Here you can see the twin 20k slide potentiometers used to monitor wrist position. Originally, one was going to provide an analog signal to the Arduino to control the pitch of the speaker, while the other was connected in series with the 4 AAs and 6 LEDs. However, the resulting fading effect on the LEDs was extremely biased, as the resistance was too great to see any light until the wrist was fully flexed. I had organized this setup to limit how many wires needed to access the Arduino, but once I removed the USB cable, I was no longer restricted to 4 connections running the length of the arm.
The end result had both the LEDs and the speaker output controlled by one potentiometer, but both were necessary to physically guide the lever back and forth.