For each successive sprint, we added an additional component of our mechanical system. We started with the punching mechanism, and then moved on to the gantry, and the roller. Each component added a degree of freedom to our project.
In sprint 4, our team was very focused on all the little finishes needed for demo day. We wanted to get off of the bulky desktop power supply for powering the solenoid, improve the aesthetics of our box, and resolve a problem with the braille cells printing diagonally over time.
We purchased a 19.5 V laptop power supply and transferred the solenoid circuit from a breadboard to protoboard. We then stripped the laptop charger, separated power and ground, and attached pins so it could be connected to the protoboard.
To resolve the diagonal printing, we modified the transitional movement of the gantry to get rid of an extra transition that was skewing the print, which can be seen in the video below.
Finally, we worked on improving aesthetics. We replaced the rollers from the pencil rollers with a fresh pair of pencil grips and removed the electrical tape that had been holding the previous pair. We rastered our team name into the protective acrylic plate above the printer.