ESP32 Constellation Finder (with a Web App)

Do you love looking at the night sky but can’t find constellations easily? With this project, you can build your own Constellation Finder using an ESP32 microcontroller and a small OLED screen.

This gadget will:

1. Show you which constellations are up right now.
2. Tell you the direction (north, south, east, west) and height in the sky.
3. Give a rise and set time for each constellation.
4. Provide “Steer Me” hints like “turn left 12°, look up 8°”.
5. Show a webpage on your phone so you can control it remotely.
6. Use LEDs to quickly show whether the constellation is visible.

Firstly educational use of this project :

For children: Fun way to learn astronomy and directions.

For schools: Combines electronics, programming, and science.

For telescope users: No more guessing — always know when and where to look.

For hobbyists: Expand it with new features like planets or motor control.

So It’s fun for kids, students, hobbyists, and telescope users. Let’s get started!

Supplies

You’ll need:

1 × ESP32 dev board (NodeMCU ESP32, WROOM, etc.)

1 × 0.96" OLED Display (SSD1306, I²C version)

2 × Push buttons

2 × LEDs (red + green)

2 × Resistors (220Ω each)

1 × Optional buzzer

Breadboard or perfboard + jumper wires

USB cable for programming and power

Power bank (for portable use)

---- You can later make a small box/case to carry it like a gadget.

Step 1: Wiring the Circuit

OLED VCC-----> 3.3V or 5v (for some boards)

OLED GND --------> GND

OLED SDA --------> GPIO 21

OLED SCL --------> GPIO 22

NEXT Button --------> GPIO 32

AUTO Button --------> GPIO 33

Green LED --------> GPIO 25

Red LED. --------> GPIO 26

Buzzer + --------> GPIO 27

Buzzer – ------> GND

The OLED shows constellation info.

Buttons let you change constellation or toggle auto mode.

LEDs show green if visible, red if below horizon.

Step 2: Code

download code from here:

Step 3: Install the Software

1) Install Arduino IDE from arduino.cc.

2) Add ESP32 support:

1. File → Preferences → Additional Board URLs → paste:

"https://dl.espressif.com/dl/package_esp32_index.json"

1. Then go to Tools → Board Manager → search for ESP32 → install.

3) Install these libraries:

1. Adafruit SSD1306
2. Adafruit GFX
3. Preferences (already included)
4. WiFi (already included)

--> And go to tools and select board and select (esp32) your board type like mine was esp32 dev module

Step 4: Edit the Code (that I Given)

Open the provided code in Arduino IDE.

Look for this part and add your Wi-Fi name and password:

const char* ssid = "YOUR_WIFI_NAME";

const char* password = "YOUR_WIFI_PASSWORD";

do it like

const char* ssid = "HomeWiFi";

const char* password = "12345678";

you can use your mobile hotspot also ----------

--->. 1 thing to remember that you can only open the site in the mobile or laptop that connected with same wifi given in code

Step 5: Connect Via Webpage

1. Open the Serial Monitor in Arduino IDE.
2. It will show the ESP32’s IP address. (like : 172.xx.xx.xx)
3. Type that IP into your phone browser.

You’ll see a webpage with constellation info and buttons to: (as shown in my pics i shared)

1. Next constellation
2. Toggle auto mode
3. Enter your heading (for steer-me hints)

Step 6: How to Use the Device

Turn it on at night.

OLED shows:

1. Constellation name
2. Azimuth (direction like 274° W)
3. Elevation (height in sky)
4. Visible / Below Horizon
5. Set time countdown
6. “Steer Me” hints

Press NEXT to change constellation.

Press AUTO to let it cycle every 10 seconds.

Use LEDs:

1. Green = visible
2. Red = below horizon

Use web UI on your phone for easy control.

Step 7: Make It Portable

Mount parts in a 3D-printed or acrylic box.

Power with a USB power bank.

Take it outside like a real gadget.

Optionally, mount on a telescope to help point to constellations.

Step 8: Upgrades You Can Try

1. Add a laser pointer that points at the constellation.
2. Link with a motorized telescope mount.
3. Add a light sensor so it only says “VISIBLE” at night.
4. Display planets and deep-sky objects.

Step 9: So at Last

You’ve built a DIY Constellation Finder that combines astronomy, coding, and electronics. Unlike a phone app, this is your own hardware, customizable, portable, and fun.

It’s a learning tool for kids, a helper for stargazers, and a proud maker project that you can show off in contests!