Universal remote

Universal Remote

ESP32-based universal infrared remote control with touch screen. It can learn IR signals, save them to an SD card, resend them, and transmit built-in brand codes. The entire UI is touch-controlled, featuring scrollable lists and a virtual keyboard.

Hardware

The display and the SD card use the same SPI bus (shared MOSI/MISO/CLK), multiplexed with CS lines. Before sending an IR signal, the code sets SD_CS and TOUCH_CS HIGH to avoid bus conflicts.

Pinout

Dependencies

• LovyanGFX - display + touch driver (ILI9341 + XPT2046)
• IRremoteESP8266 - IR receive / send / decode
• Preferences - ESP32 NVS (for saving themes)
• SD, SPI - Arduino ESP32 core built-in
• ./IR-codes.h - custom header with built-in Pronto Hex codes (EPSON and NEC arrays). Without this, the project will not compile.

Features

Signal learning (Receive)

1. Signal options -> Receive starts listening mode.
2. The receiver decodes the signal into decode_results.
3. The code accepts a maximum of 3 frames at once within a signal (MAX_FRAMES = 3), measuring the pause between them as gap_ms.
4. Repeat frames and identical frames are discarded.
5. An UNKNOWN (raw) signal is only accepted if it is the first frame, and contains at least 10 pulses, filtering out noise.
6. The captured signal type is determined automatically:
   • SIG_VALUE - known protocol, fixed-length value (e.g., NEC)
   • SIG_STATE - AC-like protocols with byte-array states
   • SIG_RAW - unknown, raw microsecond array
7. After capture, a QWERTY keyboard appears to name the signal (max 25 characters, letters + -).
8. Saved to the SD card: /saved-signals/<group>/<name>.txt.

Signal sending (Transmit)

• Saved signals: Signal options -> Transmit -> group list -> signal list -> Send. The group is the part of the signal's name before the - (e.g., TV-power -> TV group).
• Built-in signals: Built-in signals -> brand -> signal -> Send.
• Long pressing the Send button repeats the signal (except for SIG_STATE signals).
• Transmission strategy:
  • SIG_VALUE: irsend.send(protocol, value, bits) - for RC5/RC6, the toggle bit switches automatically on each new press.
  • SIG_STATE: irsend.send(protocol, state, bytes).
  • SIG_RAW: irsend.sendRaw(rawData, len, khz).
  • If protocol sending returns false, but raw data is available, an automatic raw fallback occurs.
• For multi-frame signals, there is a gap_ms pause between frames.

Built-in signals

The IRCode structures declared in IR-codes.h store the codes in Pronto Hex format. The firmware converts them to raw microsecond arrays using the prontoToRawSignal() function and calculates the carrier frequency with prontoCarrierKHz().

Currently, only these are available from the UI in the hardcodedBrands[] array:

• EPSON
• NEC

(Other brands will only appear if you add them to the array.)

SD Card Management

• Info - total / free / used space + number of saved signal files.
• Files - file browser with directory navigation, size display, and individual file deletion (Del button, !NO CONFIRMATION MESSAGE!).
• Format - keeps the /System Volume Information and /built-in-signals directories, deletes everything else.
• File list limit: 500 items.

UI / Themes

Three selectable color themes (persisted in NVS):

• Futuristic Red (default)
• Futuristic Green
• Futuristic Purple

Theme switching is displayed with an animated spreading circle effect.

Other UI features:

• Boot splash: UNIVERSAL / REMOTE text for ~2 seconds.
• Scrollable lists with a sprite buffer (LGFX_Sprite) to prevent flickering.
• Double tap on a list item = open.
• Long hold on a repeatable button = rapid fire (REPEAT_INTERVAL = 200 ms).
• Maximum number of buttons per screen: 30.
• Button style: corner accents + scanline pattern.

Navigation Structure

Main Menu
├── Signal options
│   ├── Transmit  ->  [Group]  ->  [Signal list]  ->  Send
│   └── Receive   ->  Listening... ->  Captured!   ->  Keyboard -> Save
├── Built-in signals
│   └── [Brand]   ->  [Signal list] ->  Send
├── SD Card options
│   ├── Info
│   ├── Files  ->  browser (Up / Back / Del)
│   └── Format ->  Yes, format / Cancel formatting
└── Change theme
    ├── Futuristic Red
    ├── Futuristic Green
    └── Futuristic Purple

If SD initialization fails, "SD Card options" disappears from the main menu.

Saved signal file format

Not binary - each signal is a simple, line-separated .txt file:

# UniRemote IR signal
name: TV-power
carrier_khz: 38
frame: 1
gap_ms: 40
protocol: NEC
bits: 32
value: 0x20DF10EF
length: 68
raw: 9000,4500,560,560,...
frame: 2
...

Fields per frame:

• gap_ms - pause before the next frame (only if there is a next frame)
• protocol - name returned by typeToString()
• bits - number of bits for SIG_VALUE, bytes×8 for SIG_STATE
• value - hex value (SIG_VALUE)
• bytes - space-separated hex bytes (SIG_STATE)
• length + raw - raw microsecond array (always saved if available)

When loading the file, the code automatically determines the kind based on the existing fields: value -> state -> raw priority.

Folder structure:

/saved-signals/
├── TV/
│   ├── power.txt
│   └── mute.txt
├── Misc/
│   └── random-signal.txt

Names without - are automatically placed in the Misc group.

File structure