View this project on CADLAB.io.

TTS

Text-to-Speech Library for Arduino

• checkout this project into your sketchbook/libraries folder
• requires an amplifier on the PWM output pin (see below)
• see blog articles

Supported Hardware

• ATmega328-based Arduinos (e.g., Uno, Pro, Pro Mini, etc.): pins 3, 9, 10
• ArduTouch: pin 9
• ATmega1280-based Arduinos (e.g., Mega): pins 44, 45, 46
• Arduino Leonardo: pin 5
• Arduino Due: pins DAC0 or DAC1
• Teensy 3.2: pin A14
• Teensy 3.5, 3.6: pins A21, A22
• Teensy LC: pin A12
• ESP8266: pins 0 to 16 (with analogWrite())
• ESP32: DAC1 or DAC2 (pins 25 or 26)

Amplifier

Component choices in this circuit aren't very critical:

• 22k (vs 27k) and 47n (vs 10n) parts in the input low-pass filter
• 100n (vs 10u) bypass capacitor between pin 7 and gnd
• Used the inverting input instead of the non-inverting one (although in this circuit I noticed no difference)
• 47n (vs 100n) output snubber capacitor

Credits

• original implementation by Clive Webster in Webbotlib
• ported to Arduino by Gabriel Petrut
• Stephen Crane modified it to use pins other than pin 10 with the help of this tutorial
• manitou48 added support for Leonardo and ARM processors with DAC (Teensy, Due)

See Also

• Teensy forum
• separate port/hack for MBED ARM with DAC repository
• Hackaday article on LM386 amplifiers