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15. STT (Speech-to-Text)

This example demonstrates how to use the STT (Speech-to-Text) module on PiCrawler. The robot listens to your voice through the onboard microphone and converts it into text in real time.

Run the Code

cd ~/picrawler/examples
sudo python3 15_stt.py

After running the program, you will see the language setting and a prompt. The robot starts listening — speak into the microphone and the recognized text will be printed to the terminal.

If no speech is detected, (no speech detected) is shown. Press Ctrl+C to exit.

Before You Start

Make sure you’ve completed:

Install All the Modules (Important) — Install robot-hat, vilib, picrawler modules, then run the script i2samp.sh.

Code

Note

You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path like picrawler\examples. After modifying the code, you can run it directly to see the effect.

#!/usr/bin/env python3
from robot_hat.stt import STT

# Speech recognition demo using sunfounder_voice_assistant STT module
# Press Ctrl+C to exit

# Configure language: "en-us", "zh-cn", etc.
LANGUAGE = "en-us"

def main():
    print("=== PiCrawler Speech-to-Text Demo ===")
    print(f"Language: {LANGUAGE}")
    print("Press Ctrl+C to exit")
    print()

    stt = STT(language=LANGUAGE)

    try:
        while True:
            print("Listening... (speak now)")
            text = stt.listen()
            if text:
                print(f">>> {text}")
            else:
                print("(no speech detected)")
    except KeyboardInterrupt:
        print("\nExiting...")

if __name__ == "__main__":
    main()

How it works?

Importing the STT Module
```
from robot_hat.stt import STT
```
The STT class is part of the robot_hat package. It handles all the low-level audio capture and speech recognition processing.
Setting the Language
```
LANGUAGE = "en-us"
```
The LANGUAGE variable configures the recognition language. You can change it to other supported codes such as "zh-cn" (Chinese) depending on your needs.
Creating the STT Instance
```
stt = STT(language=LANGUAGE)
```
This creates an STT object configured for the chosen language. The object initializes the microphone and the speech recognition engine.
The Listening Loop
```
while True:
    print("Listening... (speak now)")
    text = stt.listen()
    if text:
        print(f">>> {text}")
    else:
        print("(no speech detected)")
```
The program runs an infinite loop where each iteration:
- Prompts the user to speak.
- Calls stt.listen() which blocks until speech is detected and processed.
- Returns the recognized text as a string, or None / empty if nothing was understood.
- Prints the result to the terminal.
Graceful Exit
```
except KeyboardInterrupt:
    print("\nExiting...")
```
Pressing Ctrl+C raises a KeyboardInterrupt, which is caught to print an exit message and terminate the program cleanly.