help designing a circuit

so im putting together a 3 "cylinder" selenoid motor. it will have 3 selenoids acting as "pistons" the selenoids are 120 degrees apart from eachother on the crankshaft. the next step is designing the triggering circuitry. the selenoids operate on 24VDC and only draw a few hundred mA. im looking for input on the circuitry. i would like to make it adjustable as far as how long each coil is turned on when it is triggered. what would be the best triggering method? there are reed switches, hall effect sensors, and optical detectors. any help would be appreciated!

Will the motor be reversible? Controllable speed?
A stepper-motor or BLDC motor control IC may be the answer.

it wont be reversible but yes, i would like controllable speed. could you recommend a circuit?

I can't recommend a particular IC, but from its datasheet the MC33033 looks like one possibility, using external NFETs to drive the solenoids and using Hall switches or opto-sensors to detect shaft angle.