Apparatus Drawings Project. Report Number 28. Versatile X-Y Projector Plotter: Developed for Undergraduate Physics Lectures at Rensselaer Polytechnic Institute

The apparatus described is a simple X-Y plotter designed to fit the slide stage of a standard 10- ×10-in. overhead projector. Graphs are drawn with felt pens on the projector's normal writing medium, a disposable plastic foil strip. A magnified image of the graph, as it is being drawn, can be projected at any size suitable for the lecture room involved. The plotter consists of two servo-balanced slide-wire potentiometers set at 90° to each other, with simple, direct-coupled amplifiers controlling the motors. Each potentiometer has a carriage, fitted with a slide-wire contact and a slotted arm, coupled to its servo-motor by a cable system. The pen, passing through both arm slots at their intersection, records all carriage movements. Both axes have a sensitivity of ca 18 v/in. over a range of 180 v that can be traversed in about 4 sec. The low-cost electronic circuits are as simple as is consistent with stability and reliability. Full information regarding construction of both mechanical and electrical systems is given.