I'm interested in controlling the direction of a DC Motor but not the speed. I'm ok with either full throttle or dead stop. I'm trying to reduce my cost since I am controlling 3 motors from 1 uC, and the motors are medium power (12V stall @ 9A). The minimum cost I can find to control a DC motor with that power runs about $10 from Cytron.
Is it feasible to simply use power MOSFETs to create an h-bridge? Will I actually reduce my costs, or will it be more cost effective to use the $10 (x3) motor driver? I'm new to motors, and I'm assuming there will need to be other hardware besides MOSFETs.
Or are there other ways of controlling the direction of the motors that might be a cheaper yet effective solution from a uC?
A single MOSFET is fine to turn a motor or other load on and off. For direction control by reversed power polarity an H-bridge is required and I think that you should buy the drivers from a reliable provider. Have a look at a H-bridge circuit diagram and find out yourself whether you can build such a thing yourself, taking into account several signs of the magic smoke