I have Trek Emonda SL5 Disk 2022 and I'm considering buying Bontrager DuoTrap S. I use my Garmin Fenix 6 watch as a bike computer and I mount it on the cockpit. Can I pair it with my Garmin Fenix 6 with the DuoTrap sensor? Will I see real-time data like wattage on my watch?
For readers who don't know: Trek has dedicated conformal mount points on many of their bikes for their proprietary DuoTrap speed and cadence sensor. In the absence of this, you would have to ziptie a speed/cadence sensor to the chainstay, or rely on your typically less-accurate GPS speed (i.e. tell your head unit to use GPS to estimate speed). One thing to note is that the OP asked about wattage. The DuoTrap only measures speed and cadence, not power.
DuoTrap is proprietary to Trek bikes. However, it transmits data using the ANT+ and BlueTooth Smart protocols, which are open protocols and are used by almost all modern cycling computers. It would be a very strange decision to use some sort of proprietary protocol to limit the rider's choice of head unit. In any case, Bontrager doesn't make head units, so Trek/Bontrager (same corporate ownership) has zero incentive to do this anyway.
Sports watches like the Garmin Fenix 6 typically have Bluetooth receivers, and often ANT+ receivers also. They will typically have some sort of cycling sensor profile. If they have one, it is almost certain to accept any type of cycling sensor, so you'd just have to pair the sensor to the watch.
For historical info: I believe that Powertap hubs and SRM power meters may have had proprietary head units in their early days. Those started out as wired units, so no transmission protocol was relevant. At the time, wireless technology was less advanced and the ANT+ protocol may have been developed after SRM launched its product.
According to this site DuoTrap S supports Garmin Fenix 6:
However DuoTrap S will measure only speed and cadence (no wattage).
Update May 16 2022: I have acquired one. After fiddling a bit with the installation and pairing I can confirm that it works.
An important detail when pairing the sensor to Garmin Fenix 6 is to choose
Sensors & Accessories -> Add New -> Speed/Cadence. After adding it the sensor should appear as
Spd/Cad in the list of sensors.
When I initially used the
Search All Sensors option it was detected and added as just a Cadence sensor and was not reporting data to the Garmin Fenix 6.