NO CR2032s WERE HARMED DURING THE FILMING OF THIS EPISODE. THE TL431 GOT SICK AND SOMEBODY LOST A CAPACITOR BUT THAT'S ABOUT IT.

I built a configurable cr2032 replacement for development. It has 2 voltage modes: 3.0V and 2.75V, and 2 internal resistance modes: 20Ω and 40Ω. There's a current measuring jumper, and a connector for measuring the voltage across the "internal resistance".
The schematic can be found here.