Planning a machine with mechanism, actuation, automation, function, and user interface.
For this week, the assignment was supposed to be a group machine build. The problem was that I did not really have a full group available for this one. It was mostly just me working through ideas with help from ChatGPT / Astra, and one helper from Fab Academy who came over while we talked through the plan.
Because of time and everything else going on, I did not fully build the machine. I want to be honest about that. What I did complete was the machine concept, the mechanism plan, the parts plan, the automation idea, and the user interface idea. I know how I would build it, but I did not get the physical machine finished during the week.
The machine idea started as a drawing machine, kind of like a pen plotter. The original plan was to take apart broken Prusa Mini 3D printers and reuse the motion parts. Then I wanted to control the machine with a Raspberry Pi 5. The machine would move a tool head in X and Y, and the tool could draw a 2D picture on a flat surface.
After thinking about it more, I started coming up with a crazier version of the same machine: instead of holding a pen, the machine could hold a cordless tattoo machine as the tool head. The motion idea would still be like a pen drawing machine, but the tool would be changed. This stayed as a concept only and was not tested on skin.
The machine concept was an XY drawing machine made from recycled 3D printer parts. I wanted to use two broken Prusa Mini 3D printers because they already had a lot of the mechanical parts I needed, including stepper motors, belts, rails, pulleys, and carriage parts.
The Raspberry Pi 5 would act as the computer/controller side. The Pi could run the software, load an image, convert the image into paths, and send movement commands to the machine.
The machine would be built on a wooden frame. I was going to design and cut the frame pieces with the laser cutter. Then I would 3D print brackets, holders, motor mounts, belt holders, and the tool holder to mount everything together.
The mechanism would be based on a simple XY gantry. One axis would move left and right, and the other axis would move forward and backward. This would let the machine move the tool head around a flat work area.
The recycled Prusa Mini parts would make this easier because the printers already have the basic motion system. I would reuse the linear rods or rails, belts, pulleys, and stepper motors instead of buying everything new.
The tool head would mount to the moving carriage. For the normal version, it would hold a marker or pen. For the concept version, the mount could be redesigned to hold a cordless tattoo machine. Again, this was only a concept idea and not something I tested on a person.
The actuation would come from stepper motors. The stepper motors would move the X and Y axes by turning belts and pulleys. This is basically how a 3D printer already moves, so reusing printer parts made sense.
I would need motor drivers to control the stepper motors. The Raspberry Pi 5 would not power the motors directly. The Pi would send control signals, and the motor drivers would handle the motor power.
For the pen version, the Z movement could be simple. It would only need to lift and lower the pen. That could be done with a small servo or a simple up/down mechanism. For the tattoo-machine concept, the tool mount would need way more safety testing and control, so that part stayed only as an idea.
The automation idea was to let the machine draw a picture automatically. The user would load a 2D image, the software would convert it into paths, and then the machine would move through those paths.
This would work kind of like CNC or laser cutting. The machine would not understand the picture as a picture anymore. It would follow movement commands. The Raspberry Pi 5 would handle the image processing and send movement instructions to the motors.
The automated process would be:
The main function of the machine was to draw a 2D picture automatically. It would take digital artwork and turn it into physical movement. The normal working version would use a marker or pen because that is the safest and easiest way to prove the machine works.
The more advanced idea was a self-tattoo-style machine based on the same motion system, but I did not build or test that. I only used it as a design idea because it helped me think through how the machine would need a tool holder, motion control, and a user interface.
If I continued this project later, I would build and test the pen plotter version first. Once the XY machine worked safely and accurately as a drawing machine, then I could think about different tool heads.
The user interface would run on the Raspberry Pi 5. I wanted it to be simple because I did not want the machine to be hard to use.
The interface would let the user:
For manual operation, I wanted simple jog controls so I could move the carriage by hand through software before running a full automated drawing.
The mechanical parts would come from a mix of reused, laser-cut, and 3D printed parts. The broken Prusa Mini printers would provide the motion hardware. The laser cutter would make the wooden frame. The 3D printers would make the brackets and custom holders.
The assignment also wanted the mechanical parts built and operated manually. My plan was to build the XY frame first and test it by sliding the carriage by hand before powering anything.
I would check that the rails were straight, the belts were tight enough, and the carriage could move smoothly. After that, I would connect the stepper motors and jog the machine slowly from the Raspberry Pi interface.
Since I ran out of time, I did not get to the physical manual testing stage. I am documenting the plan honestly because the machine was not completed.
Since I did not have a full group, my individual contribution was the machine concept and planning. I came up with the idea of using broken Prusa Mini printers, a Raspberry Pi 5, laser-cut wood, and 3D printed mounts to make a drawing machine.
I also planned how the machine would include the required parts of the assignment:
ChatGPT / Astra helped me organize the idea, think through the machine sections, and write the documentation clearly so I could explain what I planned and what actually happened.
If I had more time, I would start by taking apart the broken Prusa Mini printers and saving the motors, belts, rails, and carriage parts. Then I would measure those parts and design a laser-cut wooden frame around them.
After that, I would 3D print the motor mounts, belt holders, and tool holder. Then I would assemble the machine and test the carriage manually before connecting the electronics.
The first working version would be a pen plotter. I would not jump straight into the tattoo-machine idea because the safe way to test the motion system is with a marker first.
I did not complete a physical machine for Week 12. The machine stayed in the concept and planning stage because I was working by myself and ran out of time.
Even though I did not finish the build, this week helped me understand what a machine needs. It needs a real mechanism, a way to actuate it, automation to control it, a useful function, and a user interface so a person can operate it.
My final idea was a drawing machine made from reused Prusa Mini 3D printer parts, controlled by a Raspberry Pi 5, with a laser-cut wooden frame and 3D printed mounts. The more advanced tattoo-machine idea stayed only as a future concept, not a working machine.