pulse width modulation for a solenoid.

The programmable part can be looked after by boards like the FB (Fusion Brain; ~$70; uses a PIC/PICAXE) though I prefer uPC boards like the Arduino - eg the Duemilanove with its ATmega328 uPC for ~$40. That latter has USB interface which can power it (I think the FB also) and being a uPC, it isn't as restricted as a PIC. There is a plethora of free applications & software for the Arduinos (its a public-domain based project). But both require programming nouse else the ability to modify suitable programs. Many reckon PICs are far simpler than uPCs, but I found the PICs too complex else limited & decided to re-learn the ATmega commands intead (I have previous programming experience albeit in Assembler. Using higher languages (like C++ etc) is far more common and should be simpler (as well as transportable between devices assuming feature compatibility, redefined addresses/register location etc, and suitable compilers. (Sorry, that's a bit too tech but its an extension of programming which is not an uncommon skill these days.) And both require the added interfacing, though that should be minimal. Both have onboad ADCs (analog to digital converters) so inputs should be simple (resistive dividers etc) and outputs into MOSFETs etc. Both feature PWM outputs. But having decided on a platform (FB or Arduino) I'd expect that you'd fine coding (programs) to do what you want - eg, read a value; use a look-up table to modify it; send that to the PWM and output it to the solenoid driver. But if you find you have simple linear transformations (duty-cycle is proportional to a straight-line input), then simpler 555 circuits etc will do. No more buts.