How Craig Conley (the author of One-Letter Words: A Dictionary) does this, I do not know, but here, after less than a day’s work, are diagrams of three poemometers (based on my reference to same last night). Note that the largest measures the metrical feet (the sounds) against the surrounding silence the poem always fights against. (This one device is not calibrated finely enough to allow for dimeter, but we will do without that as necessary).

The other two poemometers measure performative force and representational truth. Even though being the more sophisticated devices, they are simpler in structure. I am not sure when Craig will have these ready for sale, but I expect it will be soon.