Smart pellet level monitor

An ultrasonic sensor measures how much fuel is left in a pellet boiler. BeginnerWi-FiESP32ESPHomeHC-SR04

Updated November 2026

Illustration of what you build. See the maker’s guide for photos of the real device.

Can I build this?

Estimated costWell under €15 from AliExpress (per the tutorial)
Build timeAbout an hour
DifficultyBeginner
Tools3D printer, computer to flash ESPHome
SolderingNo: Dupont connectors
3D printingYes: the tutorial uses a printable HC-SR04 box

What you need

  • ESP32 board
  • HC-SR04 ultrasonic sensor
  • Dupont jumper wires
  • USB cable
  • Printed case

How it works

Board
ESP32 (ESP32-WROOM-32)
Connects via
Wi-Fi with ESPHome
Made by
SmartHomeScene

Printable caseHC-SR04 box on MakerWorld

Good to know

Build itBuild instructions on SmartHomeSceneFull instructions, wiring and firmware from the maker →

This page summarises the maker’s project; the maker’s own guide is leading. Missing a tool? See In the toolbox. Need a better casing? See 3D printing & enclosures. Keep DIY builds to low voltage (USB or battery).

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