I'm writing a steampunk novel set 600 years into the future after WWIII sends humankind back to the stone age. Slowly, the survivors begin industrializing again, and currently have steam technology which they use to power large mechs (15 feet high). The opposing side also builds mechs, but they are equipped with computers systems and powered electronically. What could the good guys do to theoretically stop the more advanced suits without killing their own in the process? Is there some kind of gun that shoots high-powered magnets or a hand-held emp ray that can be used to halt them in their tracks? I need a targeted solution that can be deployed without affecting the electrical grid (and not dependent on it either). The steam suits are made of stainless steel and use hydraulics and a rankine steam cyclone engine. I was thinking of having the opposing mechs have their hulls made out of something like this:
“Composite metal foams (CMFs) are little-known materials that are beginning to show some big promise. Last year we saw researchers adapt these lightweight materials to stop various forms of radiation in their tracks, and now the same team has ramped things up to offer protection from something with a bit more force: an armour-piercing bullet, which was turned to dust on impact. Building on this previous work, Rabiei then set about building high-strength armor. The shield was comprised of boron carbide ceramics as the strike face, with composite metal foam (CMF) as the bullet kinetic energy absorber layer and Kevlar panels as backplates. To test its durability, Rabiei and her team took aim with a 7.62 x 63 mm M2 armor-piercing projectile, which was fired in line with the standard testing procedures established by the National Institute of Justice (NIJ). “We could stop the bullet at a total thickness of less than an inch, while the indentation on the back was less than 8 mm," Rabiei says. "To put that in context, the NIJ standard allows up to 44 mm (1.73 in) indentation in the back of an armor." https://newatlas.com/metal-foam-bullets/42731/
But would that material also protect it from a magnetic pulse attack?
EDIT: I realize that my previous description of the computer systems are throwing people off. When I said advanced I mean compared to steam tech. Not compared to modern day. Advanced for that era, which would be primitive by today's standards. Think apollo 13--only not that advanced. Scaled down enough to fit in a mech, but not powerful enough to do much.