Digital stereotaxic manipulator with controlled angular displacement and fine-drive mechanism

A digital stereotaxic manipulator for animal research is provided with two enhancements. In one enhancement, rotary encoders are provided, to allow tilting of the manipulator, about vertical and/or horizontal axes, to be measured within a fraction of a degree. With assistance from software that applies sine and cosine values, orthogonal coordinates that are emitted by linear reader heads can be corrected to provide accurate orthogonal coordinates, even when an instrument has been rotated and/or tilted substantially. In a second enhancement, a "fine-drive" mechanism provides precise control over dorsal/ventral motion of an instrument. A radial gear is mounted on the main threaded shaft in the vertical arm assembly. A helical gear on a horizontal shaft is used to drive rotation of the radial gear and vertical shaft. If a 1:20 gearing ratio is provided by the helical and radial gears, this provides an operator with 20-times more precise control over vertical motion of an instrument. A detente is also provided, to enable the helical gear to pop out of position without damage, if an operator rotates the main vertical shaft before disengaging the fine-drive mechanism. A digital display device with touch-screen controls is also disclosed.