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Engineering using Spreadsheets

3 Wheel Spirograph: How it works

Description
How it works








The Farris equations used for generating a 3 wheel spirograph are:

x(t)  = Rad1*COS(2*PI()*Speed1*t+Phase1)
        +Rad2*COS(2*PI()*Speed2*t+Phase2)
        +Rad3*COS(2*PI()*Speed3*t+Phase3)

y(t) = Rad1*SIN(2*PI()*Speed1*t+Phase1)
       +Rad2*SIN(2*PI()*Speed2*t+Phase2)
       +Rad3*SIN(2*PI()*Speed3*t+Phase3)

Essentially, this tool is a customisation of the Parametric Function Plotter tool, for plotting the above equations. As the formuale are fixed, this tool does not use Data Tables but execute them in memory through Defined Formulae. x(t) and y(t) are calculated for 1000 points between t=0 and t=2*PI(). The values of t are generated by the same means as in the Bode Plot tool, see the formula used for calculation of w in how the Bode Plot works.