robfinch wrote:
find a PI-like x86 computer
As reference, a "PI-like x86" would look like the "LE-366 SBC mini board" equipped with AMD Geode LX 800.
The CPU is a AMD Geode LX 800 @ 500MHz. It's x86 compliant, able to run WindowsCE, Windows XP, and Linux. It's usually comes with installed 256 MByte of ram.
spec and info
here. It cost 180 euro when it was a new entry, now you can fine one for 20-30 euro. I have two of these boards, used as embedded SBC to control an industrial sewing machine.
Otherwise, second hand cheap Dell Pentium4 or Intel CoreDuo/Dual mini computers. 50 Euro each.
p.s.
the RDS_on of a mos transistor can be be 0.010 ohm if you choose the right device with the right polarization (1), but if you are afraid of it, you can use an mechanical device electrically operated (aka Rele') which offers an impedance close to zero (0.001 ohm ).
(1) high saturation, narrow channel, with this setup it operates as a current generator, so it has a very tiny impedance