What is an antonym for pedometer?

There isn't a direct antonym for "pedometer" in the sense of a word that means the exact opposite. A pedometer measures steps, so an antonym would have to be something that measures the opposite of steps.

However, depending on the context, you might consider these options:

* Distance-measuring device: This is a broad category that could include things like a GPS tracker, a odometer (for vehicles), or a tape measure.

* Sedentary activity tracker: This would track things like sitting time or time spent lying down.

* Something that measures non-movement: This could be a heart rate monitor or a sleep tracker, which measure internal activities rather than physical movement.

Ultimately, the best "antonym" depends on the specific meaning you're trying to convey.