Garmin cadence and speed sensor DSC10 bike seat tube bracket

I love my Garmin Forerunner watch which I use on my bike for GPS and heart rate logging. I bought the Garmin DSC10 cadence and speed sensor, but it won't fit to the bike with the standard mounting brackets or position. From a google search it seems to be a common problem.

I designed this bracket to mount on the bike seat tube, picking up a magnet mounted on the bike crank. This will measure cadence only. You can still get speed from the GPS data.

In addition to this bracket, you will need