WT2605B02 Audio Module
MP3 Recording & Playback Module with TF Card/USB Storage, Built‑in 1W Amplifier & UART Control
The WT2605B02 is a versatile MP3 recording and playback module designed for a wide range of audio applications. It supports TF card and USB drive storage with index and filename based playback and recording. With a built‑in 1W Class‑D amplifier, 32‑level volume control, and UART serial interface (9600 baud), it offers flexible control for intercom systems, conference recording, and industrial audio equipment.
- MP3 recording & playback – high‑quality audio
- TF card & USB – up to 32GB each
- Built‑in 1W amp – direct 8Ω speaker drive
- 32‑level volume – precise audio control
- UART control – simple serial commands
Key Features
Specifications
| Parameter | Value / Condition |
|---|---|
| Operating Voltage | 3.0V – 5.2V |
| Operating Current | 20 – 250 mA (load dependent) |
| Standby Current | ~27.6 mA |
| Recording Current | ~28.1 mA |
| Playback Current (no load) | ~28.7 mA |
| IO Port Level | 3.3V TTL |
| Audio Formats | MP3 (8–48kHz, 8–320kbps), WAV (8–44.1kHz) |
| Storage Media | TF card (32GB), USB drive (32GB), FAT/FAT32 |
| Recording Inputs | MIC, LINE-IN, AUX (stereo) |
| Amplifier Output | 1W @ 8Ω (Class‑D) |
| DAC SNR | 92 dB |
| DAC THD+N | ‑70 dB (no load) |
| DAC Max Output | 2.8 Vpp (10kΩ load) |
| Control Interface | UART (9600 baud, 3.3V TTL) |
| USB Interface | USB 2.0 full-speed |
| Module Size | 21.21 × 18.24 × 3.35mm (±0.3mm) |
| Pin Pitch | 2.0mm |
| Operating Temperature | ‑40°C ~ +85°C |
Recording Features
MIC Recording
- Onboard microphone input
- 10dB gain (default)
- Configurable via D3 command
LINE-IN Recording
- External line input
- 3dB gain
- Mono recording
- Input amplitude ≤ 2.8V
AUX Stereo Recording
- AUX_L + AUX_R inputs
- 3dB gain
- Stereo recording
- Input amplitude ≤ 2.8V
Recording commands: Index recording (D5), filename recording (D6), folder+index (D7), folder+filename (D8). Stop recording with D9. Supports up to 999 index recordings (REXXX.MP3).
UART Command Set
| Command | Function | Description |
|---|---|---|
| A2 | Index Playback | Play audio by index in root directory |
| A3 | Filename Playback | Play audio by filename (≤8 or >8 characters) |
| A4 | Folder Index Playback | Play by index in specified folder |
| A5 | Folder Filename Playback | Play by filename in specified folder |
| AA | Pause / Resume | Toggle pause/playback |
| AB | Stop | Stop current playback |
| AC/AD | Next / Previous | Track navigation |
| AE | Volume Control | Set volume (0–31, default 16) |
| AF | Playback Mode | Normal / Single loop / All loop / Random / Folder loop |
| D0/D1 | Fast Forward / Rewind | Toggle fast forward/rewind |
| D2 | Storage Select | Switch between TF card and USB |
| D3 | Input Channel & Gain | MIC (10dB) / LINE-IN (3dB) / AUX stereo (3dB) |
| D5–D8 | Recording Commands | Index / filename / folder+index / folder+filename recording |
| D9 | Stop Recording | Stop current recording session |
| DA–DE | Delete Commands | Delete by index, filename, folder+index, folder+filename, or delete all |
| C1–C9 | Query Commands | Volume, status, file count, current track, connection status |
| CB/CC | File Search | Check if file exists in root directory or folder |
| CE | Remaining Space | Query storage remaining capacity |
Protocol format: 7E + Length + Command + Parameters + Checksum + EF. Return codes: 0x00 = OK, 0x01 = file not found / storage full, 0x02 = error.
Pin Functions (20‑Pin Module)
| Pin | Name | Function |
|---|---|---|
| 3 | SPK+ | Speaker positive |
| 4 | SPK− | Speaker negative |
| 5 | DACR | DAC right channel output |
| 6 | DACL | DAC left channel output |
| 7 | AUX_L | AUX recording left input |
| 8 | AUX_R | AUX recording right input |
| 9 | MIC / P03 | Microphone input / LINE-IN |
| 12 | TXD | UART transmit |
| 13 | RXD | UART receive |
| 16 | VCC33 | 3.3V LDO output (low-power only) |
| 17 | BUSY | Busy signal output |
| 18 | VDD50 | Power input (3.0–5.2V) |
| 19 | DM | USB D− |
| 20 | DP | USB D+ |
VCC33 is for low‑power devices only – do not use to power external circuits.
Application Scenarios
Why Choose WT2605B02
Frequently Asked Questions
What is the WT2605B02?
WT2605B02 is a high-quality MP3 recording and playback module with TF card and USB storage, index and filename based control, built-in 1W amplifier, and UART serial interface.
What storage media are WT2605B02 supported?
WT2605B02 supports TF card (microSD) up to 32GB and USB drives up to 32GB. The module can switch between internal and external storage via command.
What recording options are available?
WT2605B02 supports MIC recording, LINE-IN recording, and AUX stereo recording. Recording can be triggered by index or filename, with adjustable gain and bitrate.
Does WT2605B02 have a built-in amplifier?
Yes. WT2605B02 features a built-in 1W Class-D amplifier that can directly drive an 8Ω/1W speaker, with 32-level volume control.
What control interface does it use?
It uses a standard UART interface with default baud rate 9600, 3.3V TTL level. Commands follow a 7E … EF protocol.
How many volume levels are available?
32 levels (0 to 31), with 0 = mute and 31 = maximum volume. Default is level 16. Volume can be saved with EEPROM.
What audio formats are supported?
It supports MP3 (8–320kbps, 8–48kHz) and WAV (8–44.1kHz) audio formats.
Can I delete files via commands?
Yes. You can delete files by index, by filename, by folder + index, or by folder + filename. The module also supports full deletion of all audio files.
What is the module size?
The module measures 21.21mm × 18.24mm × 3.35mm (±0.3mm) with 2.0mm pin spacing.
What are the typical applications?
Building intercom systems, conference recording equipment, railway recording devices, voice prompt systems, and any application requiring audio recording and playback with UART control.
Important: The module is 3.3V IO – use level shifting for 5V MCU connections. VCC33 is for low‑power devices only – do not use to power external circuits. Recording data is saved every 5 seconds – power loss during this window may result in data loss. Do not remove power or storage media during deletion operations. The module cannot withstand wave or reflow soldering due to the internal TF card. Wait for return codes after recording commands before sending new commands. Command interval should be ≥100ms.
