Twitchy Shoulder Blade
This gadget is responsible for the most prolonged muscle spasms I've had since I wrecked my back in a car accident 10 years ago.
The Spectronic 20D+ is a spectrophotometer, a single beam one. It uses light to triangulate the concentration of a species in solution. In particular, colored solutions. As such, I have to use a knob to adjust the wavelength of light being sent through the solution. This is harder than it sounds. Dialing a knob over the ultraviolet/visible light spectrum takes a while, and it involves much fine motor control to get the right wavelength each time. It may have a digital display, but the actual measurement is all in the wrist. And shoulder, if you sit at my desk. I think I'll be needing a massage after all this is done with.