Proposal Bot/Spring/2020
Pen Pressure Calculation
Author: Jonathan Valdez (Electronics & Controls – Hardware)
Table of Contents
Introduction
This pen pressure calculation is done using the weighted pen design which is to be used with Proposal Bots Pen Plotter. This pens pressure is measured normal to the ground in this case a table and is equivalent to the downward force known as weight.
WEIGHTED PEN DESIGN
Figure 1: Weighted Pen Design
This design utilizes two fishing weights which are to be taped to both sides of the pen to act as a solid balanced unit that produces a downward force so that the pen will be able to write a message smoothly without scribbling or ripping the paper. This downward force is known as weight and is equal to the mass of the weighted pen multiplied by gravity.
PRESSURE CALCULATION
Conclusion
This large amount of pressure is expected since the area of the tip of the pen is so small. The pressure of the weighted pen can be adjusted as needed by replacing the size of the two fishing weights. This pressure calculation was planned to be utilized to compare the limits of downward force required to not rip the paper Proposal Bot is writing on. Unfortunately, we never got to test these limits of downward force since the library closed and we did not have access to the 3D printed parts we paid for. Also we would have liked to use a digital force sensor to simulate the pressure of typical handwriting force and used that to compare it to the pen pressure calculation, this experiment would have been interesting especially since there wasn’t any data available regarding this matter online.