speech synthesis

30 Articles

A small speaker with an LCD showing chatbot responses

AI-Powered Speaker Is A Chatbot You Can Actually Chat With

April 22, 2023 by 20 Comments

AI-powered chatbots are pretty cool, but most still require you to type your question on a keyboard and read an answer from a screen. It doesn’t have to be like that, of course: with a few standard tools, you can turn a chatbot into a machine that literally chats, as [Hoani Bryson] did. He decided to make a standalone voice-operated ChatGPT client that you can actually sit next to and have a conversation with.

The base of the project is a USB speaker, to which [Hoani] added a Raspberry Pi, a Teensy, a two-line LCD and a big red button. When you press the button, the Pi listens to your speech and converts it to text using the OpenAI voice transcription feature. It then sends the resulting text to ChatGPT through its API and waits for its response, which it turns into sound again through the eSpeak speech synthesizer. The LCD, driven by the Teensy, shows the current status of the machine and also provides live subtitles while the machine is talking.

To spice up the AI box’s appearance, [Hoani] also added an LED ring which shows a spectrogram of the audio being generated. This small addition really makes the thing come alive, turning it into what looks like a classic Sci-Fi movie prop. Except that this one’s real, of course – we are actually living in the future, with human-like AI all around us.

All code, mostly written in Go, is freely available on [Hoani]’s GitHub page. It also includes a separate audio processing library called toot that [Hoani] wrote to help him interface with the micophone and do spectral analysis. Anyone with basic electronic skills can now build their own AI companion and talk to it – something that ham radio operators have been doing for a while.

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2022 Hackaday Prize: Talking Clock Built With Old-School Gear

August 16, 2022 by 2 Comments

Any smartphone or laptop could be a talking clock if you wished it so. However, we think this build from [Marek Więcek] is more fun, which uses discrete vintage chips to get the job done the old fashioned way.

The work started when [Marek] was tinkering with a 65C02 CPU, giving it an EPROM, some RAM, and some logic ICs to create something akin to a modern microcontroller in functionality. It came to be known as the 6502 Retro Controller Board. Slowly, the project was expanded with various additional modules, in much the same way one might add shields to an Arduino.

In this case, [Marek] expanded the 6502-powered board with a series of 7-segment displays, along with an RTC to keep accurate time. A classic SP0256-AL2 speech synthesis chip was then added, allowing the system to not only show the time, but read it aloud, too. As a bonus, not only can it tell you the hour, minute, day, and date, but it will also read various science-fiction quotes on demand.

Like most 80s speech synths, the output is robotic and a little difficult to parse. However, that’s part of the charm that makes it different compared to the speaking virtual assistants of today.

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Breadboard containing speech synthesis chip

RPi Python Library Has Retro Chiptunes And Speech Covered

September 9, 2021 by 4 Comments

The classic SP0256-AL2 speech chip has featured a few times on these pages, and if you’ve not seen the actual part before, you almost certainly have heard the resulting audio output. The latest Python library from prolific retrocomputing enthusiast [Nick Bild] brings the joy of the old chip to the Raspberry Pi platform, with an added extra trick; support for the venerable AY-3-8910 sound generator as well.

The SP0256-AL2 chip generates vaguely recognisable speech using the allophone system. Allophones are kind of like small chunks of speech audio which when reproduced sequentially, result in intelligible phonemes that form the basis of speech. The chip requires an external device to feed it the allophones at a regular rate, which is the job of his Gi-Pi library.

This speech synthesis technology is based on Linear-predictive coding, which is used to implement a human vocal tract model. This is the same coding method utilized by the first generation of GSM digital mobile phones, implementing a system known as Full-Rate. Both an LPC encoder and an LPC decoder are present on the handset. The LPC encoder takes audio in from the user, breaks it into the tiny constituent parts of speech, and then simply sends a code representing the audio block, but not the actual audio. Obviously there are a few more parameters sent as well to adjust the model at the receiving side. The actual decoding side is therefore not all that dissimilar to what the AY-3-8910 and related devices are doing, except you the user have to create the list of audio blocks up-front and feed the chip at the rate it demands.

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Give Me A Minute, My Eyes Are Busy

September 11, 2020 by 3 Comments

Social cues are tricky, but humans are very good at detecting where someone is looking; that goes a long way toward figuring out where someone is placing their attention. All of this goes right out the window though, when you’re talking with somebody who uses eye-tracking software to speak. [Matthew Oppenheim] with Lancaster University, UK wants to give listeners the message of Give Me a Minute with an easy-to-recognize indicator. His choice is a microBit, which displays a rotating arrow on the LED array while someone composes their speech. He chose the microBit because they are readily available, and you can get cases to fit people’s personalities. After the break, you can see a demonstration, but the graphic appears scrambled because of the screen flicker. The rotating arrow is a clear indicator that someone is writing, whereas a clock might suggest a frozen computer, and a progress bar could not be accurate.

[Matthew] wrote a program for the interpreting computer which recognizes when a message is forming by monitoring the number of black pixels in the composition field. If it changes, someone must be composing a sentence. Many people will try to peek over the speaker’s shoulder and see if they are working, but we’re sure that most readers would join the users of such tech in being unhappy if someone blatantly looks at theirr computer screen while they are typing.

Wheelchairs don’t always have to come from a hospital or supply store, and they don’t have to stay on the ground.

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38 Years Later, The Atari 2600 Learns To Speak

August 27, 2020 by 11 Comments

Back in the early 1980s, there was a certain fad in making your computer produce something resembling human speech. There were several hardware solutions to this, adding voices to everything from automated telephone systems to video game consoles, all the way to Steve Jobs using the gimmick to introduce Macintosh to the world in 1984. In 1982, a software-based version of this synthesis was released for the Atari 8-bit line of computers, and ever since them [rossumur] has wondered whether or not it could run on the very constrained 2600.

Fast-forward 38 years and he found out that the answer was that yes, it was indeed possible to port a semblance of the original 1982 Software Automatic Mouth (or SAM) to run entirely on the Atari 2600, without any additional hardware. To be able to fit such a seemingly complicated piece of software into the paltry 128 bytes (yes, bytes) of RAM, [rossumur] actually uses an authoring tool in order to pre-calculate the allophones, and store only those in the ROM. This way, the 2600 alone can’t convert text to phonemes, but there’s enough space left for the allophones, which are converted into sound, that about two minutes of speech can fit into one cartridge. As for why he went through the trouble, we quote the author himself: “Because creating digital swears with 1982 speech synthesis technology on a 1977 game console is exactly what we need right now.”

For this project, [rossumur] has written an incredibly interesting article on speech synthesis in order to explain the SAM engine used here. And this isn’t his first time on the website either, always cramming software where it shouldn’t fit, such as a “Netflix”-like streaming service, or 8-bit console emulators, both on nothing but an ESP32 microcontroller. Check this one out in action after the break.

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Giving The Amstrad CPC A Voice And A Drum Kit

August 12, 2019 by 7 Comments

Back in the ’80s, home computers weren’t capable of much in terms of audio or multimedia as a whole. Arguably, it wasn’t until the advent of 16-bit computers such as the Amiga that musicians could make soundtrack-quality music without having to plug actual studio gear up to their machines. [Michael Wessel] is trying to bring some of that and many more features to the Amstrad CPC with his ambitious LambdaSpeak 3 project, an expansion card built completely up from scratch and jam-packed with features.

First, and likely giving it its name, is the speech synthesizer. [Michael] has made an emulation mode where his card can act just like the original SSA-1 expansion, being able to be controlled by the same software as back then. By default, the card offers this mode with an Epson S1V30120 daughterboard (which is based on DECTalk synthesis), however for further authenticity you also have the option of fitting it with an SP0256-AL2 chip, the same one used in the original Amstrad hardware in 1985.

As for the more musical part of the project, the board supports 4-channel PCM playback, much like the Amiga’s sound offering. This can be used for a drum machine sequencer program, and it has an Amdrum mode, emulating another expansion from the original Amstrad days. Sample playback can also be used alongside the speech synthesis as shown here, with random allophone beats that wouldn’t sound out of place in a Kraftwerk recording. Finally, by using the UART interface included on the LambdaSpeak, you can also turn the CPC itself into a synth by giving it MIDI in/out and interfacing a controller in real time with the computer’s AY-3-8912 sound chip.

If you like modern expansions giving old computers new life, did you know that you can get just about any retro computer online, perhaps a TRS-80, an Amiga and even a Psion Organizer? And if you’re interested in just using old systems’ sound chips with modern USB MIDI controllers, it’s easy to make a microcontroller do all the heavy lifting.

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Vintage Speech Synthesizer Croons The Oldies

June 11, 2019 by 33 Comments

If you listened to the National Weather Service Weather Radio in the US about 25 years ago, you’ll no doubt remember [Perfect Paul], one of the synthesized voices used to read current conditions and weather forecasts. The voice came from a DECtalk DTC01, a not inexpensive voice synthesizer first made in 1984 that also gave voice to [Stephen Hawking] for many years.

Long obsolete, the DECtalk boxes have a devoted following with hobbyists who like to stretch what the device can do. Some even like to make it sing, after a fashion, and [Michael] decided that making a DECtalk sing “Xanadu”, the theme song from the 1980 [Olivia Newton-John] musical extravaganza, was a good idea. Whether it actually was is debatable, and we’ll take exception with having that particular ditty stuck in our head as a result, but we don’t judge except on the merits of the hack.

It’s actually easy if you have a DECtalk; the song is a straight ASCII file with remarkably concise instructions on which phonemes the box needs to generate. Along with inflection, tone, and timing instructions, the text file looks almost completely unlike English while still somehow being readable. The DECtalk accepts the file over RS-232, which would be easy enough to do with a modern computer, but [Michael] upped his game a bit by using a TRS-80 Model 100 computer as a serial terminal. The synthesized song is in the video below, with the original included for reference by those who didn’t experience endure the late disco-era glory days.

DECtalks seem pretty rare in the wild, so we appreciate this glimpse at what they can do. There are other retro speech synthesizer hacks, though: the simulated walnut goodness of the Votrax and the MicroVox come to mind, as does the venerable TI Speak and Spell.

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