Profile: FMDK Technologies, Inc. specializes in custom control systems, pollution control products and passenger light rail train controls. Our speed wizard is a speedometer correction device used to correct the speedometer after increasing or decreasing tire size or gear ratio. We provide calibration services, repair, parts and Merlin services. Our Merlin II® rapper control provides fully automatic operation for rappers and other cleaning devices on all precipitators. In this a single control can be used with up to 256 rappers.