Speech Synthesis On A 10 Cent Microcontroller

October 31, 2025 by Lewin Day 53 Comments

Speech synthesis has been around since roughly the middle of the 20th century. Once upon a time, it took remarkably advanced hardware just to even choke out a few words. But as [atomic14] shows with this project, these days it only takes some open source software and 10-cent microcontroller

The speech synth is implemented on a CH32V003 microcontroller, known for its remarkably low unit cost when ordered in quantity. It’s a speedy little RISC-V chip running at 48 MHz, albeit with the limitation of just 16 KB of Flash and 2 KB of SRAM on board.

The microcontroller is hooked up to a speaker via a simple single-transistor circuit, which allows for audio output. [atomic14] first demonstrates this by having the chip play back six seconds of low quality audio with some nifty space-saving techniques to squeeze it into the limited flash available. Then, [atomic14] shows how he implemented the Talkie library on the chip, which is a softwarehttps://www.youtube.com/watch?v=RZvX95aXSdM implementation of Texas Instruments’ LPC speech synthesis architecture—which you probably know from the famous Speak & Spell toys. It’s got a ton of built in vocabulary out of the box, and you can even encode your own words with some freely available tools.

We’ve seen [atomic14] tinker with these chips before, too.

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Say Watt? A Talking Multimeter?

March 23, 2014 by Marsh 41 Comments

talkingMultimeter

After a request from one of his friends, [Mastro Gippo] managed to put together a talking multimeter to be used by blind persons working in electronics. He wanted a feature-rich meter that had serial output, and recalling this Hackaday article from a few years back led him to find a DT-4000ZC on eBay, which has serial output on a 3.5mm jack. (Though, he actually recommends this knockoff version which comes with excellent documentation).

It turns out there aren’t many talking meter options available other than this expensive one and a couple of discontinued alternatives. [Mastro Gippo] needed to start from scratch with the voice synthesizer, which proved to be as easy as recording a bunch of numbers and packing them onto an SD card to be read by an Arduino running the SimpleSDAudio library.

He found a small, battery-powered external speaker used for rocking out with music on cell phones and hooked it up to the build, stuffing all the electronics into an aluminum case. Stick around after the jump for a quick video of the finished product!

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A Talking Reverse Geocache Puzzle Box

January 20, 2012 by Mike Szczys 2 Comments

Here’s a talking reverse geocache puzzle box which [Erv Plecter] built as a wedding gift for his friends. The box itself isn’t really the gift, but a surprise delivery system for a collection of cash from the couple’s circle of friends to go toward the honeymoon. We think this is about fifty times more fun that getting a fat envelope of bills. Who would really expect to find cash inside once you finally get to the target location?

Unlike the other geocache box we saw recently, this one has no display to show you clues to the destination. Instead, it plays back audio clips which [Erv] recorded himself. They’re quite tongue-in-cheek which is another nice personal touch. The pin seen protruding out of the right side of the box can be removed to play a clue and check the location. It’s connected by a little chain to a 5 euro-cent piece which conceals an emergency release mechanism for the lid. The device is powered with a Lithium battery and can be recharged without opening the box via a USB port in the side.

We’ve embedded the video demonstration of the box after the break.

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Talking Clock Sounds Just Like You

May 23, 2010 by Mike Szczys 18 Comments

[vimeo=http://www.vimeo.com/10852914]

We’d bet a large portion of our readers don’t remember when you could call the phone company and get the time of day. Gadget Gangster is bringing back the tried and true method with this talking clock. Just press the button and the ‘operator’ will read the time of day to you. Record your own voice and place the WAV files on an SD card, from there a Propeller chip takes care of the rest.

As a side note, we’re big fans of the method used to breadboard the power supply using the TO-220 package leads as their own jumpers. We’ve always been partial to using a breadboard regulator on a PCB but this method is simple and takes almost no space at all.