ESP32-C3 Red Alert Monitor
March 23, 2026 · View on GitHub
A standalone ESP32-C3 device that monitors the Israeli Home Front Command (Pikud HaOref) alert API in real time and provides visual feedback via a NeoPixel LED strip and a MAX7219 32×8 dot matrix display — no Home Assistant required.
Features
- Connects to the Pikud HaOref live alert API every 3 seconds
- Filters alerts by city name (configurable via captive portal)
- NeoPixel LED strip changes color based on alert state
- MAX7219 32×8 matrix displays status text
- Captive Portal (WiFiManager) for easy WiFi setup and city configuration — no code changes needed
- City name persisted in flash (survives restarts)
Alert States
| State | LED Color | Matrix Display |
|---|---|---|
| Safe | Green (solid) | SAFE |
| Pre-Alarm | Orange (solid) | PRE ALARM (scrolling) |
| Unsafe | Red (blinking) | UNSAFE (scrolling) |
Photos
Assembled Device — SAFE State
MAX7219 matrix displaying "SAFE" with NeoPixel LEDs above
Enclosure
3D printed case with NeoPixel strip along the bottom edge
Pre-Alarm State
"PRE ALARM" scrolling on the matrix — rockets expected in the area within minutes
Internals
Wiring inside the enclosure — ESP32-C3, NeoPixel strip, and power connections
Hardware
- ESP32-C3 SuperMini (or compatible)
- WS2812B NeoPixel LED strip (12 LEDs)
- MAX7219 32×8 dot matrix display (4× 8×8 modules)
- 3D printed enclosure
Wiring
MAX7219 32×8 Matrix
| MAX7219 Pin | ESP32-C3 GPIO |
|---|---|
| VCC | 5V (USB) |
| GND | GND |
| DIN | GPIO7 |
| CLK | GPIO6 |
| CS | GPIO5 |
NeoPixel WS2812B
| WS2812B Pin | ESP32-C3 GPIO |
|---|---|
| VCC (+5V) | 5V (USB) |
| GND | GND |
| DIN | GPIO2 |
Config Button
| Button Pin | ESP32-C3 |
|---|---|
| Side A | GPIO3 |
| Side B | GND |
No pull-up resistor needed — the internal pull-up is enabled in firmware.
Note: The ESP32-C3 outputs 3.3V logic. MAX7219 at 5V expects a minimum 3.5V high signal — in practice this works, but a level shifter on DIN/CLK/CS can improve reliability.
First-Time Setup
- Power on the device — LED turns blue
- If no WiFi is saved, an access point named
RedAlert-Setupis created - Connect from any phone or computer — the captive portal opens automatically
- Tap Configure WiFi, select your network, enter the password and your city name in Hebrew (e.g.
רמת השרון) - Tap Save — the device connects and begins monitoring
| Portal main screen | WiFi & city configuration |
|---|---|
 |  |
Reconfiguring WiFi or City
A physical config button is connected between GPIO3 and GND.
Hold the button for 3 seconds → the device restarts and opens the RedAlert-Setup portal again, where you can change the WiFi network or city name without reflashing.
The matrix displays CONFIG during this mode.
Configuration
All settings are stored in flash and survive power cycles.
| Parameter | Default | Where to change |
|---|---|---|
| City name | תל אביב | Captive Portal |
| LED count | 12 | NEOPIXEL_COUNT in main.cpp |
| LED brightness | 200 (0–255) | pixel.setBrightness() in main.cpp |
| Matrix brightness | 5 (0–15) | matrix.setIntensity() in main.cpp |
| Poll interval | 3000 ms | CHECK_INTERVAL in main.cpp |
Building & Flashing
This project uses PlatformIO.
# Clone the repo
git clone https://github.com/amir684/esp32c3-red-alert.git
cd esp32c3-red-alert
# Build and upload
pio run --target upload
# Monitor serial output
pio device monitor
Dependencies
| Library | Author |
|---|---|
| WiFiManager | tzapu |
| Adafruit NeoPixel | Adafruit |
| MD_Parola | MajicDesigns |
| MD_MAX72XX | MajicDesigns |
| ArduinoJson | Benoît Blanchon |
Alert API Credit
Live alert data is provided by the Israeli Home Front Command (Pikud HaOref):
- API Endpoint:
https://www.oref.org.il/warningMessages/alert/Alerts.json - For a full Home Assistant integration using the same API, see amitfin/oref_alert
License
Licensed under the Apache License 2.0.