Four screens — tap the left or right edge of the display to switch between them, and tap a widget to change its style (e.g. switch weather forecast, crypto timeframe):
- Main — time (HH:MM), a live seconds indicator (hourglass that fills up, or digits) and a 10-hour weather forecast.
- Big Clock — oversized time plus the current temperature.
- Crypto / Finance — live prices of your chosen assets (crypto, gold, silver, indices…) with the % change; tap to cycle the timeframe (1H … 1Y).
- Egg Timer — a minute/second countdown with Start/Stop and an alarm melody.
More features
- Weather — hourly forecast with icons. No API key needed.
- Finance ticker — live prices via Binance, freely choose your symbols. No API key needed.
- Price alerts — get a sound + a red price when a coin crosses a limit you set (e.g.
BTC>50000). - Alarm clock — set a wake time + weekdays; it plays a melody (tap the screen to stop).
- Egg timer — countdown with selectable alarm tunes.
- Automatic time — synced over the internet (NTP) using your time zone and daylight-saving rules.
- Display comfort — adjustable brightness, night mode (auto-dim during a time window), auto screen-off after inactivity (tap anywhere to wake), and a hold-the-centre gesture to turn the screen off.
- Personalisation — 12/24-hour format, seconds as hourglass or numbers, colours for digits/temperature/crypto, 180° screen flip, and a selectable start screen.
- Easy setup — configured entirely from your phone's browser: no app, no account, no API keys.
- Over-the-air updates — upload new firmware right from the settings page.
- Settings are kept across firmware updates.
A simple, step-by-step guide to get your RetroClock running on the ESP32
You need
- The Cheap Yellow Display (CYD, 2432S028) and a USB data cable (some cables only charge, use a real data cable).
- A computer with Google Chrome, Microsoft Edge, or Opera (desktop). Safari, Firefox and phones cannot flash.
- Your phone (to enter the settings)
- Optional: A small passive piezo buzzer / speaker (for the egg-timer and alarm sound)
- Optional: Case with PiP kickstand (STL file for 3D printing is included)
- Connect a small passive buzzer / speaker between pin GPIO 26 and GND on the CYD's side pin header.
- That's it, without a speaker the clock still works, you just won't hear the timer/alarm.
- Connect the CYD to your computer with the USB cable.
- If nothing lights up, try another USB cable or port (charge-only cables don't work).
- On your computer, open https://seizu.github.io/RetroClockInstaller in Chrome, Edge, or Opera.
- Click Install / Connect.
- In the popup, select the device's serial port (often shown as "USB-SERIAL CH340") and confirm.
- Wait until it finishes and the board restarts, the clock appears on the display.
On the first start there is no WiFi yet, so the device opens its own hotspot. The display shows AP MODE, a WiFi name (SSID) and a web address.
- On your phone, open WiFi settings.
- Connect to the WiFi name shown on the display.
- Password:
RetroClock - Ignore any "no internet" warning, that is normal for a setup hotspot.
- On your phone, open a web browser.
- Type the web address shown on the display
http://10.100.10.1 - The RetroClock settings page opens.
Fill in at least these, then go to step 7:
- WiFi SSID, the name of your home WiFi (must be 2.4 GHz).
- WiFi Password, your home WiFi password.
- Weather Latitude and Weather Longitude, your location, for the weather forecast.
- Posix Timezone String, your local time zone (needed for correct time and automatic daylight-saving).
(Everything else, colours, brightness, night mode, alarm time/sound, start screen, is optional and can be changed anytime.)
- Tap Save.
- Tap Done/Reboot.
- The device restarts, joins your home WiFi, syncs the time automatically and shows the weather.
You don't need to look these up by hand, just ask any AI (e.g. ChatGPT / Claude):
- Location: "What are the latitude and longitude of <your town>?" → enter the two numbers into Latitude / Longitude.
- Time zone: "What is the POSIX TZ string for <your country/city>?" → paste it into Posix Timezone String.
Examples:
| Region | POSIX Timezone String |
|---|---|
| Central Europe (Vienna, Berlin, Paris) | CET-1CEST,M3.5.0/2,M10.5.0/3 |
| UK (London) | GMT0BST,M3.5.0/1,M10.5.0 |
| US East (New York) | EST5EDT,M3.2.0,M11.1.0 |
| US Pacific (Los Angeles) | PST8PDT,M3.2.0,M11.1.0 |
- Normal re-config: while the device is on your WiFi, open its IP address (shown briefly on the display at boot) in a browser.
- Start over / factory reset: hold a finger on the touchscreen while powering the device on. It reopens the setup hotspot and resets all settings to defaults.
Every option on the settings page, with a short note on what it does and how to set it. Colours are palette indices 1–31 (0 = multicolor where allowed). A toggle is an on/off switch. Changes to plain text fields apply after Save + Reboot; toggles and a few live fields (brightness, volume, alarm) apply instantly.
| Setting | What it does / how to use |
|---|---|
| Alarm Active | Live switch: on while any alarm/tone is sounding. Turn off to stop the sound immediately. |
| Initial Screen | Which screen shows after boot: 1 Main, 2 Big Clock, 3 Crypto, 4 Egg Timer. |
| Flip Screen | On rotates the whole display 180° (for upside-down mounting). |
| Clock Digits Color | Colour of the clock digits (1–31). |
| Small Temp Color | Colour of the small temperature on the Main screen (0 = multicolor). |
| Big Temp Color | Colour of the large temperature on the Big Clock screen (1–31). |
| Hourglass BG Color | Background colour of the hourglass seconds indicator (1–31). |
| Hourglass FG Color | Fill colour of the hourglass (1–31). |
| Hourglass | On = seconds as a filling hourglass, off = numeric seconds. |
| 24 Hour Format | On = 24-hour time, off = 12-hour. |
| Weather Latitude | Your location's latitude (−90…90) for the weather forecast. |
| Weather Longitude | Your location's longitude (−180…180) for the weather forecast. |
| Display Off After Seconds | Auto screen-off after inactivity: 0 = never, else 10–300 s (tap to wake). |
| Display Brightness % | Backlight brightness during the day (1–100). |
| Night Brightness % | Brightness inside the night window: 0 = screen off, else 1–100. |
| Night From | Start of the night-dim window (HH:MM). Set From = To to disable night mode. |
| Night To | End of the night-dim window (HH:MM). |
| Volume % | Master volume (0–100) scaling all sounds: alarm, egg-timer, price alert. |
| Alarm Sound | Melody for the wake alarm and egg-timer (1–5). |
| Alarm Time | Wake time for the alarm clock (HH:MM). |
| Alarm Days | 7 digits Mon→Sun, 1 = on (e.g. 1111100 = weekdays). All zeros = alarm off. |
| Crypto Timeframe on Boot | Chart timeframe shown at boot on the Crypto screen (1–9 = 1H…1Y). |
| Crypto Symbol Color | Colour of the asset symbols (0 = multicolor, 1–31). |
| Crypto Price Color | Colour of the prices (0 = multicolor, 1–31). |
| Crypto Date/Time Color | Colour of the date/time on the Crypto screen (0 = multicolor, 1–31). |
| Crypto Assets | Up to 6 assets as Name,BinanceSymbol,Digits;… (e.g. BTC,BTCUSDT,2;GOLD,XAUUSDT,2). |
| Crypto Price Alerts | Alerts as SYM>val or SYM<val, separated by ; (e.g. BTC>50000;ETH<2000). Prefix ? = inactive. |
| Crypto Alert Sound | Melody played when a price alert triggers (1–5). |
| Crypto Alert Color | Price colour while an asset is in alert (1–31). |
| Setting | What it does / how to use |
|---|---|
| WiFi SSID | Name of your home WiFi (2.4 GHz only). |
| WiFi Password | Your home WiFi password (min. 8 characters). |
| WiFi Check Interval | How often the connection is checked and reconnected (5–65535 s). |
| AP Fallback Attempts | After this many failed home-WiFi connects, open the setup hotspot. 0 = never. |
| AP Mode | On = run only as its own hotspot (no home WiFi). Disables the Static-IP option. |
| AP WiFi Password | Password of the device's own hotspot (min. 8 characters). |
| AP Channel | WiFi channel of the hotspot (1–13). |
| Static IP | On = use the fixed address below, off = automatic (DHCP). Enables the 5 fields below. |
| IP Address | Device's fixed IPv4 address (only used when Static IP is on). |
| Subnetmask | Network subnet mask (e.g. 255.255.255.0). |
| Gateway Address | Your router's IP address. |
| DNS Server Address 1 | Primary DNS server (e.g. 1.1.1.1). |
| DNS Server Address 2 | Secondary DNS server (e.g. 1.0.0.1). |
| Setting | What it does / how to use |
|---|---|
| WebPrefs Login | On = require a username + password to open this settings page. Enables the two fields below. |
| WebPrefs User | Username for the settings-page login. |
| WebPrefs Password | Password for the settings-page login. |
| Setting | What it does / how to use |
|---|---|
| NTP Sync | On = get the time automatically from the internet; off = set it manually via Date Time. |
| NTP Server | Time-server hostname (e.g. at.pool.ntp.org). |
| GMT offset | Seconds offset from UTC. Only used when the Timezone String is empty. |
| Daylight saving time | Extra seconds during summer time. Only used when the Timezone String is empty. |
| Posix Timezone String | POSIX TZ rule for automatic zone + daylight saving; overrides the two offsets above (see examples). |
| Date Time | Manual clock set as YYYY-MM-DD HH:MM:SS (used when NTP Sync is off). |
| Button | What it does / how to use |
|---|---|
| Save | Writes all current settings to the device's flash memory. Text fields are only kept after Save (toggles and live fields apply on the spot). |
| Done/Reboot | Restarts the device so settings that need a reboot take effect, and closes the settings page. Use it after Save. |
| Browse File | Pick a firmware or filesystem .bin file from your phone/computer for the update below. |
| Update Firmware | Flashes the selected .bin as new firmware over WiFi (OTA) — no cable needed. The device reboots when done. |
| Update LittleFS | Flashes the selected .bin as the filesystem image (fonts/graphics), also over WiFi. Only needed when those assets change. |
The code is MIT-licensed and free to use. It does, however, rely on third-party APIs (Binance, Open-Meteo) whose free access is intended for private, non-commercial use. If you intend to use this project commercially, you are responsible for obtaining the appropriate commercial API access/agreements from those providers.