If you fit a trip computer which reads from a magnet attached to a spoke (as most do) then fit the magnet slightly AHEAD of the crank on that side.
I have had this annoying pinging noise for a while now and thought it was a loose spoke, as it only happened at times of maximum torque - like cresting a hill. It turned out that either the wheel was flexing or, more likely the forks were, when I was pushing hardest on the pedals, and the magnet was catching the ‘reader’ attached to the fork leg. That was with the magnet randomly positioned on the wheel - coincidentally, a few degrees behind the crank. Moving the magnet has cured the problem.
I was looking at wireless computers in my local sports store. They transmit a radio signal to the computer unit, so there is no need for a wire. My idea was to keep the computer in my pocket or on a wrist band for easy reading when I was riding.
I sneakily took the instructions out of the pack to see whether the unit would work on a 36 inch wheel, and noticed a reference to the computer having to be positioned within 30 degrees of a line passing vertically up from the ‘reader’ on the forks.
Presumably the transmitter only transmits in a narrow cone like this to stop it interfering with similar computers on other cycles travelling in a group. However, it seems to me that this level of precision would be unsustaiable on a unicycle, so I guess these wireless devices probably won’t work for us.
(Incidentally, why are they called ‘wire free’ now, when ‘wireless’ means exactly the same, and was a perfectly good use of the language? Mutters darkly about things not being what they used to be…)