Experimental DIY Digital Level

Description:

A compact, experimental DIY digital level built around an ESP32-C3, MPU-6050, and a 0.96" OLED display. It provides real-time pitch and roll measurements with a clean bubble-style interface, multiple display modes, and adjustable tolerance. The device includes onboard calibration, battery monitoring, and a simple 3-button interface, all designed to fit into a small 3D-printed enclosure.

This project is intended for makers who want a customizable, portable digital level and a fun electronics build.

Features:

• Real-time bubble level for instant alignment feedback
• Multiple display modes (bubble, large pitch, large roll, single axis)
• Screen color inversion when within tolerance for clear visual feedback
• Smooth and stable readings using Kalman filtering and averaging
• Zero button for calibration on any surface
• Adjustable tolerance (±0.5° to ±5°)
• Freeze/hold function to lock readings
• Battery voltage indicator
• Auto sleep after 30 seconds of inactivity
• Splash screen with button reference
• Left Button: Tolerance, Middle Button: Calibrate, Left Button: Modes
• The USB-C port is only for uploading code and serial communication. It is not for charging the batteries.

Parts List:

Microcontroller: Lolin ESP32-C3 Mini

IMU: GY-521 MPU-6050 (6-axis) ()

Display: 0.96" OLED SSD1306, 128×64, I2C ()

Voltage sensor: DC 0–25V voltage sensor module

3x Tactile buttons: 6×6mm 4-pin tactile push buttons

Simple On-Off Switch

4 Slot AA Battery pack: I used four 1.2V rechargeable batteries from Ikea → If you want to build this, make sure that your batteries don't exceed 5V in total

M3 screws and threaded inserts

Links suggestions (from Aliexpress):

Microcontroller: https://de.aliexpress.com/item/1005004740051202.html?spm=a2g0o.productlist.main.13.67c9eCpreCprux&algo_pvid=a82db511-a799-47f7-906c-ea14bbf0647a&pdp_ext_f=%7B%22order%22%3A%221275%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005004740051202%7C_p_origin_prod%3A

Display: https://de.aliexpress.com/item/1005006141235306.html?spm=a2g0o.productlist.main.1.4dff6752CTsnKO&algo_pvid=a49af0b4-37f3-42b1-b0ce-23efaf13660e&pdp_ext_f=%7B%22order%22%3A%2219897%22%2C%22spu_best_type%22%3A%22price%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005006141235306%7C_p_origin_prod%3A

IMU: https://de.aliexpress.com/item/1005007989748804.html?spm=a2g0o.productlist.main.1.3af75b26XydamT&algo_pvid=73531846-37d6-4437-9d25-ca1aee29f528&pdp_ext_f=%7B%22order%22%3A%221555%22%2C%22spu_best_type%22%3A%22price%22%2C%22eval%22%3A%221%22%2C%22fromPage%22%3A%22search%22%7D&utparam-url=scene%3Asearch%7Cquery_from%3A%7Cx_object_id%3A1005007989748804%7C_p_origin_prod%3A

Tips:

• Use hot glue to secure components
• Print button caps in TPU
• Use "The Perfect TPU Profile" by AllFor3D for best button cap results

Pin Reference:

Wiring Diagram:

ESP32-C3 Mini
┌─────────────────────────────┐
│  3V3     ────────────────────────┼──► IMU VCC
│                   └─────────────────────┼──► OLED VDD

│                                                                               │
│  GND   ────────────────────────┼──► IMU GND
│                   ├─────────────────────┼──► OLED GND
│                   ├─────────────────────┼──► BTN other legs
│                   └─────────────────────┼──► Voltage sensor V-
│                                                                               │
│  GPIO 8  (SDA) ───────────────────┼──► IMU SDA
│                           └──────────────────┼──► OLED SDA

│                                                                               │
│  GPIO 10 (SCL)      ─────────────────┼──► IMU SCL
│                        └───────────────────┼──► OLED SCK
│                                                                               │
│  GPIO 1  ───────────────────────┼──► Voltage sensor S
│  GPIO 4  ───────────────────────┼──► MODE button
│  GPIO 3  ───────────────────────┼──► CAL button
│  GPIO 2  ───────────────────────┼──► TOL button

│                                                                               │

│  VBUS  ───────────────────────   ┼──► Battery +
└─────────────────────────────┘

IMU (GY-521)                OLED (SSD1306)
┌─────────┐          ┌─────────┐
│ VCC──3V3    │          │ VDD─3V3      │
│ GND──GND │          │ GND──GND │
│ SCL──G10    │          │ SCK──G10    │
│ SDA──G8     │          │ SDA──G8      │
│ XDA──NC    │           └─────────┘
│ XCL──NC     │
│ ADO──NC   │
│ INT──NC     │
└────────┘
NC = Not connected

G = GPIO

Voltage Sensor Module                    Battery
┌──────────────┐              ┌────────┐
│ V+ (screw)   ──────┼─────┼───   BAT+ │
│ V- (screw)    ──────┼─ GND ┼───  BAT-   │
│ S  ──── G1   ─────│             └────────┘
└──────────────┘

Buttons (all identical wiring)
 GPIO 4 ──┤MODE├── GND
 GPIO 3 ──┤CAL ├── GND
 GPIO 2 ──┤TOL ├── GND

 Use opposite legs of the 4-pin button
 (left leg → GPIO, right leg → GND) → i recommend to wire the GNDs of the Buttons in series to save space

ON-OFF Switch

Connect Switch to the Battery's positive pole and the ESP32 VBUS/Voltage Sensor + Screw Terminal

Code (On GitHub):

https://github.com/ruidan-web/esp32-digital-level/tree/main

Project Status:

This is an experimental DIY project. Accuracy may vary depending on calibration, assembly, and component quality

Disclaimer:

This project is provided for educational and experimental DIY purposes only. The design, documentation, wiring diagrams, and software are provided as-is, without any guarantees of accuracy, completeness, or safety.

By building or using this project, you agree that you do so at your own risk. I am not responsible for any damage, injury, malfunction, data loss, incorrect measurements, or other issues that may occur from the use, assembly, or modification of this project.