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RoboVoice Shield / Break-Out

"A low-cost Text-to-Speech solution for your Robotics Projects!"

RoboVoice Shield demo

The newest member of our family of Text-to-Speech Shield kits - the RoboVoice Shield is available as either a complete ready-to-build and plug-in-and-go kit to add to your project (RoboVoice Shield / Breakout Deluxe - which also includes a 2" speaker!) or as a PC board only - where you find the parts and build it yourself (RoboVoice Shield / Breakout PCB) Both are available NOW from the DroidBuilder store!

A Quick Overview of our RoboVoice Shield / Break-Out Kit: This Section is under Construction!
Have you ever wished you could just add speech to your robot that didn't require large expensive external boards or complicated hard-to-write software? The RoboVoice Shield Break-Out kit is probably just about as easy as it can get without costing you a lot of time coding in complicated speech codes to just tell you its responding to your commands. The RoboVoice Shield is an audio shield for the Arduino that allows you to add synthesized speech effects to your Arduino projects. It could be used in many different ways:  a talking clock, DIY talking GPS, talking robots, motion based alarms

The speech sounds very much like the speech from our SpeakJet Shield, with a "male-robotic" quality to it, but you can say anything you want, on the fly!

This kit uses the RoboVoice IC mentioned in Servo Magazines' Novemeber 2012 "Talk is Cheap" article by Eric Ostendorff. This is THE board we developed in collaboration with Ken Lemieux of Speechchips.com (the developer of the RoboVoice IC itself)! We have put in what we learned from our earlier SpeakJet Shield kit, our user suggestion and wishes lists into the development of this kit. We believe this to be one of the easiest to program TTS boards available. This kit has been designed with flexibility in mind - it is not only a stackable Arduino shield compatible board but it has also been designed to work as a break-out board for the RoboVoice IC with its own built-in 3.3v power regulator and an on-board 1W audio amplifier. Since we had a little unused space after we added in the 3.3v power supply and the audio amp, we added a prototyping area onto the board for adding your own processors or communication ports! Whether you use it as a stack-on Arduino shield, or as a breakout for adding to your Stamp, PicAxe, TI or Raspberry Pi robotics project, or whether you choose build your own processor onto the board itself is up to you! The Prototype area also includes connections for +5v, 3.3v, and GND.

With the RoboVoice Shield , Your robotic projects can speak to you, giving you indications of alarms, warnings, alerts, conditions, levels, whatever you can dream up! The RoboVoice Shield is a self-contained voice synthesizer, The RoboVoice IC used in this shield uses a 3.3V DsPIC with a built-in 16-bit 16kHz digital analog convertor to synthesize a male robotic voice.  A 1 watt audio amplifier and a 3.3V voltage regulator IC and a handful of other parts is included in the kit providing you with a complete single board speech synthesis solution. The 800+ rule TTS (text-to-speech) algorithm on the RoboVoice IC does a very good job of pronouncing most English words and can be made with a little creative mispelling to say anything. And with just a few additional 2-3 letter commands can be easily coaxed into singing as well!

The RoboVoice Shield / Break-Out is currently being offered as either a bare PC board only OR as a complete kit (which includes the RoboVoice PC board, all components, and a speaker kit). These shields are kits... Arduino (or other microcontroller) and assembly tools are NOT included. It is highly recommended you have some experience with electronic assembly, and a some experience programming the microcontroller of your choice (whether that is Arduino, PicAxe, Stamp, Propellor, Rasberry  Pi or other device) before you tackle this kit! Some simple examples are given in my tutorials on this kit, but you need to know how to program your device in order to make the best usage of this kit!

Key features:

  • Arduino compatible shield footprint
  • Output is mono, into L and R channels, standard 3.5mm headphone jack and a connection for a speaker that is switched on when the headphones are unplugged. Either headphones or a small amplified speaker can be plugged into the headphone jack!
  • Stackable! The RoboVoice Shield is easily stacked with other Arduino shields.
  • External GPIO "break-out" connections have been added for use with microcontrollers other than the Arduino (PicAxe, Stamp, Propeller, Raspberry Pi, etc).
  • Additional I/O connections have been added so that the default RoboVoice Shield connections to Arduino digital pins 5,6, and 7 can be easily re-wired anywhere on digital pins 0 thru 13 to avoid pins being used by other Arduino shields. This was added to make it easier to resolve I/O conflicts with other stacked Arduino shields.
  • The RoboVoice Shield has a very light I/O and memory footprint. Programs using this shield can often be written with only a few lines of code! This does not require most of your Arduino's memory resources like software-based speech synthesizers.
  • On-board 3.3V power supply! 5V is supplied to this board from the Arduino or through the 5V connection on the external GPIO connector. It is regulated to the 3.3v needed for the RoboVoice IC.
  • A level-shifter circuit is also included on-board to protect the RoboVoice IC from bad voltages from 5V logic levels used on many 5V microcontroller devices.
  • On-the-fly speech synthesis. An 800+ rule TTS (text-to-speech) algorithm on the RoboVoice IC translates English text sent to it on the fly - offering real-time speech just as you send it.
  • RoHS Compliant - The components used in this kit were chosen to not contain lead, mecury, cadmium or other hazardous materials in order to minimize environmental impact when recycled. In order to satisfy RoHS standards in the EU, a lead-free solder should be used for assembly (this is left to the user/purchaser as we do not at this time sell fully-assembled kits).
 Skill level: intermediate

It is expected you have some experience with building electronic kits and with programming the Arduino. Due to the sensitivity of some of its components, the RoboVoice Shield is not suggested as a beginning kit. Any kit parts made inoperable by improper installation or use may be replaced at retail cost.

A Quick Tour of the RoboVoice Shield

RoboVoice Shield v1.2 & v1.3
 (Click on Photo to enlarge)

RoboVoice (SPO-512) IC - Ascii text sent to it are converted into speech.

Audio amplifier - amplifies the sounds output by the RoboVoice IC to level strong enough to drive a speaker or headphone.

Earphone Jack - a standard 3.5 mm jack into which a headphone, speaker, or external amplifier can be plugged in to listen to speech.

Speaker connection - an external speaker or amplifier may be connected here. It is disabled when the earphone jack is in use,

Power LED - indicates when power is applied to the shield break-out.

"Speaking" (Busy) LED - indicates when the RoboVoice is speaking.

Reset Button - press to reset the Arduino and the RoboVoice Shield.

3.3v regulator IC - this is used to convert the incoming 5V power to a 3.3V regulated power used by the RoboVoice IC.

"Prototyping" area - an area of the board providing a standardized .1" spaced grid for adding/building your own circuitry onto the RoboVoice board. Nearby power connections offer easy access to +5V, +3.3V, and GND.

User Configurable digital I/O connections: - connections on the board allowing you to reconfigure which I/O pins are used on the Arduino for the RoboVoice Shield. This was added to help you to easily resolve I/O conflicts with other stacked Arduino shields!

"Break-Out" GPIO connection - this is a standardized (Parallax-style) GPIO interface connection allowing you to use microcontrollers other than the Arduino with RoboVoice Shield. If you can create a serial connection with your micro, you can interface to the RoboVoice here...


Dimensions                      2.7 x 2.1 inches (standard Arduino footprint)
Input voltage from Arduino      5V

Current draw                    ~30 mA
Speaker impedance               8 ohms
Speaker power output            ~0.6 watt
Arduino pins used               +5, Gnd, Reset, Digital 5, Digital 6, Digital 7 (see note 1 below)

Note 1: RoboVoice Shield v1.1, v1.2 may not be compatible with shields using these digital pins! Other digital pin configurations are possible with simple user modification required.


The RoboVoice Shield is compatible with Arduino UNO, Duemilanove, Diecimila and many other Arduino clone boards. The RoboVoice Shield should be compatible with shields that don't exclusively use digital pins 5,6, or 7. The Arduino Shield Listmaintains a list of Arduino shields and what pins are used by them. This can be useful for determining compatibility with other shields.


Other Pages:

Note The RoboVoice Shield documentation and software examples are under development and may change at any moment without notice...

Version History:

RoboVoice 1.0 - Original PCB design, prototypes sent to beta testers
RoboVoice 1.1 - Revised version of the 1.0 board, added Spkg output to GPIO, reversed GPIO connector for consistency with Parallax designs.
RoboVoice 1.2 - Nudged the parallax gpio connector away from edge of board. Added ability to switch audio amp from 5v to 3.3v arduino source power (3.3v is default.)


The documentation and source files for the RoboVoice Shield Break-Out are released under a  Creative Commons Attribution-Share Alike 3.0 License. All new works based on the information presented in the SpeakJet Shield Basic/TTS documentation must carry the same license. If you wish to negotiate other license terms;  contact me by email.


The Author must be attributed in any future modification or redistribution of the SpeakJet Shield Basic/TTS documentation.


I have taken every opportunity to make the RoboVoice Shield Break-Out documentation as thorough and correct as possible. That said, all of the
information in this website is subject to change or may be unintentionally erroneous. Further, working with electricity and tools always carries the risk of injury, and perhaps death. 

The documentation is intended to assist even a beginning electronics hobbyist to successfully build a RoboVoice Shield, yet still expects a baseline knowledge of tools, electricity and shop safety. I am not responsible for any injury or damage caused by this product or in relationship to this documentation, whether the injury occurs during construction or in conjunction with the operation of the completed device.

Also, the builder/user must understand the RoboVoice Shield device operates only by user controlled programming and is incapable, on its own, of providing warning or alerts of any kind.

If you follow the RoboVoice Shield assembly documentation to the letter and find that your device doesn’t work, feel free to email me. I am happy to help up to a point, and may even offer to repair your assembly (if you are really nice) but please be aware that I offer no warranty or guarantee that this kit will function. I assume no financial liability in the event that you are not satisfied for any reason. 

RoboVoice Shield Break-Out board by Galen Raben is licensed under a Creative Commons Attribution-Share Alike 3.0 Unported License.
Permissions beyond the scope of this license may be available at email DroidBuilder.com. 

© 2012 Galen Raben/DroidBuilder.com