AD Wandler Validation Board

ADC Validation Platform

A modular testbed for evaluating analog signal chains in motor control applications

⚠️ Development Status

Work in Progress: This repository is actively developed as part of my Master’s project at HTWG Konstanz. The current README is a draft and will be expanded with hardware designs, firmware, and validation results.

📌 Overview

This repository provides design files, firmware, and validation tools for a custom ADC validation board, developed as an extension to my Bachelor’s thesis the "DIY Power PCB" (HTWG Konstanz, 2025). While the original thesis used the ESP32’s internal ADC (limited by nonlinearity and noise), this platform focuses on:

Core Objectives

1. External ADC Validation:

   • Replace the ESP32’s internal ADC with a MCP3208/MCP3008 (12/10-bit, 8-channel) or an AD7265 (12bit, dual 3-channel SAR) to quantify improvements in noise floor and linearity for current measurements.
   • Key question: Does an external ADC justify the added complexity/cost in motor control applications?

2. Full Analog Chain Analysis:

   • Evaluate the entire signal path:
     • Shunt-based current sensing + Operational amplifier (e.g. [MCP6002], [TLV906],...) for low-side measurement
     • Shunt-based current sensing + Currentmeasure amplifier (INA240) for inline measurement
     • Phase current sensors (e.g., [ACS712], [ACS723]...)
   • Goal: Identify the weakest link in the chain (ADC vs. sensors vs. OPVs) and optimize cost/performance trade-offs.

3. BLDC Motor Control Context:

   • Target application: Precise phase current measurement for FOC (Field-Oriented Control) of BLDC motors.
   • Compare budget vs. high-end components to determine where to invest for maximum accuracy.

🔗 Related Work

• Bachelor’s Thesis: "DIY Power PCB" (PDF, German) – Foundation for this project, focusing on the ESP32-based power distribution board.
• Master’s Project: Extends the thesis by adding modular ADC validation and analog chain analysis.

🛠️ Features

• Hardware: -Analog to Digital Converter(ADC):
  • [MCP3208] with [12]-bit resolution, 100ksps, 8-channel
  • [AD7265] with [12]-bit resolution, 1MSPS, dual 3-channel differntial(=2 seperate 6-channle single-ended)
  • [ESP-32] with [12]-bit resolution, 25ksps, 18-channel
  • optional [MCP3008] with [10]-bit resolution, 200ksps, 8-channel (shares Footprint with MCP3208) -Current measurement
  • [Shunt]
    • [INA240]
    • [MCP6002]
    • [TLE]
• Firmware:
  • Written in C/C++ using [ESP-IDF]
  • Supports SPI communication and PWM calibration
• Validation:
  • Automated test scripts (Python)
  • Noise floor analysis and linearity plots

📂 Repository Structure

adc-validation-board/
├── hardware/          # KiCad schematics, PCB layouts, BOM
├── firmware/          # Source code for MCU
├── software/          # Test scripts (Python/MATLAB)
├── docs/              # Datasheets, thesis excerpts, results
└── images/            # Photos, plots, diagrams

🚀 Getting Started

Prerequisites

• Hardware: [List components, e.g., ADC chip, MCU, power supply]
• Software:
  • KiCad for PCB design
  • Python 3.8+ for test scripts

Installation

1. Clone the repository:

 git clone https://github.com/your-username/adc-validation-board.git

2. Open the firmware in [your IDE] and flash it to the MCU.
3. Run validation tests:

 cd software/tests
 python3 noise_analysis.py

📊 Validation Results

Key findings from the thesis:

• Noise floor: [X] µV RMS @ [sampling rate]
• INL/DNL: [Y] LSB (see plot [blocked])
• Temperature drift: [Z] ppm/°C

Example: Noise spectrum of the ADC at 1 kSPS

🔗 Full results in the thesis [blocked]

🎓 Thesis Summary

Abstract

[2–3 sentences summarizing your thesis goals, e.g.:
"This work evaluates the suitability of the [ADC Model] for precision applications in embedded systems. A custom validation board was designed to measure noise, linearity, and temperature effects, achieving [key result] under [conditions].")

Key Contributions

• Designed and assembled a low-noise ADC validation platform.
• Developed firmware for automated calibration and data logging.
• Validated performance against industry standards (e.g., [reference]).

📄 Download the full thesis (PDF)

🔧 Built With

• Hardware: KiCad, [ADC Model], [MCU Model]
• Firmware: C/C++, [ESP-IDF/PlatformIO]
• Analysis: Python (NumPy, Matplotlib), [MATLAB/Octave]

🤝 Contributing

Contributions are welcome! Open an issue or submit a pull request for:

• Bug fixes
• Additional test cases
• Documentation improvements

📜 License

This project is licensed under the MIT License – see LICENSE for details.

📬 Contact

Fabian Zaske – your.email@example.com
🔗 Portfolio/Website | LinkedIn

"Precision matters – in bits and in life."