Results
Our final product performed as planned with the exception of using the keyboard as our input. We did manage to obtain a pulse train output from the keyboard, but the Handyboard was unable to process the signal fast enough to decode the letters. As an alternative method for user input, we used a slider mechanism to select letters and a combination of toggle switches to move through characters within a word and initiate the plotting algorithm. This turned out to be a simple, but effective method of user input.
In terms of
the mechanical design, both the pulley mechanism for X-translation and the rack
and pinion for Y-translation provided smooth movement of the pen. The limit
switches, which were mounted on one end of the rack and on one of the frame
rails, allowed us to successfully find a home position for the plotter and base
all subsequent movements from that position.
The only implementation
issue that we encountered during testing was an initial lack of power for our
solenoid. We solved this problem by using an external 12 V power source connected
to a transistor governed by a digital output from the Handyboard.
As shown in
the video below, we accomplished our design objectives of building an X-Y plotter
capable of taking a word or phrase input by the user and plotting it on a whiteboard
surface.
If we had
the opportunity to make any additional modifications, we would probably build
a sturdier top surface that was completely level and alter the algorithm to
use the complete surface for writing. We would also make other modifications
to the algorithm such as the ability to draw different fonts and letter sizes
and include additional punctuation and numeric characters. Overall, we feel
that we accomplished our design objectives, learned about practical issues regarding
the design and construction of mechatronic systems, and had fun in the process.
If there are any questions or comments relating to our project, please contact
any of the group members.
James Finley: j-finley@northwestern.edu
Jamie Wright: j-wright6@northwestern.edu
Lenny Oberbroeckling: lennyo@northwestern.edu