s0tool

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📖 Table of Contents

• Overview
• Features
• Quick Start
• Hardware Requirements
• DIY Build
• Installation
• Configuration
• Compatible Devices
• Troubleshooting
• Contributing
• Support
• License

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🌟 Overview

The S0tool is an ESPHome-based device that transforms regular water and energy meters into smart meters. Seamlessly integrate with Home Assistant to monitor real-time consumption and optimize your usage.

S0tool Device	Home Assistant Dashboard

📰 Latest Updates

🎉 Latest Firmware Updated! (07/11/2026) Visit https://s0tool.nl for complete documentation and guides.

🇳🇱 Dutch Version Voor de Nederlandse versie, bezoek Huizebruin.nl

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✨ Features

• 💧 Water Meter Monitoring - Track water consumption in real-time
• ⚡ Energy Meter Support - Monitor kWh usage from S0 pulse outputs
• 🏠 Home Assistant Integration - Native ESPHome integration with auto-discovery
• 📊 Energy Dashboard Compatible - Display data in HA Energy Dashboard (v2022.11+)
• 🔄 OTA Updates - Update firmware wirelessly through ESPHome
• 🌐 Easy Web Installation - Flash firmware directly from your browser
• 📱 Real-time Monitoring - Instant updates on consumption
• 🎯 Multiple Meter Support - Connect both water and energy meters simultaneously

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🚀 Quick Start

Requirements

Software	Minimum Version
Home Assistant	v2026.10.0+
ESPHome	v2026.10.0+

Specifications:

• Wi-Fi: IEEE 802.11 b/g/n 2.4GHz
• Compatible with: Wemos D1 Mini V1 or V3.0 ESP8266
• Power: USB 5V, 1A minimum

Installation Methods

🌐 Browser Installation (Recommended)

1. Visit https://s0tool.nl/installation.html
2. Connect your S0tool via USB
3. Click “Install” and follow the wizard
4. Compatible with Chrome, Edge, and Opera browsers

🏠 Home Assistant Auto-Discovery

After connecting to Wi-Fi, the S0tool will automatically appear in Home Assistant under Settings → Devices & Services.

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🛠 Hardware Requirements

Option 1: Purchase Pre-Built

Order from Huizebruin Shop 🚚 Currently shipping to: multiple countries so check it out on our shop

Option 2: DIY Build

Components Needed:

Component	Where to Buy
Wemos D1 Mini ESP8266	AliExpress • Amazon • Opencircuit
NPN Sensor (5V)	AliExpress • Amazon • Opencircuit
10K Resistor	AliExpress • Amazon • Opencircuit
USB Cable & 5V Power Adapter	Bol.com • Opencircuit

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🔧 DIY Build

Wiring Diagram

Connection Steps

1. Connect 10K resistor between 5V and D2 pins
2. Connect D2 to NPN sensor signal wire
3. Connect NPN sensor GND to Wemos GND
4. Connect NPN sensor 5V to Wemos 5V

⚠️ Important: Use NPN sensors rated for 5V only (not higher than 6V) Recommended Sensor: LJ18A3-8-Z/BX-5V

Sensor Connection Examples

Standard NPN Sensor Connection:

Cyble Sensor V2 Connection:

Note: Requires 10K resistor between GND and D2

Meter Compatibility

💧 Check if your water meter is compatible: View Compatibility List

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📥 Installation

Step 1: Install USB Drivers

First, install the CH340 drivers for communication: Download CH340 Drivers

Step 2: Flash Firmware

Browser Method (Easiest):

1. Visit https://s0tool.nl/installation.html
2. Connect S0tool to your PC via USB
3. Select configuration type
4. Click “Install” and follow prompts

Manual Method:

1. Install Home Assistant & ESPHome
2. Connect Wemos D1 Mini via USB
3. Access Wi-Fi: S0tool
4. Navigate to: 192.168.4.1
5. Enter your Wi-Fi credentials
6. Wait for device to connect
7. Add device in Home Assistant

Step 3: Add to Home Assistant

The S0tool will automatically appear in: Settings → Devices & Services → ESPHome

Click “Configure” to complete setup.

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⚙️ Configuration

Translations (entity names)

The entities are named in Dutch by default (Actuele energie, Totaal opgebracht, …). Use the files in s0tool_translations/ to show them in your own language in Home Assistant: Nederlands, English, Deutsch, Français. Only the displayed name changes; the entity IDs stay the same, so dashboards, utility meters and the Energy dashboard keep working.

1. Copy the s0tool_translations folder to your Home Assistant config/ folder.
2. Add one language to configuration.yaml:

homeassistant:
  customize: !include s0tool_translations/s0tool_eng.yaml

3. Restart Home Assistant, or run Developer tools → YAML → Reload customizations.

Dutch (default)	English	Deutsch	Français
Actuele energie	Current power	Aktuelle Leistung	Puissance actuelle
Totaal opgebracht	Total energy	Gesamtenergie	Énergie totale
watermeter Totaal	Water meter total	Wasserzähler gesamt	Compteur d’eau total

See s0tool_translations/README.md for details and how to add another language.

Home Assistant Utility Meters

1. Create utility meter configuration:

Create folder: config/utility_meter/

Create file: utility.yaml

utility_meter:
  # Water meter tracking
  waterverbruik_kwartier:
    source: sensor.watermeter_totaal
    cycle: quarter-hourly
  waterverbruik_per_uur:
    source: sensor.watermeter_totaal
    cycle: hourly
  waterverbruik_dag:
    source: sensor.watermeter_totaal
    cycle: daily
  waterverbruik_week:
    source: sensor.watermeter_totaal
    cycle: weekly
  waterverbruik_maand:
    source: sensor.watermeter_totaal
    cycle: monthly

2. Include in configuration.yaml:

utility_meter: !include utility_meter/utility.yaml

📁 View Complete Utility Meter Config

Update Notifications

Enable automatic update checks:

homeassistant:
  packages: !include_dir_merge_named packages/

Create packages/s0tool.yaml:

sensor:
  - platform: rest
    resource: https://api.github.com/repos/huizebruin/s0tool/releases/latest
    name: s0tool_version_github
    unique_id: s0tool_github_version
    value_template: '{{ value_json.tag_name }}'
    scan_interval: 3600

template:
  - binary_sensor:
      - name: "S0Tool update online"
        unique_id: s0tool_up_to_date
        state: >
          {% set a = states('sensor.s0tool_versie_github') %}
          {% set b = states('sensor.s0tool_versie') %}
          {{ version(a) > version(b) }}
        device_class: update

Dashboard Update Card:

type: conditional
conditions:
  - entity: sensor.s0tool_up_to_date
    state_not: 'True'
card:
  type: markdown
  content: The S0tool is not up to date with the GitHub version.

Automation Blueprint

Get notified when new versions are available!

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💧 Energy Dashboard Integration

From Home Assistant v2022.11.X, water meters can be added to the Energy Dashboard!

Energy Dashboard	S0tool Dashboard

Adding to Energy Dashboard

1. Go to Settings → Dashboards → Energy
2. Add water meter: Look for watermeter stand
3. Add S0 port: Look for Totaal opgebracht

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⚡ Energy Meter Support

Compatible kWh Meters

Perfect for monitoring:

• 🌞 Solar panels
• 🔥 Heat pumps
• ⚡ Energy consumption
• 🏭 Any device with S0 pulse output

S0 Pulse Meters

Rating	Pulse Rate	Sources
45A kWh Meter	1000 imp/kWh	Bol.com
40A kWh Meter	2000 imp/kWh	Bol.com
32A kWh Meter	2000 imp/kWh	Amazon
40A kWh Meter	1000 imp/kWh	Amazon

Understanding Pulse Rates:

• 2000 imp/kWh = 0.0005 kWh per pulse (more accurate)
• 1000 imp/kWh = 0.001 kWh per pulse

S0 Connection Diagrams

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📋 Compatible Devices

Water Meters

Check compatibility: GitHub Discussion #57

Confirmed Compatible:

Brand	Model	Location
Elster	V200	NL
Itron	Aquadis+	NL
Sensus	620	NL
Maddalena	CD SD Plus	BE
Actaris	Single-Jet	NL
Zenner	MNK-RP-N	DE
Kamstrup	Multical 21	EU
Diehl	Hydrus	EU

Power Meters (S0 Output)

Check compatibility: GitHub Discussion #250

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🔧 Adjusting Meter Readings

Water Meter

kWh Meter

All Meters

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🔄 Updates

Via ESPHome Dashboard

1. Open ESPHome in Home Assistant
2. Find your S0tool device
3. Click the three dots (⋮)
4. Select “Validate” → “Install”

Latest releases: GitHub Releases

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🐛 Troubleshooting

USB Serial Drivers

If the serial port doesn’t appear, install the appropriate driver:

Chip	Driver
CP2102 (square chip)	Download
CH341	Download
CH340	Download

Common Issues

Device not connecting to Wi-Fi:

• Ensure you’re using 2.4GHz Wi-Fi (5GHz not supported)
• Check SSID and password are correct
• Try holding the boot button during flash

Meter readings not updating:

• Verify sensor is properly aligned with meter
• Check wiring connections
• Ensure 10K resistor is installed correctly

More Help:

• 📖 Full Documentation
• 💬 Discord Community
• 🐛 Report Issues

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🤝 Contributing

We welcome contributions of all kinds! Please see CONTRIBUTING.md for guidelines.

Ways to Contribute

• 🐛 Report bugs via Issues
• 💡 Suggest features or improvements
• 🔧 Submit Pull Requests
• 📝 Improve documentation
• 🌟 Star this repository!

Contributors

This project is made possible by our amazing contributors!

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💖 Support

Enjoying the S0tool? Consider supporting development:

Other ways to support:

• 🌟 Star this repository
• 📢 Share with others
• 💬 Join our Dutch Discord

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📄 License

MIT License

Copyright © 2021 - 2026 Huizebruin.nl / S0tool.nl

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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🙏 Credits

Created by: Wobbe From: Huizebruin.nl & S0tool.nl

Powered by: ESPHome & ESP Web Tools

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