Project Overview
This project builds on an existing hybrid solar and hydrogen charging station DAQ system associated with the Department of Mechanical Engineering, College of Engineering — Houston Engineering Center, The University of Texas at Tyler, in collaboration with the Houston Community College Engineering Center of Excellence. The larger station is intended to monitor renewable-energy system behavior across solar, battery, and hydrogen fuel-cell hardware while collecting voltage, current, power, and temperature data for display and cloud-connected telemetry.
My contribution is focused on the DAQ system redesign rather than the original station design. The goal is to make the low-voltage acquisition system easier to understand, easier to reproduce, easier to debug, and more maintainable for future project work.
Existing UT Tyler / HCC Engineering Center System
The redesign work started by reviewing the existing public repository and prior documentation for the hybrid station DAQ system. The previous architecture provided the baseline for the redesign proposal and later ESP32 bench reconfiguration.
Legacy DAQ Context
The existing system documentation describes a local acquisition system using current/voltage sensors, thermocouple sensing, display hardware, I2C device management, and cloud telemetry hardware.
Reason for Redesign
The redesign effort is intended to reduce ambiguity, simplify the low-voltage DAQ path, improve repeatability, and create a more maintainable path for sensor bring-up, display output, and cloud upload.
My Role
My role has focused on reviewing prior project documentation, identifying architecture and wiring ambiguity, proposing a simplified ESP32-based DAQ direction, creating submitted redesign documentation, and performing an initial bench reconfiguration of the low-voltage sensor system.
My work includes ESP32 firmware development, I2C sensor scanning, OLED display integration, INA228 current/voltage sensor bring-up, MCP9601 thermocouple troubleshooting, 2N7000 MOSFET level-shifter wiring, power-rail planning, ThingSpeak telemetry preparation, and documenting the system state for the project stakeholders.
Technical Summary
The redesign is being treated as a staged engineering recovery effort: first understand the old system, then propose a cleaner architecture, then validate hardware one layer at a time before publishing final manual updates.
Electrical Channels
The DAQ design targets three electrical monitoring channels corresponding to fuel-cell, battery, and solar-panel measurements. These channels are measured with current/voltage sensor modules.
Thermocouple Channels
Two Type-K thermocouple channels are part of the sensor stack. These are currently the main unresolved sensor reliability issue in the ESP32 bench configuration.
Display and Telemetry
The redesign includes local OLED display output and planned ThingSpeak cloud telemetry. The bench code skips cloud posting until Wi-Fi credentials and write keys are inserted.
I2C Bus Work
Current work has focused heavily on I2C bus validation, address discovery, level shifting, and separating proposal architecture from the actual bench configuration used for early testing.
Redesign Documentation Milestones
Documentation Review
I reviewed previous project files and materials to understand the existing station DAQ architecture, sensor stack, display path, and cloud-telemetry direction before modifying hardware.
Proposed Revised Connection Scheme 1.2
I submitted a proposed ESP32-only DAQ architecture using a regulated 5 V supply, ESP32 GPIO21/GPIO22 for the main I2C bus, a TCA9548A I2C multiplexer, three electrical sensor branches, two MCP9601 thermocouple branches, an OLED branch, and ThingSpeak upload support.
ESP32 All-in-One Firmware Concept
I developed a proposed ESP32 all-in-one DAQ/OLED/ThingSpeak firmware concept with non-fatal OLED initialization, current-sensor model selection, sensor polling, and staged bring-up logic.
Hybrid Station EOD Update — 04/01/2026
After initial reconfiguration, I submitted an end-of-day update documenting the actual bench wiring, detected I2C addresses, working OLED/serial behavior, unresolved thermocouple behavior, and planned rewiring/debug steps.
Initial ESP32 Bench Reconfiguration
The first bench reconfiguration temporarily removed the TCA9548A multiplexer from the test setup and used a direct I2C bus for faster bring-up and address validation. This was not the final proposed architecture; it was a practical debugging step to determine which devices could be detected and initialized.
Bench Wiring Summary
- ESP32-S3 Super Mini used for bench testing
- USB-C power during the bench configuration
- GPIO8 used as low-side SDA
- GPIO9 used as low-side SCL
- OLED connected on the 3.3 V low-side I2C bus
- Two 2N7000 MOSFETs used for bidirectional I2C level shifting
- INA228 sensor chain connected on the shifted 5 V bus
- MCP9601 thermocouple chain connected on the shifted 5 V bus
Detected I2C Addresses
0x3C— OLED display0x41— current/voltage sensor0x44— current/voltage sensor0x45— current/voltage sensor0x65— Type-K thermocouple board0x67— Type-K thermocouple board
Bench Validation State
| Subsystem | Observed State | Portfolio Interpretation |
|---|---|---|
| OLED Display | Initialized and rotated structured data screens | Partially validated display path |
| Serial Debug | Serial connection from ESP32 to Arduino IDE worked | Validated bench debug path |
| Electrical Sensors | Three current/voltage sensor addresses detected | I2C detection validated; measurement calibration still requires final verification |
| Thermocouples | Addresses detected, but thermocouples were not working properly | Known unresolved debugging item |
| Wi-Fi / ThingSpeak | Credentials and API keys still needed to be inserted | Telemetry path prepared but not fully validated |
Current Technical Challenges
Power-Rail Reliability
A likely instability source is attempting to power the full 3.3 V and 5 V sensor rails from the microcontroller board pins. The next revision should use external regulated sensor rails while keeping grounds common.
Thermocouple Reliability
The MCP9601 boards were detected on the I2C bus, but readings were not yet reliable. This needs focused testing of power, pull-ups, addressing, library behavior, and thermocouple wiring.
ESP32-S3 Mini Repeatability
Early testing showed poor repeatability with the ESP32-S3 Mini boards used during experimentation. Thirteen out of fifteen tested boards failed to operate reliably, producing an observed failure rate of approximately 87% for that tested batch.
Architecture Finalization
The final architecture still needs to be selected after power and sensor reliability issues are resolved: direct ESP32 bus, ESP32 with TCA9548A channel isolation, or a split controller/gateway approach.
Next Steps
The next hardware revision should avoid using a voltage divider as a power source. Voltage dividers are useful for signals and measurements, not for powering sensor rails. The 3.3 V rail should be produced with a real regulator.
Recommended Power Architecture
- External LiPo or bench supply feeds a regulated 5 V boost converter
- Regulated 5 V output powers the 5 V sensor rail
- 5 V rail feeds a dedicated 3.3 V regulator for the 3.3 V sensor rail
- ESP32 ground, sensor ground, and external supply ground remain common
- Sensor bus is brought up one branch at a time
Planned Bring-Up Order
- Verify stable 5 V and 3.3 V rails under load
- Verify OLED alone
- Verify I2C level shifter behavior
- Verify one INA228 channel
- Verify all three INA228 channels
- Debug MCP9601 thermocouple channels individually
- Restore Wi-Fi and ThingSpeak upload after sensor readings are stable
- Update the project manual after the final solution is validated
Public Documentation Boundary
This portfolio page summarizes my contribution without posting internal project documents, unpublished manuals, lab-only file links, full submitted code, or sensitive project materials. More detailed schematics, manual excerpts, photos, and code can be added later if approved by the appropriate UT Tyler / HCC Engineering Center project stakeholders.
This page is intentionally written as a contribution summary, not as a claim of ownership over the original UT Tyler / HCC Engineering Center hybrid station research system.
Public Reference
The redesign builds from the existing public project repository and related documentation. The full final redesign documents and internal manual updates will be handled separately after the system is stable and posting permissions are clarified.
Related Work / Contact
This project connects to my broader work in embedded systems, robotics, instrumentation, sensor integration, DAQ, power systems, and electromechanical prototyping.