My final project is a smart battery checker and charger system. The purpose of this project is to safely check battery voltage, display information on an ESP32 touch screen, and charge lithium batteries using separate charger modules. The project combines electronics, PCB design, embedded programming, fabrication, packaging, and system integration into one complete device.

What Does It Do?

The smart battery checker and charger measures battery voltage and displays the information on an ESP32 touch screen. The system also supports charging batteries using USB Type-C charger modules. A button allows the user to switch between different display modes and functions on the screen.

The project was designed to support both single-cell 3.7V lithium batteries and larger battery packs using separate charging systems.

Project Overview Video

This video shows the completed project assembled together and switching between different modes on the ESP32 screen.

PCB Milling Video

This video shows the CNC milling process used to make the custom PCB for the project.

Who Has Done What Beforehand?

Many people have created battery chargers and voltage readers before, but I designed my own version that combines a custom PCB, ESP32 touch screen, charger modules, boost converters, and a custom enclosure into one system.

I researched lithium battery charging systems, ESP32 displays, voltage dividers, boost converters, and PCB design before creating my own project.

What Sources Did I Use?

I used online tutorials, component datasheets, YouTube videos, Arduino libraries, Fab Academy documentation, and help from Sir Sparks, my ChatGPT companion. Sir Sparks helped explain wiring, troubleshoot problems, help with coding, system integration, and documentation throughout the project.

What Did I Design?

• A custom PCB
• A battery voltage divider circuit
• A custom enclosure and lid
• An ESP32 touchscreen interface
• The wiring layout and system integration
• The battery charging and checking setup

Materials and Components Used

• ESP32 touch screen
• Custom milled PCB
• Voltage divider resistors
• Single-cell lithium battery charger module
• 2S lithium battery charger module
• Boost converter
• Push button
• Battery connectors
• Wiring and solder
• 3D printed enclosure
• USB Type-C charging modules

Where Did the Parts Come From?

Most components were purchased online through Amazon and electronics suppliers. The PCB was designed and milled by me using the Makera Carvera CNC machine. The enclosure parts were designed using CAD software and fabricated using 3D printing and laser cutting processes.

Estimated Cost

• ESP32 screen - approximately $15
• Boost converter - approximately $5
• Battery charger modules - approximately $10
• PCB materials - approximately $5
• Wires, resistors, and connectors - approximately $10
• 3D printing materials - approximately $10

Estimated total cost: around $50-$60.

PCB Milling and Electronics Production

The PCB was designed and milled using the Makera Carvera CNC machine. The PCB includes the voltage divider and wiring connections used to connect the ESP32 screen and battery system.

The PCB milling process required generating toolpaths, soldering components, and testing the board using a multimeter. During development, I had to redesign parts of the PCB to improve spacing between traces and pads.

System Integration and Internal Components

The project combines multiple electronic systems together into one working device.

The ESP32 screen works as the user interface. The custom PCB connects the voltage divider and battery reading system. The boost converter helps provide stable voltage to the electronics. The charger modules allow lithium batteries to be charged safely using USB Type-C connections.

A push button was added to allow switching between different modes and displays on the screen.

Programming and Assembly

The ESP32 was programmed using the Arduino IDE and TFT_eSPI libraries. The code reads the battery voltage through the voltage divider and displays information on the touch screen.

The assembly process included soldering electronics, wiring modules together, fitting the components inside the enclosure, and testing the system step by step.

Tools and Processes Used

• Makera Carvera CNC machine
• Arduino IDE
• ESP32 programming
• PCB milling
• Soldering
• 3D printing
• CAD design
• Laser cutting
• Voltage testing with multimeter

Questions Answered During Development

• How can the ESP32 safely read battery voltage?
• How can charging and voltage reading work together?
• How can multiple modules fit into one enclosure?
• How can the system switch between display modes?
• How can power be safely managed using boost converters and charger boards?

What Worked?

The ESP32 screen powered on successfully and displayed information. The PCB was successfully milled and soldered. The charger modules worked correctly, and the system was able to read battery voltage and switch between different display modes.

The enclosure successfully held the electronics together and allowed access to the charging ports and screen.

What Did Not Work?

Some PCB trace spacing issues caused problems during milling and required redesigns. Some enclosure holes needed resizing so components could fit properly. There were also coding and wiring troubleshooting issues during development.

Some early tests caused flickering or unstable readings that had to be fixed through code changes and wiring improvements.

How Was It Evaluated?

The project was tested by connecting batteries, measuring voltage, displaying information on the screen, testing charger modules, and switching between display modes. The system was evaluated by checking if the electronics powered correctly and if the user interface displayed the expected information.

Implications of the Project

This project shows how electronics, fabrication, programming, and system integration can be combined into a useful tool. The project could be expanded in the future with more charging modes, improved battery monitoring, additional safety systems, and a more advanced interface.

Processes Included in This Project

• 2D design
• 3D design
• Additive fabrication - 3D printing
• Subtractive fabrication - CNC milling and laser cutting
• Electronics design and production
• Embedded programming
• System integration
• Packaging and enclosure design

Final Thoughts

This project brought together many of the skills learned throughout Fab Academy. It required problem solving, electronics work, programming, fabrication, testing, redesigning, and system integration.

One of the biggest accomplishments was combining all of the separate systems into one working device that can check battery voltage and charge batteries while displaying information on an ESP32 touch screen.

I also used Sir Sparks, my ChatGPT companion, throughout the project to help explain concepts, troubleshoot problems, help with coding, wiring, planning, and documentation.