Technology

EMPs are overrated by Hollywood, who like to show sparks and electrical arcs and robots exploding and whatnot. In reality EMPs are mainly a threat to the power grid, because they operate by inducing an electrical current in a conductor and the longer the conductor is the more powerful the induced current is. Power transmission lines are thousands of kilometers long, they'll build up fearsome currents and fry stuff plugged into them (assuming circuit breakers and fuses don't manage to protect it). But a device like this has wires a few centimeters long, so they don't pick up nearly as much as long as they're not plugged in. They're more delicate, sure, but I like my odds.

An EMP can also be shielded against by a wrapping of tinfoil, as mentioned below. As long as there aren't large gaps (no, tinfoil hats don't work) it acts as a simple farraday cage. So if you really want extra protection keep this in a metal box. Assuming its case isn't metallic to begin with.

Wrap em in foil. Boom protected. But kinda moot if there's no power.

That doesn't take much power, a solar panel or two should be more than sufficient, or you can rig something up w/ a defunct ebike (just run the motor backwards to generate electricity).

I just purchased 18 TB of surplus disks for 200 CAD, the price there doesn't seem that good to me.