[](https://hackaday.com/2025/10/02/building-a-desk-display-for-time-and-weather-data)
[](https://www.xda-developers.com/super-sleek-esp32-weather-station)
**ESPTimeCast** is a sleek, WiFi-connected LED matrix clock and weather display built on **ESP8266/ESP32** and **MAX7219**.
It combines real-time NTP time sync, live OpenWeatherMap updates, and a modern web-based configuration interface — all in one compact design.
## 📦 3D Printable Case
To help support the project’s development, the official **ESPTimeCast** case design is available as a **paid STL download** (see links below).
If you prefer a free option, there are many compatible **MAX7219 LED matrix enclosures** shared by the community — you can find plenty by searching for “MAX7219 case” on Printables, Cults3D, or similar sites.
## 📰 Press Mentions
ESPTimeCast has been featured on:
- [Hackaday](https://hackaday.com/2025/10/02/building-a-desk-display-for-time-and-weather-data)
- [XDA Developers](https://www.xda-developers.com/super-sleek-esp32-weather-station)
## ✨ Features
- **LED Matrix Display (8x32)** powered by MAX7219, with custom font support
- **Simple Web Interface** for all configuration (WiFi, weather, time zone, display durations, and more)
- **Automatic NTP Sync** with robust status feedback and retries
- **Weather Fetching** from OpenWeatherMap (every 5 minutes, temp/humidity/description)
- **Custom Scroll Messages** - fully persistent until manually cleared via the Web UI
- **Fallback AP Mode** for easy first-time setup or configuration
- **Timezone Selection** from IANA names (DST integrated on backend)
- **Get My Location** button to get your approximate Lat/Long
- **Week Day and Weather Description display** in multiple languages
- **Persistent Config** stored in LittleFS, with backup/restore system
- **Status Animations** for WiFi connection, AP mode, time syncing
- **Advanced Settings** panel with:
- Custom **Primary/Secondary NTP server** input
- Display **Day of the Week** toggle (default is on)
- Display **Blinking Colon** toggle (default is on)
- Show **Date** toggle (default is off)
- **24/12h clock mode** toggle (24-hour default)
- **Imperial Units (°F)** toggle (metric °C defaults)
- Show **Humidity** toggle (display Humidity besides Temperature)
- **Weather description** toggle (displays: heavy rain, scattered clouds, thunderstorm etc.)
- **Flip display** (180 degrees)
- Adjustable display **brightness**
- **Automatic Dimming** based on Sunrise/Sunset from weather API
- **Custom Dimming** select custom dimming hours
- **Countdown** function (Scroll / Dramatic)
- **Optional:** ESPTimeCast supports displaying glucose data from **Nightscout** servers every 5 minutes, alternating with weather information
- **Optional:** Export and Upload settings via `device-ip/export` and `device-ip/upload` endpoints
## 🪛 Wiring - OCT 17 - Important Hardware Update ⚠️ ⚠️ ⚠️
**Pin assignments have been standardized across all Wemos D1 Mini and S2 Mini boards!**
Check your board version and make sure **your sketch matches the new pin layout**, especially note that **`CLK` is now on `D5` (was `D6`)**.
After testing, we found that powering the MAX7219 matrix from the **D1 Mini’s 3.3V pin** can cause **overheating and unstable display behavior**, so we’re now officially powering the display from the **5V USB rail** instead.
This change improves **brightness**, **stability**, and protects the **onboard voltage regulator** from long-term damage.
> **Note:** Pin positions on the header remain the same, but ensure your sketch uses the correct pin definitions.
#### What’s Changing
- **Before:** Display VCC was connected to the **3.3V** pin on the ESP board
- **Now:** Display VCC connects to the **5V** pin (direct from USB power)
- **CLK:** moved from **D6 → D5**
#### Why This Change Is Needed
- Standardized pin assignment across all Wemos D1 Mini and S2 Mini boards
- The **MAX7219** LED matrix is designed for **5V operation**
- The **AMS1117 3.3V regulator** on most D1 Minis has limited current (~800 mA max, often less)
- High-brightness displays (especially green/yellow) can overload it, causing:
- Overheating
- Voltage drop
- Regulator failure (some users saw only **2.4 V** output after damage)
#### Benefits of Using 5V
- Brighter and more stable display output
- Reduced heat load on the ESP board
- Prevents long-term regulator damage
- No level shifters required — **MAX7219 works fine with 3.3V logic signals**
#### Next Steps
- Double-check your board wiring before powering on
- Update your sketch pin definitions if you’re upgrading from an older build
- Reference the diagram below for correct wiring (coming next)
#### 🧩 Board → MAX7219
| D1 Mini (Micro USB) | D1 Mini (USB C) | D1 Mini (ESP 32) | S2 Mini | MAX7219 |
|:-----:|:-----:|:-----:|:-----:|:------|
| GND | GND | GND | GND | GND |
| 5V | 5V/VBUS | 5V/VBUS | 5V/VBUS | VCC |
| D5 | 14 | 18 | 7 | CLK |
| D7 | 13 | 23 | 11 | CS |
| D8 | 15 | 5 | 12 | DIN |
> **Tip:** Always double-check that VCC (5V), GND, and DIN/CS/CLK match your MAX7219 module’s pin order — different modules sometimes label them differently.
## 🌐 Web UI & Configuration
The built-in web interface provides full configuration for:
- **WiFi settings** (SSID & Password)
- **Weather settings** (OpenWeatherMap API key, City, Country, Coordinates)
- **Time zone** (will auto-populate if TZ is found)
- **Day of the Week and Weather Description** languages
- **Display durations** for clock and weather (milliseconds)
- **Custom Scroll Text** - set a persistent scrolling message on the display directly from the Web UI
- **Advanced Settings** (see below)
## First-time Setup / AP Mode
1. Power on the device. If WiFi fails, it auto-starts in AP mode:
- **SSID:** `ESPTimeCast`
- **Password:** `12345678`
- Captive portal should open automatically, if it doesn't open `http://192.168.4.1` or `http://setup.esp` in your browser.
2. Set your WiFi and all other options.
3. Click **Save Setting** – the device saves config, reboots, and connects.
4. The device shows its local IP address after boot so you can login again for setting changes
> External links and the "Get My Location" button require internet access.
They won't work while the device is in AP Mode - connect to WiFi first.
## UI Example:
## ⚙️ Advanced Settings
Click the **cog icon** next to “Advanced Settings” in the Web UI to reveal extra configuration options.
**Available advanced settings:**
- **Primary NTP Server**: Override the default NTP server (e.g. `pool.ntp.org`)
- **Secondary NTP Server**: Fallback NTP server (e.g. `time.nist.gov`)
- **Day of the Week**: Display Day of the Week in the desired language
- **Blinking Colon** toggle (default is on)
- **Show Date** (default is off, duration is the same as weather duration)
- **24/12h Clock**: Switch between 24-hour and 12-hour time formats (24-hour default)
- **Imperial Units (°F)** toggle (metric °C defaults)
- **Humidity**: Display Humidity besides Temperature
- **Weather description** toggle (display weather description in the selected language for 3 seconds or scrolls once if description is too long)
- **Flip Display**: Invert the display vertically/horizontally
- **Brightness**: Off - 0 (dim) to 15 (bright)
- **Automatic Dimming Feature** base on Sunrise/Sunset from weather API
- **Custom Dimming Feature**: Start time, end time and desired brightness selection
- **Countdown** function, set a countdown to your favorite/next event, 2 modes: Scroll/Dramatic!
>Non-English characters converted to their closest English alphabet.
>For Esperanto, Irish, and Swahili, weather description translations are not available. Japanese translations exist, but since the device cannot display all Japanese characters, English will be used in all these cases.
> **Tip:** Don't forget to press the save button to keep your settings
## 📝 Configuration Notes
- **OpenWeatherMap API Key:**
- [Make an account here](https://home.openweathermap.org/users/sign_up)
- [Check your API key here](https://home.openweathermap.org/api_keys)
- **City Name:** e.g. `Tokyo`, `London`, etc.
- **Country Code:** 2-letter code (e.g., `JP`, `GB`)
- **ZIP Code:** Enter your ZIP code in the city field and US in the country field (US only)
- **Latitude and Longitude** You can enter coordinates in the city field (lat.) and country field (long.)
- **Time Zone:** Select from IANA zones (e.g., `America/New_York`, handles DST automatically)
## 🚀 Getting Started
This guide will walk you through setting up your environment and uploading the **ESPTimeCast** project to your **ESP8266** or **ESP32** board. Please follow the instructions carefully for your specific board type.
#### ⚙️ ESP8266 Setup
Follow these steps to prepare your Arduino IDE for ESP8266 development:
1. **Install ESP8266 Board Package:**
* Open `File > Preferences` in Arduino IDE.
* Add `http://arduino.esp8266.com/stable/package_esp8266com_index.json` to "Additional Boards Manager URLs."
* Go to `Tools > Board > Boards Manager...`. Search for `esp8266` by `ESP8266 Community` and click "Install".
2. **Select Your Board:**
* Go to `Tools > Board` and select your specific board, e.g., **Wemos D1 Mini** (or your ESP8266 variant).
3. **Configure Flash Size:**
* Under `Tools`, select `Flash Size "4MB FS:2MB OTA:~1019KB"`. This ensures enough space for the sketch and LittleFS data.
4. **Install Libraries:**
* Go to `Sketch > Include Library > Manage Libraries...` and install the following:
* `ArduinoJson` by Benoit Blanchon
* `MD_Parola` by majicDesigns (this will typically also install its dependency: `MD_MAX72xx`)
* `ESPAsyncTCP` by ESP32Async
* `ESPAsyncWebServer` by ESP32Async
**⚠️ ESP8266 Library Compatibility Notice**
Due to internal changes in **ESPAsyncWebServer 3.9.0**, large files served from SPIFFS/LittleFS may fail to load on ESP8266 (blank page).
Version **3.8.1** is currently the most stable release for ESP8266, and is recommended for this project.
Install version **3.8.1** manually:
* Arduino IDE → Tools → Manage Libraries
* Search: ESPAsyncWebServer
* Install version 3.8.1
>Future versions may fix this, but for now 3.8.1 ensures full compatibility.
#### ⚙️ ESP32 Setup
Follow these steps to prepare your Arduino IDE for ESP32 development:
1. **Install ESP32 Board Package:**
* Go to `Tools > Board > Boards Manager...`. Search for `esp32` by `Espressif Systems` and click "Install".
2. **Select Your Board:**
* Go to `Tools > Board` and select your specific board, e.g., **LOLIN S2 Mini** (or your ESP32 variant).
3. **Configure Partition Scheme:**
* Under `Tools`, select `Partition Scheme "No OTA (2MB APP/2MB SPIFFS)"`. This ensures enough space for the sketch and LittleFS data.
4. **Install Libraries:**
* Go to `Sketch > Include Library > Manage Libraries...` and install the following:
* `ArduinoJson` by Benoit Blanchon
* `MD_Parola` by majicDesigns (this will typically also install its dependency: `MD_MAX72xx`)
* `AsyncTCP` by ESP32Async
* `ESPAsyncWebServer` by ESP32Async
#### ⬆️ Uploading the Code and Data
Once your IDE is ready:
1. **Open the Project Folder**
* **ESP8266:** Open the `ESPTimeCast_ESP8266` folder and open `ESPTimeCast_ESP8266.ino`.
* **ESP32:** Open the `ESPTimeCast_ESP32` folder and open `ESPTimeCast_ESP32.ino`.
2. **Upload the Sketch**
* Click the **Upload** button (right arrow icon) in the Arduino IDE toolbar. This will compile and upload the sketch to your board.
* **No separate LittleFS upload is needed.** All web UI files are embedded in the sketch.
**⚠️ Note for existing users:** If you have previously uploaded /data via LittleFS, you can safely skip that step now — the device will manage config files internally.
## 🏠 ESPTimeCast Home Assistant Integration
This guide explains how to integrate **ESPTimeCast** with **Home Assistant** to send custom messages to your LED display.
#### 🧠 Overview
ESPTimeCast exposes a REST API endpoint that lets you send **scrolling messages** to the display from either **Home Assistant** or the built-in **Web UI**.
- **Web UI messages** are **persistent** — they remain active until manually cleared via the Web UI.
- **Home Assistant messages** are **temporary overrides** - they appear immediately but do not modify the saved Web UI message.
- **When cleared from HA** - the display will resume showing the previously saved UI message on the next update loop.
#### 🔗 Endpoint
```
POST http:///set_custom_message
```
#### 📝 Parameters
| Parameter | Type | Required | Description |
|------------|------|-----------|-------------|
| `message` | string | Yes | Message text to display. Send an empty string (`""`) to clear messages. |
| `speed` | integer | Optional | Scrolling speed (range **10–200**). Lower values = **faster** scroll. |
#### 💡 Behavior
| Source | Behavior | Notes |
|---------|-----------|-------|
| **Home Assistant** | Displays message temporarily (until next mode rotation or clear). | Restores any saved Web UI message afterward. |
| **Web UI** | Displays message persistently until manually cleared. | Acts as a permanent banner or ticker. |
| **Clear command from Web UI** | Clears *all* messages (HA + UI). | Use this to reset the display completely. |
| **Clear command from Home Assistant** | Clears only the temporary HA message. | UI message will reappear if one was saved. |
#### ⚙️ Example Automations
#### 1. Send a Temporary HA Message
```yaml
alias: Notify Door Open on ESPTimeCast
trigger:
- platform: state
entity_id: binary_sensor.front_door
to: "on"
action:
- service: rest_command.esptimecast_message
data:
message: "DOOR OPEN"
speed: 60 # lower = faster
```
#### 2. Clear the Message
```yaml
alias: Clear ESPTimeCast Message
trigger:
- platform: state
entity_id: binary_sensor.front_door
to: "off"
action:
- service: rest_command.esptimecast_message
data:
message: ""
```
#### 🧩 Example `rest_command` Configuration
Add this to your `configuration.yaml`:
```yaml
rest_command:
esptimecast_message:
url: "http:///set_custom_message"
method: POST
content_type: "application/x-www-form-urlencoded"
payload: "message={{ message }}&speed={{ speed | default(85) }}"
```
Then restart Home Assistant.
#### ⚡ Quick Test via curl
You can quickly test sending a message to your ESPTimeCast display using `curl` from any computer on the same network:
```
curl -X POST -d "message=HELLO WORLD&speed=50" "http:///set_custom_message"
```
> Replace with the IP of your ESPTimeCast device.
> The message parameter is your text to display.
> The optional speed parameter controls the scroll speed (10–200, lower = faster).
#### 🧾 Notes
- Only **A–Z, 0–9**, spaces, and simple punctuation (`: ! ' - . , _ + % / ?`) are allowed.
- All text is automatically converted to **uppercase**.
- Lower scroll speed values make the message **scroll faster**.
- Custom Message scroll speed can be changed via this endpoint.
#### ✅ Example Use Cases
- Temporary alerts like **DOOR OPEN**, **RAIN STARTING**, or **MAIL DELIVERED**.
- Persistent ticker messages from the Web UI like **WELCOME HOME** or **ESPTIMECAST LIVE**.
- Combine both: Web UI for a base banner, and HA for transient automation messages.
## 🧩 Hidden & Advanced Features
ESPTimeCast includes a few optional “power-user” features that aren’t visible in the main interface but can be accessed directly from your browser. These are intended for advanced users who want more control or integration.
#### ⚙️ /factory_reset
Erases all saved configuration data, Wi-Fi credentials, and uptime history.
Used to restore the device to its original state. Only available in **AP mode**.
#### 💾 /export
Downloads your current configuration (`config.json`) directly from the device.
This is useful for creating backups or migrating settings between devices.
**Example:**
```
http://your-device-ip/export
```
The file will download automatically with your saved WiFi credentials (safely masked for security) and all other settings.
#### 📂 /upload
Lets you manually upload a configuration file (`config.json`) to the device.
Perfect for restoring a backup or quickly switching between setups.
**Usage:**
1. Go to
```
http://your-device-ip/upload
```
2. Select your edited or backup `config.json` file.
3. The device will confirm the upload and automatically reboot with the new configuration.
> *Tip:* You can export → edit the file on your computer → re-upload to test new settings without using the web interface.
#### ⚕️ Nightscout Integration
ESPTimeCast supports displaying glucose data from **Nightscout** servers alongside weather information.
When the secondary NTP/URL field (`ntpServer2`) contains a valid Nightscout API endpoint for example:
```
https://your-cgm-server/api/v1/entries/current.json?token=xxxxxxxxxxxxx
```
the device automatically enables **Glucose Display Mode**.
In this mode:
- The device fetches glucose data every 5 minutes.
- Glucose value and trend direction are displayed alternately with time and weather.
- The display duration for Nightscout data is the same as the weather display duration.
- Weather data continues to display normally.
- Debug logs confirm updates and Nightscout responses in the Serial Monitor.
#### ⚠️ Notes
- These features are optional and hidden from the main interface to avoid clutter.
- `/upload` and `/export` are intentionally unlinked from the UI to prevent accidental access.
- Always verify your WiFi credentials and tokens before uploading edited configurations.
## 📺 Display Behavior
**ESPTimeCast** automatically switches between two display modes: Clock and Weather.
If "Show Weather Description" is enabled, a third mode (Description) will display with a duration of 3 seconds, if the description is too long to fit on the display the description will scroll from right to left once.
What you see on the LED matrix depends on whether the device has successfully fetched the current time (via NTP) and weather (via OpenWeatherMap).
The following table summarizes what will appear on the display in each scenario:
| Display Mode | 🕒 NTP Time | 🌦️ Weather Data | 📺 Display Output |
|:------------:|:----------:|:--------------:|:--------------------------------------------|
| **Clock** | ✅ Yes | — | 🗓️ Day Icon + ⏰ Time (e.g. `@ 14:53`) |
| **Clock** | ❌ No | — | `! NTP` (NTP sync failed) |
| **Weather** | — | ✅ Yes | 🌡️ Temperature (e.g. `23ºC`) |
| **Weather** | ✅ Yes | ❌ No | 🗓️ Day Icon + ⏰ Time (e.g. `@ 14:53`) |
| **Weather** | ❌ No | ❌ No | `! TEMP` (no weather or time data) |
#### How it works:
- The display automatically alternates between **Clock** and **Weather** modes (the duration for each is configurable).
- If "Show Weather Description" is enabled a third mode **Description** will display after the **Weather** display with a duration of 3 seconds.
- In **Clock** mode, if NTP time is available, you’ll see the current time plus a unique day-of-week icon. If NTP is not available, you'll see `! NTP`.
- In **Weather** mode, if weather is available, you’ll see the temperature (like `23ºC`). If weather is not available but time is, it falls back to showing the clock. If neither is available, you’ll see `! TEMP`.
- All status/error messages (`! NTP`, `! TEMP`) are big icons shown on the display.
**Legend:**
- 🗓️ **Day Icon**: Custom symbol for day of week (`@`, `=`, etc.)
- ⏰ **Time**: Current time (HH:MM)
- 🌡️ **Temperature**: Weather from OpenWeatherMap
- ✅ **Yes**: Data available
- ❌ **No**: Data not available
- — : Value does not affect this mode
## Support this project
ESPTimeCast is an open-source passion project that blends art, engineering, and information display.
If you enjoy this project, please consider supporting my work:
[](https://www.paypal.me/officialuphoto)
[](https://github.com/sponsors/mfactory-osaka)