electronic pantograph - for use with a computer

electronic pantograph elektor june 1985 A pantograph is an instrument with jointed rods for copying plans, drawings, etc., on any scale; the electronic version described in this article does so in graphics form on the monitor of a computer. It may also be used for drawing or writing direct onto the screen. The instrument is connected to two analogue to digital (AID) converters, which translate the coordinates into digital signals. for use with a computer electronic pantograph Figure 1. This diagram illustrates the operation of the pantograph. Co- ordinates xi, yi are calculated from R and angles a and (3 according to the following formulas. xt =R[cosV—a)—cosa] yt =R[sin(fi—al+sinal At the point of origin in figure 1 is a potentiometer to the spindle of which one of the rods of the pantograph, of length R, is connected. When that rod is moved, the potentiometer setting is changed. If the potentiometer is positioned such that it is at zero when the rod coincides with the negat...