Ok, so I setup my new treadmill desk. Turns out, if you walk about 0.7-1 mph, you can use a mouse and keyboard just fine. (I have a heavy logitech G502 which seems to be pretty resilient to vibrations)
So the problem is actually that my head bobbing makes it harder to look at things on my monitor. Now, one obvious solution that isn’t ready for prime time would be a head mounted display so the monitor moves with my own head motion. Until that is available, I am trying to rough out the math for motion here.
If I move the display twice as far away, the text is easier to focus on because there’s a triangle : the upper and lower points of my head motion and the 2 sight lines at those respective positions. Doubling the distance makes the angle difference smaller.
I only purchased a 32 inch display. Did I make a mistake and should I have purchased a larger display, placed farther from my body?
Say I had a display that was double the size in both dimensions at the same resolution, located twice as far away. (it would be a 65" TV I guess). Would the relative effect of head bobbing be smaller or the same?
The effect of your head bobbing is called parallax, and yes, it does decrease with increasing distance. This is in fact how the distances to stars (at least, the nearest stars) is determined, with the orbit of the Earth substituting for the head-bobbing. Getting a bigger monitor and putting it further away would indeed work (at least, to decrease the problem: It may or may not decrease it enough).
There is some angular movement of your head as well. That won’t be reduced by increasing the distance. But I suspect you’re right, that it’s primarily the positional movement that’s causing the problem, and it will be reduced by using a larger monitor further away.
32" isn’t all that big. If I were you, I’d get hold of a large-screen TV, at least 40", to experiment. Most modern LCD TVs have HDMI input and work fine as computer monitors. (Though sometimes you need to configure your PC and TV to use native resolution - by default, some graphics drivers add a blank border when connected to a TV, and some TVs remove a border and enlarge what’s left. You need to disable both of these options.)