Juan Aguarón

Thank

As part of a spherical robot prototype I designed a 1:10 gearbox for NEMA17 stepper motors. Since both the worm and the pinion were of low quality, the 3D printed parts were conceived in a way that made the whole process of tuning easy.

At Universidad Politécnica de Madrid I took care of the overall design (mechanics and electronics) of a farming robot prototype. Nicknamed “Lulubelle”, it was a 3DOF (rotational-prismatic-prismatic) crane-like robot with a set of tools for carrying out several tasks in a controlled environment. 

It is worth mentioning its mechanical counterweight system, which using simple physics kept its center of gravity inside its area of support. It was built using standard, off-the-shelf parts as well as 3D printed parts. 

I designed a switch for high currents for my Bachelor’s thesis at TU Graz, Austria. In essence, it was an H-Bridge that could switch currents up to 30A, and it was later used in a materials science experiment.

As an assignment at TU Graz I wrote a piece of code that implemented a kind of filtering known as coherence-enhancing diffusion. Its results were very appealing, for they remind of a painting:

After having helped build and modify a Prusa i2 3D printer, I felt it was time to get my own printer. In early 2014 I started gathering the parts, and by mid 2015 I finished building it. 

Its key specs are the following:

Stainless steel frame (P3Steel)

Aluminium heatbed (MK3 ALU)

SAV MKI dedicated electronics

All-metal nozzle (Leonozzle V1.0)

I was comissioned a pair of 3D printed shoe soles that were to be used in a biomedical application. Due to its large size and to the high accuracy that was needed I also took part in the final stages of the project.

The emergency light switch of an early 90s Fiat 500 had stopped working. Since this part was no longer manufactured, I was asked to build a replacement for it.

It was trickier than expected because this switch controlled at the same time several circuits of the car, enabling or disabling the emergency lights, the turn signals and other displays. The pinout of the connector was reverse-engineered with great care. A small board with a few parts was developed, and it was integrated into the car with success.

The paint shaker machine above was being used in a laboratory as an industrial mixer, but it could only work for a certain number of minutes (1, 3 or 5) which were not adjustable. I was asked to change that, since the lab staff needed to shake a specific mixture for 15 seconds.

Some reverse engineering was needed in order to understand how the machine had been built. Due to the operation intervals being hardcoded in the internal logic, there was no way to change their duration without modifying the code.

The problem was solved using in an unconventional way the emergency stop switch of the machine. I designed a small circuit that could read the state of the machine switches, as well as activate or deactivate the emergency switch. Whenever the 1-minute button was pressed, a microcontroller located on the board I designed started a countdown. When it reached zero a relay ‘simulated’ an emergency switch press, thus stopping the machine.

Still a work in progress, I designed and built five units of a custom T-shirt with embedded LED lights which responded to light and sound. 

The setup consisted of both the T-shirt and a small pouch or belly band in which the USB batteries and electronics were carried. It proved to be a mistake to use 12-Volt LED stripes, since the required boost converter was excessive. A much better option would have been to choose LiPo batteries. Still, a good enough boost circuit was built.

The design also included a 16-channel LED driver (TLC5940), which was commanded by an Arduino Nano.

This seemingly simple lamp took several months to be built: developing the internal electronics was a much harder task than I expected.

It features a unique custom-made capacitive sensor running all under the wooden top of the lamp. This effectively transforms the whole surface into a switch with no movable nor metallic parts, a technical feat of which I am particularly proud.

Due to the growing amount of lab equipment I was facing, I designed and built a custom piece of furniture where I could work comfortably.

Having a natural tendency towards clutter, I wanted this setup to be as tidy as possible. That is why I ran all the wiring through a small box located at the bottom shelf.

This way I could easily connect probes to both oscilloscope channels, or standard jacks to the power supply or wave generators.