ESP32 Voice to Text Logger Kit with ESP32 + LED
ESP32 Voice-to-Text Logger Kit – Real-Time Speech-to-Text with SD & MQTT
Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.
You’ll build a standalone device that listens to speech through an INMP441 I2S microphone, transcribes it in real time via the Vosk speech recognition engine over WiFi, saves the text with timestamps to a microSD card, and publishes the transcription to an MQTT topic. Use it as a voice logbook for meetings, a voice-controlled note-taker for fieldwork, or the core of an accessibility tool that converts spoken words into storable, shareable text records.
What You'll Build
A compact voice logger that captures high-quality audio, converts it to text locally, and stores time-stamped entries on an SD card while simultaneously broadcasting the text over MQTT. You’ll finish with a working device you can deploy as an IoT speech node, a smart annotation system for lab environments, or an interface for voice-activated dashboards.
What You'll Learn
- Integrate the INMP441 I2S MEMS microphone with ESP32 for lossless digital audio capture
- Configure WiFi and perform HTTP calls to a Vosk server to convert speech to text in near real time
- Timestamp transcriptions using a DS3231 RTC and store them on a microSD card in a structured file format
- Publish recognised text to an MQTT topic so any connected device or dashboard can consume the voice logs
Kit Contents
| Component | Quantity |
|---|---|
| ESP32 Dev Board | x1 |
| INMP441 I2S Mic | x1 |
| DS3231 RTC | x1 |
| MicroSD Module | x1 |
| 0.96in OLED | x1 |
| LM2596 Buck Converter | x1 |
| 4.7kΩ Resistors | x5 |
| 100nF Caps | x10 |
| PCB Prototype Board | x2 |
| Enclosure Box | x1 |
| 5V 2A PSU | x1 |
| Soldering Iron | x1 |
| Solder Wire | x1 |
Why Buy This Kit Instead of Sourcing Parts Separately
| Factor | Sourcing Separately | Compoden Kit |
|---|---|---|
| Compatibility checks | You verify every part | Pre-tested as a system |
| Build support | Forums and scattered tutorials | AI companion trained on this exact project |
| Time to first working build | Days of debugging | Hours, with step-by-step guidance |
| Shipping coordination | Multiple sellers, multiple delays | One shipment from Bengaluru in 3-5 days |
Who This Kit Is For
This advanced kit is built for engineering students (B.Tech ECE, CSE, EEE) tackling final‑year or Smart India Hackathon projects that involve voice interfaces, IoT data pipelines, or accessibility tech. It’s equally suited for researchers and ATL lab mentors at IITs, NITs, VIT, and BITS who need a ready‑to‑assemble reference design for real‑time speech transcription with MQTT integration. If you’ve already built basic ESP32 projects and want to master I2S audio, REST APIs, and network‑connected logging, this kit is your direct path.
Built and Backed by Compoden
Every Compoden kit ships with an AI build companion trained on this exact project — accessible via a QR code on the box, with WhatsApp and email backup. We've spent 10 years building projects for makers, schools, and institutions across India. If a part fails because of a manufacturing defect, replace it free within 7 days.
What if I get stuck during the build?
Tap the QR code to open your AI build companion, which has seen every step of this exact kit. If you still need help, message us on WhatsApp and an engineer will respond within a working day.
Do I need a separate Vosk server to handle speech-to-text?
Yes. The kit uses your own local or cloud Vosk server. We include an easy guide to set it up on a Raspberry Pi or any Linux machine. The AI companion will walk you through configuring the endpoint on the ESP32.
What happens if the WiFi drops during voice capture?
The firmware buffers the audio and automatically retries the connection. If the outage persists, it logs the failure on the OLED and optionally saves the raw audio snippet to the SD card for manual transcription later.
Can I publish the text to a cloud MQTT broker instead of a local one?
Absolutely. The MQTT client configuration accepts any broker address, port, and credentials, so you can push transcriptions directly to AWS IoT Core, HiveMQ Cloud, or any internet‑facing Mosquitto instance.
INMP441 mic streams to Vosk API over WiFi. Transcribed text saved to SD and pushed to MQTT topic.
What's in this kit
Choose your assembly option:
- Soldering Kit — 25W soldering iron, 60/40 solder wire, flux, and small perfboard for permanent assembly.
- Breadboard Combo — 800-point full-size breadboard with 65-piece jumper wire pack for solderless prototyping.
Shipping Information
- Prepaid Orders: ₹75 for orders up to ₹999, FREE shipping above ₹999
- COD Orders: ₹125 shipping + ₹50 COD fee = ₹175 total
- Delivery Timeline: Dispatch in 1-2 days, delivery in 2-7 days depending on location
Returns & Warranty
- 7-Day Return: Manufacturing defects only (approval required)
- Warranty: 7 days from delivery
- Non-Returnable: Batteries, consumables, cut wires, clearance items