---
title: "esp-now-differential-probe"
url: "https://maker.wiznet.io/TheoIm/projects/esp-now-differential-probe/"
markdown_url: "https://maker.wiznet.io/TheoIm/projects/esp-now-differential-probe/md"
type: "UCC: User Created Content"
author: "dudeku"
author_url: "https://github.com/dudeku/esp-now-differential-probe"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "dudeku"
original_url: "https://github.com/dudeku/esp-now-differential-probe"
published: "2026-06-05"
language: "en"
hardware: ["WIZnet W5500"]
likes: 0
views: 265
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# esp-now-differential-probe

> Industrial measurement platform combining ESP-NOW sensor nodes and a W5500 Ethernet gateway with 16-channel ADC, FreeRTOS, and custom PCB.

Original author: dudeku (source: https://github.com/dudeku/esp-now-differential-probe)

## Components

- **WIZnet W5500** x 1 ([docs](https://docs.wiznet.io/Product/Chip/Ethernet/W5500))

WIZnet parts: W5500 ([Datasheet](https://docs.wiznet.io/Product/Chip/Ethernet/W5500/datasheet?utm_source=maker&utm_medium=project&utm_campaign=w5500), [product hub](https://maker.wiznet.io/products/w5500/))

## Article

## Why This Project Stands Out

Many embedded measurement systems stop at data acquisition. This project goes significantly further.

It combines:

- Distributed wireless measurement nodes using ESP-NOW

- Local high-resolution 16-channel ADC acquisition

- FreeRTOS-based concurrent task execution

- Ethernet-based industrial data delivery

- Custom-designed hardware including PCB, Ethernet interface, and analog front-end

- Python-based capture and visualization tools

The result is not simply a sensor node connected to a network.

It is a complete measurement infrastructure designed from the PCB level through to data analysis software.

---

## System Architecture

![](https://maker.wiznet.io/upload/ckeditor5/199709372%5F1780654699%2Epng)

**Generated By GPT**

### Hybrid Network Concept

The project deliberately separates networking responsibilities.

**Wireless Edge Layer**

- Distributed measurement probes

- Reduced field wiring

- Easier installation across large physical areas

- Low-latency ESP-NOW communication

**Wired Backhaul Layer**

- Reliable Ethernet transport

- Deterministic communication path

- Stable long-duration acquisition

- Simplified integration with servers and SCADA systems

This hybrid architecture directly addresses one of the most common industrial deployment problems: balancing installation flexibility with network reliability.

---

## Where WIZnet Fits

The W5500 is not used as an external shield or evaluation module.

Instead, it is integrated directly into the custom hardware design as a native system component.

### Hardware-Level Integration

The gateway board incorporates:

- W5500 Ethernet controller

- RJ45 interface

- Dedicated SPI bus

- Ethernet link monitoring

- Hardware reset circuitry

The design uses the W5500 LQFP-48 device directly on the PCB, making this a true product-level implementation rather than a development-board demonstration.

---

## Hardwired TCP/IP as an Embedded TOE Example

One of the most technically interesting aspects of this project is its use of the W5500 as a practical TCP Offload Engine (TOE).

In conventional embedded Ethernet systems:

```plaintext
MCU
 ├─ ADC Processing
 ├─ Wireless Handling
 ├─ RTOS Tasks
 └─ TCP/IP Stack
```

The processor must manage networking alongside all application workloads.

In this design:

```plaintext
ESP32-S3
 ├─ ADC Acquisition
 ├─ Calibration
 ├─ ESP-NOW Communication
 ├─ JSON Serialization
 └─ RTOS Scheduling

W5500
 ├─ TCP
 ├─ IP
 ├─ Socket Management
 └─ Ethernet Protocol Handling
```

The networking workload is offloaded to dedicated silicon.

This allows the ESP32-S3 to focus on measurement and data-processing tasks while the W5500 independently handles Ethernet communication.

For embedded engineers, this represents a real-world example of TOE deployment in a resource-constrained measurement system.

---

## Engineering Complexity

The value of this project is not a single feature but the interaction of multiple subsystems operating simultaneously.

### High-Resolution Measurement

- LTC2449

- 16 channels

- 24-bit delta-sigma conversion

- Differential signal acquisition

### Real-Time Software Architecture

- FreeRTOS multitasking

- Independent ADC acquisition tasks

- Ethernet server task

- Watchdog supervision

- Core affinity assignment

### Network Aggregation

- Local ADC measurements

- Remote ESP-NOW measurements

- JSON serialization

- TCP-based Ethernet serving

All of these functions execute concurrently on the gateway.

This makes the project significantly more sophisticated than typical Arduino Ethernet examples.

---

## Why It Is More Than "Raspberry Pi + USB Dongle"

A common approach to measurement systems is:

```plaintext
ADC → USB → Raspberry Pi
```

Networking is often added afterward through external adapters.

This project takes a fundamentally different engineering approach.

The Ethernet subsystem is designed into the hardware architecture from the beginning.

The W5500 is:

- Included in the schematic

- Included in the PCB layout

- Assigned a dedicated SPI bus

- Integrated with RTOS services

- Used as part of the acquisition pipeline

Networking is therefore a first-class system function rather than an afterthought.

That distinction makes this project a valuable engineering reference for developers building industrial gateways, DAQ systems, and edge measurement platforms.

---

## Key Takeaways

- Hybrid architecture combining ESP-NOW wireless sensing and Ethernet backhaul

- W5500 directly integrated into a custom KiCad PCB

- Practical Hardwired TCP/IP and TOE deployment example

- 16-channel 24-bit measurement subsystem

- FreeRTOS multitasking with concurrent acquisition and networking

- End-to-end open-source stack from hardware design to analysis software

- Strong reference design for industrial measurement gateways and distributed DAQ systems

---

## Recommended Tags

#W5500
#HardwiredTCPIP
#TOE
#ESP32S3
#ESPNow
#HybridNetwork
#IndustrialIoT
#MeasurementSystem
#DAQ
#FreeRTOS
#CustomPCB
#KiCad
#EthernetGateway
#24bitADC
#DistributedSensing

---

Source: https://maker.wiznet.io/TheoIm/projects/esp-now-differential-probe/