense speed and also power the transmitter.

The receiver would be a bit more sophisticated, but the microprocessor
could be used to help process the receive signal. (more than simple
decoding) We pay ~0.65 for such a controller with A/D inputs.

If this device sold a few hundred per month, with case, we could build
it in the U.S. for about $5-$7 and sell it for $9-$13. (manufacturer's
selling price.) Then there is distrubution ($16-$22) stocking, and
sales (~$45)

Is there a demmand for this type of device? I'm clueless about
markets. I'll look at the Polar and Vetta units. My hunch is that no
unit would sell without a brand name.

Frank Raffaeli
http://www.aomwireless.com/

 

[Frank Raffaeli]

What RF regime do bicycle computers and heart rate monitors use?


Previously, I owned a relatively expensive ($300) Polar S-710, which did not
appear to suffer from any interference in the year or so that I owned it.
The $45 Vetta RT 88 that I recently purchased and quickly returned was
severely impacted by electronic devices including personal computers and
cell phones. The latter caused a problem becuase I mount my cell phone to
my handlebar. When I called tech support, the representative said this is
a know issue. When I told him this behavior was never exhibited by my
Polar, the rep responded with "that is why it costs $300".

Other people have mentioned that it is these computers are affected by
underground electrical equipment. Here in Manhattan, they could be
referring to subway transformers, but I can't be certain.

As I understand, the Polar models are coded and the cheaper heart rate
monitors (and bicycle computers) are not. Any idea what the difference is?

After I read the manual for the RT88:
http://www.vetta.com/NewPDF/RTSeries/RT_English.pdf

I wondered: what are the advantages to making this unit wireless?

Frank Raffaeli
http://www.aomwireless.com/