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ESP32 Voice Chatbot

Think of this as your own mini Alexa/Google Assistant, but built by you. You press a button, speak something, and the AI replies back through the speaker.

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How it Works? (The Simple Version)

Even though it’s small, your ESP32 is performing a complex workflow:
  1. ESP32 records your voice when you press the button.
  2. That audio is sent to Deepgram → converts speech to text.
  3. The text is sent to n8n → acts like a middleman.
  4. n8n sends it to Groq AI → generates a reply.
  5. The reply is sent back to Deepgram → converted into audio.
  6. ESP32 receives the audio and plays it through the speaker.

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What You Need

Before starting, make sure you have everything ready.

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Hardware Required

  • ESP32-C3 board (your main device).
  • I2S microphone (to capture your voice).
  • Small speaker (to hear responses).
  • USB cable (for power + uploading code).
Circuit Diagram
Basically: input (mic) → processing (ESP32) → output (speaker)

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Software

  • VS Code with PlatformIO extension.
  • Node.js (v18 or v20).
  • n8n: Workflow automation.
  • Deepgram Accounts: For voice (speech ↔ text).
  • Groq Accounts: For AI responses.
Keep your API keys safe! Without them, your device won’t “understand” or “talk”.

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Software Setup

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Step 1: Install Everything

Take this step slow — this is your foundation.
  1. Install VS Code: This is where everything will happen.
  2. Install PlatformIO: Open VS Code → go to Extensions → Search PlatformIO and install it.
  3. Install Node.js (v18 or v20): Required to run n8n.
  4. Install n8n: Open your terminal and run: 
    npm install -g n8n

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Step 2: Get API Keys

Now you’re connecting your project to real services.
  1. Go to Deepgram → create account → copy API key.
  2. Go to Groq → create account → copy API key.
Think of API keys like passwords that allow your device to use these services.

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Step 3: Setup n8n (The Brain)

n8n is what connects everything together.
  1. Start n8n: Run this in your terminal: 
    n8n start
    Open in browser: http://localhost:5678
  2. Import Workflow:
    • Go to Workflows → Click Import.
    • Copy the JSON code below and paste it into the import box.
    • Click Save and turn it Active (ON).
Workflow
  1. Add Your API Keys:
    • Open Groq node → Replace the existing key with yours.
    • Open Deepgram node → Replace with your key.
  2. Test It (curl command): Run this command in your terminal: 
    curl -X POST http://YOUR_IP:5678/webhook/esp32-voice -d '{"query":"Hello"}'
    • If you get audio → everything is working!

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Step 4: Setup ESP32 Code

Now we move to the device itself.
  1. Create Project Structure: Your folder should look like this: 
    voice-chatbot/
├── lib/
│   └── PCBCUPID_NAU8325/   <-- Add the library here
├── src/
│   └── main.cpp            <-- Your Arduino code
└── platformio.ini          <-- Settings file
  2. Configure platformio.ini: 
    [env:esp32-c3-devkitm-1]
platform = espressif32
board = esp32-c3-devkitm-1
framework = arduino
monitor_speed = 115200
  3. Add Required Library: Download the NAU8325 library and place it inside lib/. Without this, your speaker won’t work.
  4. Full Arduino Source Code: Copy the code below into your main.cpp file.
  1. Update Your Settings: Inside main.cpp, update: 
    const char* WIFI_SSID = "YOUR_WIFI";
const char* WIFI_PASSWORD = "YOUR_PASSWORD";
const char* N8N_HOST = "YOUR_SERVER_IP";
const int N8N_PORT = 5678;
const char* DEEPGRAM_API_KEY = "YOUR_KEY";

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Step 5: Upload Code to ESP32

Now bring your device to life.
  1. Connect ESP32 using USB.
  2. Open project in VS Code.
  3. Click Upload (or run pio run --target upload).

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Step 6: First Boot & Monitor

Open the Serial Monitor (115200 baud). You should see: [READY] Hold BOOT to speak 👉 This means WiFi is connected and the AI is ready to listen!

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Step 7: How to Use

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Voice Mode (Main Feature)

  1. Hold the BOOT button.
  2. Speak clearly into the microphone.
  3. Release the button.
  4. Wait a second for the AI response.
Keep your voice commands short (1–2 seconds) for the fastest response!

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Text Mode (Testing)

Type your message in the Serial Monitor and press Enter. Result Result

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❗ Common Issues (Quick Fixes)

IssueCheck
No SoundCheck speaker wiring & amplifier logs.
No ResponseEnsure n8n is running & WiFi is connected.
Not UnderstandingSpeak louder, hold button longer, check Deepgram API key.
Server Not OpeningCheck http://YOUR_IP:5678 - fix server first.

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Customization (Make It Yours)

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Change AI Personality

Inside n8n, update the prompt: "You are a smart assistant. Reply in one short sentence."

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Adjust Volume

Inside your code, locate and change: 
#define VOL_BOOST 6
Have fun with your mini AI Assistant!