1. TTS with Espeak and Pico2Wave

In this lesson, we’ll use two built-in text-to-speech (TTS) engines on Raspberry Pi — Espeak and Pico2Wave — to make the Pironman 5 Pro MAX talk.

These two engines are both simple and run offline, but they sound quite different:

Espeak: very lightweight and fast, but the voice is robotic. You can adjust speed, pitch, and volume.
Pico2Wave: produces a smoother and more natural voice than Espeak, but has fewer options to configure.

You’ll hear the difference in voice quality and features.

1. Testing Espeak

Espeak is a lightweight TTS engine included in Raspberry Pi OS. Its voice sounds robotic, but it is highly configurable: you can adjust volume, pitch, speed, and more.

Run the program

cd ~/sunfounder-voice-assistant/examples
sudo python3 tts_espeak.py
You should hear the Pironman 5 Pro MAX say: “Hello! I’m Espeak TTS.”

Try changing the tuning parameters in the code to experiment with how amp, speed, gap, and pitch affect the sound.

Code

from sunfounder_voice_assistant.tts import Espeak

# Create Espeak TTS instance
tts = Espeak()
# Set amplitude 0-200, default 100
tts.set_amp(200)
# Set speed 80-260, default 150
tts.set_speed(150)
# Set gap 0-200, default 1
tts.set_gap(1)
# Set pitch 0-99, default 80
tts.set_pitch(80)

tts.say("Hello! I’m Espeak TTS.")

Code explanation:

tts.set_amp() — Controls the volume (0–200).
tts.set_speed() — Adjusts the speaking speed (80–260).
tts.set_gap() — Sets the word gap (0–200).
tts.set_pitch() — Sets the pitch (0–99).
tts.say() — Converts text to speech and plays it.

💡 Tip: Try increasing the pitch and speed to make the robot sound cheerful, or lowering them to make it sound serious.

2. Testing Pico2Wave

Pico2Wave produces a more natural and human-like voice compared to Espeak. It’s very easy to use, but less flexible — you can only change the language, not the pitch, speed, or volume. This makes Pico2Wave a great choice when you want clear and smooth speech without too much configuration.

Run the program

cd ~/sunfounder-voice-assistant/examples
sudo python3 tts_pico2wave.py

You should hear the Pironman 5 Pro MAX say: “Hello! I’m Pico2Wave TTS.”
Try changing the language (for example, es-ES for Spanish) and listen to how the voice changes.

Code

from sunfounder_voice_assistant.tts import Pico2Wave

# Create Pico2Wave TTS instance
tts = Pico2Wave()

# Set the language
tts.set_lang('en-US')  # en-US, en-GB, de-DE, es-ES, fr-FR, it-IT

# Quick hello (sanity check)
tts.say("Hello! I'm Pico2Wave TTS.")

Code explanation:

tts.set_lang() — Sets the output language for speech synthesis.
- en-US (default)
- en-GB
- de-DE
- es-ES
- fr-FR
- it-IT
tts.say() — Converts the text to speech and plays it immediately.

Troubleshooting

No sound when running Espeak or Pico2Wave
- Check that your speakers/headphones are connected and volume is not muted.
- Run a quick test in terminal:
```
espeak "Hello world"
pico2wave -w test.wav "Hello world" && aplay test.wav
```
If you hear nothing, the issue is with audio output, not your Python code.
Espeak voice sounds too fast or too robotic
- Try adjusting the parameters in your code:
```
tts.set_speed(120)   # slower
tts.set_pitch(60)    # different pitch
```
Permission denied when running code
- Try running with sudo:
```
sudo python3 test_tts_espeak.py
```

Comparison: Espeak vs Pico2Wave

Feature	Espeak	Pico2Wave
Voice quality	Robotic, synthetic	More natural, human-like
Languages	Default English	Fewer, but common ones
Adjustable	Yes (speed, pitch, etc.)	No (only language)
Performance	Very fast, lightweight	Slightly slower, heavier