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Advanced Laboratory / Lecture Demonstration

A computer controlled x-y plotter


The device is a modified mouse. Consisting of a separation of the system of coordinates that the mouse possesses in integrated form. Thus coordinates are moved independently by their corresponding knobs. The total movement of the cursor is plotted on the computer screen.

Support required for apparatus: An IBM compatible PC, with a mouse port, Windows 95/98

Approximate size of the apparatus: 20 cm x 15 cm x 5 cm

Does this apparatus require Electrical Power? Yes.

Is the apparatus intended for use with and overhead projector? No

Will you be present to set up your apparatus? Yes.

Equipment required to construct apparatus:

A mouse $6
Three flexible plastic tubes 0.3cm diameter; and length 10cm (x1), and 5 cm (x2).(Lengths are variable according to the mouse). A used ball point pen can provide it. $1
A couple of linear gears (1.5 cm diameter) with a 0.3 cm central hole. A fixation support (Available in toyshops) $2.5
A couple of gear (1.5 cm diameter) with a central hole enabling a 90º rotation.
A fixation support. $2.5
Two knobs attached to a vertical support, where the plastic tubes are fixed, allowing their rotation. $2
An acrylic or wooden plate measuring 20 cm x 15 cm $5 An acrylic or wooden plate measuring 20 cm x 5 cm $2
Total .................................................................................................................$21


This computer controlled x-y plotter could be used to detect early alterations in coordination of bilateral voluntary muscular movements in patients with Alzheimer´s disease. These patients manifest deficits in inter hemispheric integration of information as reported by Yamina Lamache et al [1]. Similar tests like the ones presented in that paper could be carried out using this plotter to evaluate bimanual coordination. (Preilowsky´s test)[2]. Subjects are requested to draw on an x-y plotter a line matching a sample line presented. This is done controlling the x axis by rotation of one knob with the index and thumb of one hand, and the y axis similarly with the other hand.