Ai-Thinker ESP32-A1S Audio Development Kit V2.2 - Wi-Fi/BT with Dual Mics & MicroSD

Specifications

• Core Module: Ai-Thinker ESP32-A1S (Wi-Fi + BT SoC Inside)

• Memory: 4MB SPI Flash / 4MB PSRAM (Integrated)

• Audio Codec: Integrated inside the A1S module

• Audio Output: 1 x 3.5mm Earphone Jack, 2 x Speaker Out (LOUT/ROUT JST connectors)

• Audio Input: 1 x 3.5mm Line-In Jack, 2 x Onboard Microphones

• Storage: MicroSD Card Slot

• User Interface: 6 x Programmable Keys, 5-Pin DIP Switch Block

• Power Supply: 5V via Micro-USB or 3.7V via LiPo Battery port

Key Applications and Projects

• DIY Smart Speakers: Building custom voice assistants that wake up to a trigger word and query cloud services via Wi-Fi using the dual microphones.

• Internet Radio Receivers: Streaming global web radio stations and decoding the audio streams in real-time for stereo playback.

• Two-Way Intercoms: Creating a Wi-Fi-based walkie-talkie system for your home.

• Audio Storyboxes: Designing interactive, battery-powered toys that play specific MP3s from the SD card when the side buttons are pressed.

Unlock New Capabilities (Project Evolution)

• Software Ecosystem: While basic Arduino sketches work, the true power of this board is unlocked by using the Espressif Audio Development Framework (ESP-ADF). It provides extensive, optimized libraries for audio streaming, decoding (MP3, AAC, FLAC), and advanced voice recognition!

Downloads and Links:

• ESP32-A1S_Datasheet
• ESP32-A1S-AudioKit_Github
• ESP-ADF-Component-Ai-thinker-ESP32-A1S_Github

Package Includes:

• 1 x Ai-Thinker ESP32-A1S Audio Development Kit V2.2

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What makes the ESP32-A1S module different from a standard ESP-WROOM-32? The ESP32-A1S ingeniously integrates the Wi-Fi/BT chip, PSRAM, and a dedicated audio codec IC all inside the single metal shielded can. Standard modules require an external codec chip on the main board.

2. Does this board support true stereo audio? Yes! It features Left and Right speaker outputs (LOUT and ROUT) as well as a stereo 3.5mm earphone jack.

3. Are there microphones built into the board? Yes, there are two electret microphones (MIC1 and MIC4) soldered directly to the board for stereo voice capture or noise cancellation.

4. Can I connect external speakers directly? Yes, the LOUT and ROUT white JST connectors have a small onboard amplifier circuit capable of driving small 4-ohm or 8-ohm micro speakers directly.

5. What is the difference between the two 3.5mm jacks? The one labeled "EARPHONES" is your audio output. The one labeled "LINEIN" is an analog audio input for recording music from an external source.

6. Why are there two Micro-USB ports? The port labeled "UART / POWER" connects to the onboard serial chip for programming the board via your PC. The other port is used solely for supplying 5V power if you don't need data.

7. Can I run this on battery power? Yes, there is a white 2-pin JST connector labeled "BAT+" on the top edge for connecting a standard 3.7V Lithium-Polymer (LiPo) battery.

8. Will it charge my attached LiPo battery? Yes, when a battery is attached and USB power is supplied, the board's internal circuitry will safely charge the battery.

9. What is the MicroSD slot used for? It allows you to store massive libraries of local MP3/WAV files for playback, or to log audio data recorded by the microphones.

10. What do the KEY1 through KEY6 buttons do? These are programmable GPIO tactile buttons. They are perfectly positioned to be programmed as media controls (Play, Pause, Next, Volume Up/Down).

11. What is the block of 5 switches in the middle? That is a DIP switch block. Depending on the firmware and specific board revision, these switches are used to route specific audio lines or enable/disable power to the amplifier circuit.

12. Can I use the Arduino IDE to program this? Yes, you can use the standard ESP32 core in Arduino, but for advanced audio streaming and voice recognition, the ESP-ADF framework is highly recommended.

13. Why does it say V2.2 2957 on the board? This indicates the specific hardware revision. Ai-Thinker has released a few versions of this board; V2.2 is one of the most stable and widely supported.

14. What are the pins on the bottom right (GND, IO0, RST, TX0, RX0)? That is the primary UART programming header. While you usually use the USB port, you can use an external FTDI programmer on these pins if the USB chip fails.

15. Does the board have built-in PSRAM? Yes, the A1S module contains 4MB of PSRAM, which is absolutely crucial for buffering audio streams without stuttering.

16. Can it do voice wake-up (like "Alexa")? Yes, using the ESP-ADF software, you can run wake-word engine (WWE) algorithms to trigger actions based on spoken phrases.

17. Does it support Bluetooth Audio? Yes, the ESP32 supports A2DP, allowing you to program the board to act as a Bluetooth speaker receiver or a Bluetooth audio transmitter.

18. What are the JTAG pins for? The header labeled "JTAG" allows advanced users to connect a hardware debugger (like an ESP-Prog) to step through their code line-by-line.

19. What is the back of the board like? The back is mostly flat with circuit traces and solder points. It clearly marks the ESP32-A1S module footprint but has no major interactive components.

20. Is the board ready to play music out of the box? No, it is a development board. It requires you to write and upload firmware (code) before it will play or record any audio.