--- title: "2nd Gen Arduino Hot Water Solar Collector Controller" url: "https://maker.wiznet.io/irina/projects/2nd-gen-arduino-hot-water-solar-collector-controller-1/" markdown_url: "https://maker.wiznet.io/irina/projects/2nd-gen-arduino-hot-water-solar-collector-controller-1/md" type: "UCC: User Created Content" author: "Thorigol" author_url: "https://www.instructables.com/2nd-Gen-Arduino-Hot-Water-Solar-Collector-Controll" editor: "WIZnet" editor_url: "https://maker.wiznet.io/" original_author: "Thorigol" original_url: "https://www.instructables.com/2nd-Gen-Arduino-Hot-Water-Solar-Collector-Controll" published: "2025-12-11" language: "en" likes: 0 views: 368 comments: 0 source: "WIZnet Makers (https://maker.wiznet.io/)" --- # 2nd Gen Arduino Hot Water Solar Collector Controller > A second-generation Arduino solar hot water controller using DS18B20 sensors, relay-based pump control, and an Ethernet Shield for remote monitoring and data lo Original author: Thorigol (source: https://www.instructables.com/2nd-Gen-Arduino-Hot-Water-Solar-Collector-Controll) ## Article ![](https://maker.wiznet.io/upload/ckeditor5/201742316%5F1765466663%2Epng) ## πŸ‘€AUTHOR **Debe ** A DIY maker passionate about renewable energy, automation, and open-source hardware. This project reflects hands-on experimentation, iterative improvement, and real-world solar-thermal system optimization. πŸ”— Original Project: --- ## πŸ“Œ BACKGROUND & MOTIVATION After decades of operating this large solar thermal system, the creator understood its biggest challenge: **accurate temperature measurement at many points** and **intelligent pump coordination**. Existing Arduino solar controllers were simple and functional, but lacked: - IoT monitoring - multi-sensor compatibility - advanced pump logic - web-based control - high-temperature sensor support - freeze and overheat safety automation A modernized controller needed to handle **PT1000 RTDs**, legacy **10k thermistors**, and **DS18B20 digital sensors**β€”because the system contained a mix of old and new hardware. The system also requires control of three separate pump circuits: 1. **Collector pump** (Panel β†’ Storage) 2. **Domestic hot water extraction pump** 3. **Home heating extraction pump** To upgrade this complex infrastructure, the author defined clear goals: #### Required Inputs - Read **PT1000 RTD** sensors inside solar panels - Read **10k thermistors** already installed in the tanks - Read **DS18B20 digital sensors** for general temperature points - Allow any sensor to be assigned to any function #### Required Outputs & Logic - Control **DHW extraction pump** - Control **home heating pump** - Freeze protection & maximum temperature shutoff - LCD-based UI - Manual override buttons - Two-stage **lead/lag pump logic** for higher solar efficiency - **Publish temperatures & pump status via Ethernet** - Provide full pump control via the webpage This second-generation controller now achieves nearly all of these goals and operates reliably. ## 🎯PROJECT DESCRIPTION This project implements a **second-generation Arduino-based solar hot water controller**, designed to automatically manage heat collection, temperature sensing, pump activation, data display, and system safety. ![](https://maker.wiznet.io/upload/ckeditor5/201742316%5F1765465404%2Epng) It improves upon the first-generation model by adding: - Measure collector & tank temperatures - Decide when to run the circulation pump - Display data on LCD - Store settings in EEPROM - **Send operating status to a remote dashboard via Ethernet** The Ethernet Shield makes the system significantly more powerful, enabling: - Home network integration - Browser-based viewing of system temperature - Remote pump status monitoring - Data recording for system optimization ![](https://maker.wiznet.io/upload/ckeditor5/201742316%5F1765465360%2Epng) The controller monitors temperature differences between the **solar collector** and the **water storage tank**, then activates the circulation pump when heat gain is optimalβ€”maximizing efficiency and preventing overheating or heat loss. ![](https://maker.wiznet.io/upload/ckeditor5/201742316%5F1765465307%2Epng) --- ## 🧩COMPONENTS ### 🧠 Hardware - **Arduino UNO / Nano** - **Arduino Ethernet Shield (W5100 or W5500-based)** - Temperature sensors (Collector + Tank) - **PT1000 RTD** (high-temp solar panels) - **10k thermistors** (legacy storage tank sensors) - **DS18B20 digital sensors** - Relay or SSR for pump control - 20x4 LCD (IΒ²C optional) - EEPROM (built-in) - Manual switches / LEDs - Outdoor-rated wiring and enclosure ## 🧰 SYSTEM OVERVIEW ```css Solar Collector Temp ----┐ β”‚ Tank Temp Sensor --------β”Ό--> Arduino Controller β”‚ β”‚ β”‚ β”‚ Relay Output β”‚ ---> Pump ON/OFF β”‚ LCD Display β”‚ ---> Status UI β”‚ Ethernet β”‚ ---> Web Monitoring Shield ``` Arduino handles control logic, while the **Ethernet Shield** hosts a simple web interface that: - Displays all temperatures - Shows pump statuses - Allows remote pump activation/deactivation ## βœ” KEY FEATURES #### πŸ”Ή **Smart Pump Control** - Calculates Ξ”T (collector–tank difference) - Activates pump only when energy gain is positive - Prevents reverse heat flow at night ### πŸ”Ή **Ethernet-Based Monitoring** With the Ethernet Shield, users can: - View temperatures via web browser - Check pump status remotely - Use tools like Excel, Home Assistant, or Grafana for tracking - Log data for system maintenance and optimization ![](https://maker.wiznet.io/upload/ckeditor5/201742316%5F1765466065%2Epng)n ### πŸ”Ή **Clear Local UI** LCD shows: - Collector temperature - Tank temperature - Pump status - System mode (Auto/Manual) - Useful for maintenance and direct local control. ### πŸ”Ή **Improved Energy Efficiency** The second-generation design reduces standby loss and optimizes solar gain. --- ## πŸ§ͺUSE CASES - Residential solar water heating - Off-grid home automation - Renewable energy experimentation - IoT-enabled home energy management - Long-term performance monitoring - Thermal system optimization --- ## 🧠 ENGINEERING INSIGHTS - The use of DS18B20 sensors enables stable, waterproof temperature measurement. - Ethernet Shield integration simplifies IoT functionality without needing Wi-Fi modules. - Browser-based dashboard enables real-time visualization of solar heat collection efficiency. - EEPROM-based configuration ensures persistent user settings. - Relay isolation enhances safety for pump control. If upgraded with W5500, reliability and network performance improve further. --- ## πŸ‘€AUTHOR **Debe ** μž¬μƒ μ—λ„ˆμ§€, μžλ™ν™”, μ˜€ν”ˆ μ†ŒμŠ€ ν•˜λ“œμ›¨μ–΄μ— 열정을 가진 DIY μ œμž‘μž. 이 ν”„λ‘œμ νŠΈλŠ” ν˜„μž₯ μ‹€ν—˜, 반볡적인 κ°œμ„ , 그리고 μ‹€μ œ νƒœμ–‘μ—΄ μ‹œμŠ€ν…œ μ΅œμ ν™”λ₯Ό λ°˜μ˜ν•©λ‹ˆλ‹€ πŸ”—μ›λ³Έ ν”„λ‘œμ νŠΈ: --- ## πŸ“Œ λ°°κ²½ 및 동기 μˆ˜μ‹­ λ…„κ°„ λŒ€ν˜• νƒœμ–‘μ—΄ μ‹œμŠ€ν…œμ„ μš΄μ˜ν•˜λ©΄μ„œ, μ œμž‘μžλŠ” κ°€μž₯ 큰 어렀움이 **λ§Žμ€ μ§€μ μ˜ μ •ν™•ν•œ μ˜¨λ„ μΈ‘μ •κ³Ό 지λŠ₯적인 νŽŒν”„ μ‘°μ •**μ΄λΌλŠ” 것을 μ•Œκ²Œ λ˜μ—ˆμŠ΅λ‹ˆλ‹€. 기쑴의 Arduino νƒœμ–‘κ΄‘ μ»¨νŠΈλ‘€λŸ¬λŠ” κ°„λ‹¨ν•˜κ³  κΈ°λŠ₯μ μ΄μ—ˆμ§€λ§Œ, λ‹€μŒκ³Ό 같은 κΈ°λŠ₯이 λΆ€μ‘±ν–ˆμŠ΅λ‹ˆλ‹€: - IoT λͺ¨λ‹ˆν„°λ§ - 닀쀑 μ„Όμ„œ ν˜Έν™˜μ„± - κ³ κΈ‰ νŽŒν”„ 둜직 - μ›Ή 기반 μ œμ–΄ - 고온 μ„Όμ„œ 지원 - λ™νŒŒ 및 κ³Όμ—΄ μ•ˆμ „ μžλ™ν™” ν˜„λŒ€ν™”λœ μ»¨νŠΈλ‘€λŸ¬λŠ” **PT1000 RTD**, 기쑴의 **10k μ„œλ―ΈμŠ€ν„°**, 그리고 **DS18B20 디지털 μ„Όμ„œ**λ₯Ό μ²˜λ¦¬ν•΄μ•Ό ν–ˆμŠ΅λ‹ˆλ‹€. μ™œλƒν•˜λ©΄ μ‹œμŠ€ν…œμ— κΈ°μ‘΄ 및 μ‹ κ·œ ν•˜λ“œμ›¨μ–΄κ°€ ν˜Όμž¬λ˜μ–΄ μžˆμ—ˆκΈ° λ•Œλ¬Έμž…λ‹ˆλ‹€. λ˜ν•œ, 이 μ‹œμŠ€ν…œμ€ μ„Έ 가지 κ°œλ³„ νŽŒν”„ 회둜λ₯Ό μ œμ–΄ν•΄μ•Ό ν•©λ‹ˆλ‹€: - **집열기 νŽŒν”„** (νŒ¨λ„ β†’ μ €μž₯μ†Œ) - κ°€μž₯ μ€‘μš”ν•œ λΆ€λΆ„μž…λ‹ˆλ‹€. 이 μ»¨νŠΈλ‘€λŸ¬λŠ” λ‹¨μˆœνžˆ νƒœμ–‘μ—΄ νŒ¨λ„μ˜ μ˜¨λ„κ°€ μ €μž₯ 탱크보닀 λ†’λ‹€κ³  νŽŒν”„λ₯Ό μΌœλŠ” 데 κ·ΈμΉ˜μ§€ μ•ŠμŠ΅λ‹ˆλ‹€. **μ˜¨λ„μ°¨(Delta T)**에 따라 물의 흐름을 **2단계**둜 μ‘°μ ˆν•©λ‹ˆλ‹€. μ˜¨λ„μ°¨κ°€ 클 λ•ŒλŠ” 'μ„ ν–‰(lead) νŽŒν”„'와 'ν›„ν–‰(lag) νŽŒν”„'λ₯Ό λͺ¨λ‘ μ‚¬μš©ν•˜μ—¬ 물의 μœ λŸ‰μ„ 늘리고, μ˜¨λ„μ°¨κ°€ 쀄어듀면 μœ λŸ‰μ„ 쀄여 μ‹œμŠ€ν…œμ΄ νƒœμ–‘μ—΄μ„ **λ”μš± 효율적으둜** λͺ¨μ„ 수 μžˆλ„λ‘ ν•©λ‹ˆλ‹€. - **μƒν™œ 온수 μΆ”μΆœ νŽŒν”„** - μ €μž₯된 열을 μƒν™œ 온수 곡급을 μœ„ν•΄ μΆ”μΆœν•˜λŠ” νŽŒν”„λ₯Ό μ œμ–΄ν•©λ‹ˆλ‹€. - **κ°€μ • λ‚œλ°© μΆ”μΆœ νŽŒν”„** - **μ§‘μ•ˆ λ‚œλ°©μ„ μœ„ν•΄ μ €μž₯된 열을 μΆ”μΆœν•˜λŠ” νŽŒν”„λ₯Ό μ œμ–΄ν•©λ‹ˆλ‹€.** 이 λͺ¨λ“  μ œμ–΄λŠ” **Arduino Uno** λ³΄λ“œμ™€ **relay shield**, 그리고 **LM335 μ˜¨λ„ μ„Όμ„œ 4개**λ₯Ό 톡해 μ΄λ£¨μ–΄μ§‘λ‹ˆλ‹€. ## 🎯PROJECT DESCRIPTION 이 ν”„λ‘œμ νŠΈλŠ” **2μ„ΈλŒ€ Arduino 기반 νƒœμ–‘μ—΄ 온수 컨트둀러**λ₯Ό κ΅¬ν˜„ν•©λ‹ˆλ‹€. μ΄λŠ” μ—΄ μˆ˜μ§‘, μ˜¨λ„ 감지, νŽŒν”„ ν™œμ„±ν™”, 데이터 ν‘œμ‹œ 및 μ‹œμŠ€ν…œ μ•ˆμ „μ„ μžλ™μœΌλ‘œ κ΄€λ¦¬ν•˜λ„λ‘ μ„€κ³„λ˜μ—ˆμŠ΅λ‹ˆλ‹€. ![](https://maker.wiznet.io/upload/ckeditor5/201742316%5F1765465404%2Epng) μ΄λŠ” 1μ„ΈλŒ€ λͺ¨λΈμ„ λ‹€μŒκ³Ό 같이 κ°œμ„ ν–ˆμŠ΅λ‹ˆλ‹€: - 집열기 및 탱크 μ˜¨λ„ μΈ‘μ • - μˆœν™˜ νŽŒν”„λ₯Ό μž‘λ™ν•  μ‹œμ  κ²°μ • - LCD에 데이터 ν‘œμ‹œ - EEPROM에 μ„€μ • μ €μž₯ - 이더넷을 톡해 원격 λŒ€μ‹œλ³΄λ“œμ— μž‘λ™ μƒνƒœ 전솑 **Ethernet Shield**λŠ” μ‹œμŠ€ν…œμ„ 훨씬 κ°•λ ₯ν•˜κ²Œ λ§Œλ“€μ–΄ λ‹€μŒκ³Ό 같은 κΈ°λŠ₯을 κ°€λŠ₯ν•˜κ²Œ ν•©λ‹ˆλ‹€: - ν™ˆ λ„€νŠΈμ›Œν¬ 톡합 - λΈŒλΌμš°μ € 기반 μ‹œμŠ€ν…œ μ˜¨λ„ 확인 - 원격 νŽŒν”„ μƒνƒœ λͺ¨λ‹ˆν„°λ§ - μ‹œμŠ€ν…œ μ΅œμ ν™”λ₯Ό μœ„ν•œ 데이터 기둝 ![](https://maker.wiznet.io/upload/ckeditor5/201742316%5F1765465360%2Epng) μ»¨νŠΈλ‘€λŸ¬λŠ” νƒœμ–‘μ—΄ 집열기와 λ¬Ό μ €μž₯ 탱크 κ°„μ˜ μ˜¨λ„ 차이λ₯Ό λͺ¨λ‹ˆν„°λ§ν•˜κ³ , μ—΄ νšλ“μ΄ 졜적일 λ•Œ μˆœν™˜ νŽŒν”„λ₯Ό ν™œμ„±ν™”ν•©λ‹ˆλ‹€. 이λ₯Ό 톡해 νš¨μœ¨μ„±μ„ κ·ΉλŒ€ν™”ν•˜κ³  κ³Όμ—΄ λ˜λŠ” μ—΄ 손싀을 λ°©μ§€ν•©λ‹ˆλ‹€. ![](https://maker.wiznet.io/upload/ckeditor5/201742316%5F1765465307%2Epng) --- ## 🧩COMPONENTS ### 🧠 Hardware Arduino UNO / Nano - Arduino 이더넷 μ‰΄λ“œ (W5100 λ˜λŠ” W5500 기반) - **μ˜¨λ„ μ„Όμ„œ** (집열기 + 탱크) - PT1000 RTD (고온 νƒœμ–‘μ—΄ νŒ¨λ„μš©) - 10k μ„œλ―ΈμŠ€ν„° (κΈ°μ‘΄ μ €μž₯ 탱크 μ„Όμ„œμš©) - DS18B20 디지털 μ„Όμ„œ - νŽŒν”„ μ œμ–΄λ₯Ό μœ„ν•œ 릴레이 λ˜λŠ” SSR (Solid State Relay) - 20x4 LCD (IΒ²C μ˜΅μ…˜) - EEPROM (λ‚΄μž₯) - μˆ˜λ™ μŠ€μœ„μΉ˜ / LED - μ‹€μ™Έ λ“±κΈ‰ λ°°μ„  및 μΈν΄λ‘œμ € ## 🧰 SYSTEM OVERVIEW ```css Solar Collector Temp ----┐ β”‚ Tank Temp Sensor --------β”Ό--> Arduino Controller β”‚ β”‚ β”‚ β”‚ Relay Output β”‚ ---> Pump ON/OFF β”‚ LCD Display β”‚ ---> Status UI β”‚ Ethernet β”‚ ---> Web Monitoring Shield ``` ArduinoλŠ” μ œμ–΄ λ‘œμ§μ„ μ²˜λ¦¬ν•˜λ©°, 이더넷 μ‰΄λ“œλŠ” λ‹€μŒμ„ μˆ˜ν–‰ν•˜λŠ” κ°„λ‹¨ν•œ μ›Ή μΈν„°νŽ˜μ΄μŠ€λ₯Ό ν˜ΈμŠ€νŒ…ν•©λ‹ˆλ‹€: - λͺ¨λ“  μ˜¨λ„ ν‘œμ‹œ - νŽŒν”„ μƒνƒœ ν‘œμ‹œ - 원격 νŽŒν”„ ν™œμ„±ν™”/λΉ„ν™œμ„±ν™” ν—ˆμš© ## βœ” KEY FEATURES #### πŸ”Ή **Smart Pump Control** - Ξ”T (집열기 – 탱크 μ˜¨λ„ 차이) 계산 - μ—λ„ˆμ§€ νšλ“μ΄ μ–‘μˆ˜μΌ λ•Œλ§Œ νŽŒν”„ ν™œμ„±ν™” - 밀에 μ—­λ°©ν–₯ μ—΄ 흐름 방지 ### πŸ”Ή **Ethernet-Based Monitoring** 이더넷 μ‰΄λ“œλ₯Ό 톡해 μ‚¬μš©μžλŠ” λ‹€μŒμ„ μˆ˜ν–‰ν•  수 μžˆμŠ΅λ‹ˆλ‹€: - μ›Ή λΈŒλΌμš°μ €λ₯Ό 톡해 μ˜¨λ„ 확인 - μ›κ²©μœΌλ‘œ νŽŒν”„ μƒνƒœ 확인 - 좔적을 μœ„ν•΄ Excel, Home Assistant λ˜λŠ” Grafana와 같은 도ꡬ μ‚¬μš© - μ‹œμŠ€ν…œ μœ μ§€ 보수 및 μ΅œμ ν™”λ₯Ό μœ„ν•œ 데이터 λ‘œκΉ… ![](https://maker.wiznet.io/upload/ckeditor5/201742316%5F1765466065%2Epng)n ### πŸ”Ή **Clear Local UI** LCDλŠ” λ‹€μŒμ„ λ³΄μ—¬μ€λ‹ˆλ‹€: - 집열기 μ˜¨λ„ - 탱크 μ˜¨λ„ - νŽŒν”„ μƒνƒœ - μ‹œμŠ€ν…œ λͺ¨λ“œ (μžλ™/μˆ˜λ™) μœ μ§€ 보수 및 직접적인 둜컬 μ œμ–΄μ— μœ μš©ν•©λ‹ˆλ‹€. ### πŸ”Ή **Improved Energy Efficiency** 2μ„ΈλŒ€ μ„€κ³„λŠ” λŒ€κΈ° 손싀을 쀄이고 νƒœμ–‘μ—΄ νšλ“μ„ μ΅œμ ν™”ν•©λ‹ˆλ‹€.s --- ## 🧠 ENGINEERING INSIGHTS - DS18B20 μ„Όμ„œ μ‚¬μš©μ€ μ•ˆμ •μ μ΄κ³  λ°©μˆ˜λ˜λŠ” μ˜¨λ„ 츑정을 κ°€λŠ₯ν•˜κ²Œ ν•©λ‹ˆλ‹€. - 이더넷 μ‰΄λ“œ 톡합은 Wi-Fi λͺ¨λ“ˆ 없이 IoT κΈ°λŠ₯을 λ‹¨μˆœν™”ν•©λ‹ˆλ‹€. - λΈŒλΌμš°μ € 기반 λŒ€μ‹œλ³΄λ“œλŠ” νƒœμ–‘μ—΄ 집열 효율의 μ‹€μ‹œκ°„ μ‹œκ°ν™”λ₯Ό κ°€λŠ₯ν•˜κ²Œ ν•©λ‹ˆλ‹€. - EEPROM 기반 ꡬ성은 영ꡬ적인 μ‚¬μš©μž 섀정을 보μž₯ν•©λ‹ˆλ‹€. - 릴레이 κ²©λ¦¬λŠ” νŽŒν”„ μ œμ–΄μ˜ μ•ˆμ „μ„±μ„ ν–₯μƒμ‹œν‚΅λ‹ˆλ‹€ W5500으둜 μ—…κ·Έλ ˆμ΄λ“œν•˜λ©΄ μ‹ λ’°μ„±κ³Ό λ„€νŠΈμ›Œν¬ μ„±λŠ₯이 λ”μš± ν–₯μƒλ©λ‹ˆλ‹€. --- Source: https://maker.wiznet.io/irina/projects/2nd-gen-arduino-hot-water-solar-collector-controller-1/