SOLAR COLLECTOR
A project from the Red Cross to develop a solar heated waste processing system for a biodigester, a device used to treat waste in refugee camps.
AUTOMATED TEMPERATURE LOGGER
An Arduino temperature logging system that automatically records and logs temperature data to a text file, useful for remote experiments.
FOOD 3D PRINTER
A food 3D printer capable of creating customizable shapes from food paste. Reflects application of full design methodology to fabricate a functional device.
PEN PLOTTER
A CNC-style pen plotter that uses g-code commands to draw images automatically. Reconfigured design of Food 3D Printer project.
REVERSE ENGINEERED PEPPER GRINDER
A reverse engineered design of a pepper grinder, including CAD assembly and 3D prototyping.
automated temperature logger
humanitarian product development
This Arduino project was developed along with the Biodigester Thermal System to remotely conduct experiments on the solar collector. The circuit automatically takes temperature readings of the ambient, inlet, and outlet temperatures in the solar collector and saves this data to a text file stored on an SD card. The data can then be analyzed using the Solar Analysis GUI program, which exports the results of the analysis to an Excel file.
Software
The circuit was programmed in Arduino. There are two main parts of the code: 1) modifying open source code to read data from multiple temperature sensors, and 2) displaying the temperatures, time, and date on an LCD screen and saving that data to an SD card. The circuit includes:
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Potentiometer to adjust LCD screen contrast
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Two buttons to adjust time and date
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Four DS18B20 temperature sensors
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RTC (real time clock) module
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MicroSD card module
Reference on my GitHub: https://github.com/johnathantran/autotemplogger
Hardware
The circuit box is laser cut acrylic designed in SolidWorks. The LCD screen and temperature sensors were soldered to jumper wires for better connection.
biodigester thermal system
humanitarian product development
Testing solar collector prototype
This exciting project is part of a new program at The University of Texas at Austin called Humanitarian Product Development. Our team, Team Biodigester, is working with the International Federation of the Red Cross to further develop a solar heated waste processing system for use in refugee camps.
Specifically, we are creating a thermal control system for a "biodigester", a large rubber bag that facilitates the environment for bacteria to naturally break down latrine waste. The bacteria digest waste best in an optimal temperature range of 30-40 degrees Celsius. We will determine the best solar collector design possible to maximize efficiency in reaching this temperature range.
As the Logistics & Procurement Coordinator for this project, I am managing our $5000 budget, assembling our bill of materials, and designing the optimal solar collector through experimentation and analytical models.
The Automated Temperature Logger and Solar Analysis GUI are both projects associated with the Biodigester Thermal System.
More project info can be found on the official project site: sites.utexas.edu/biodigester
Schematics of the biodigester system and our prototype (using a trash can full of water as a substitute for the biodigester) are shown below.
Project Schematic
Prototype Schematic
food 3d printer
design and fabrication
phase I. planning
Before my team and I started designing the printer, we created a subsystem function tree to visualize how energy and information would flow throughout our food printer system. This would enable us to determine the best way to integrate those flows into our physical design.
phase II. design
CAD Design
Our team used SolidWorks to build a complete CAD assembly of the food 3D printer to visualize the integration of all aspects of our leading design into the final product. We chose to move the extruder and print bed using belts and pulleys, and extrude the food through a syringe with a lead screw mechanism.
Electronics
As the mechatronics lead, I integrated the electronics control system into our food 3D printer to supply power, program and calibrate motor movement, and ensure that our system could accurately read g-code files.
Below is a wiring schematic I developed of our microcontroller, an Arduino Mega, and electronics hardware.
phase III. fabrication
Our food 3D printer is meant to be easily fabricated by the average DIY enthusiast. Based on this customer requirement, we focused on keeping the engineering of the printer as minimalist as possible. Our final design consists of:
Frame
Base fabricated from laser cut wood, supports from aluminum T-slots. The print bed is also laser cut acrylic.
Belt and Pulley System
A belt and pulley system drives both the extruder head and print bed movement. The belt is secured by zip ties for easy installation and re-tensioning.
Extruder
A large syringe attached to a threaded rod and two guide rails. A stepper motor above the extruder box is attached to a lead screw that drives the syringe down.
Software
See my GitHub repo for this project for a full guide on how this project was fabricated and programmed:
https://github.com/johnathantran/Marlin-Food-3D-Printer
The following software was used for this project:
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Arduino
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Marlin firmware (commonly used tp drive custom 3D printers)
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Slic3r (to convert SolidWORKS drawing files to g-code)
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Pronterface (to run g-code)
pen plotter
design and fabrication
the redesign process
The food 3D printer project can easily be repurposed as a pen plotter with a few hardware and software adjustments. The pen plotter takes a g-code file as input and draws the design accordingly on the print bed. The g-code is generated using Inkscape, a graphics editor program that can convert SVG image files to g-code.
Just like the food printer, the pen plotter uses the Arduino Mega, a RAMPS 1.4 CNC shield, and 3 stepper motors to drive its movement. I only had to rewire the 3rd stepper motor from the Extrusion pinouts to the Z-axis pinouts to lift the pen up and down. Of course, I also had to replace the syringe with a pen carriage. I tackled this project during the midst of COVID-19 and therefore lacked access to a 3D printer to custom design a proper carriage, so I had to make do with some makeshift materials lying around (as you can probably tell...)
Software documentation on my GitHub: https://github.com/johnathantran/Pen-Plotter
drawing samples
reverse engineered pepper grinder
rapid prototype
phase I. planning
I worked on this project with three other mechanical engineering students to develop a prototype of a reverse engineered pepper grinder. I developed the housing and core components of the grinding mechanism, shown left as orthographic drawings.
phase II. assembly
In the initial planning stage, my group had to consistently work with one another to make sure that our dimensions matched. Once we had developed each of our individual parts in Solidworks, we assembled the final product, shown left as a complete assembly.
phase III. prototyping
After assembly, we 3D printed each of our parts to provide a physical, true to size model of the pepper grinder. Shown right are each of the separate components of the final rapid prototype.