Robotic Talking Turret

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Here I will show you an overview on how to make a robotic talking turret, loosely based off of the turrets from the popular game, Portal. This instructable should help anyone wanting to do an animatronics project.

For more detailed pictures, go to:

This project require some experience with tools, electronic circuits, and maybe a little programming.

Here is a sample video of the turret:
Here is the completed turret:

Let's get started!

Note: This turret was NOT designed to be very good at tracking and shooting - it's more for show than functionality. If you are one of those people who have nothing better to do than criticize other people's Instructables, just close the screen.

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Step 1: Electronics Pt 1: Overview

A "smart" animatronics project needs a brain - in this case, a programmable microcontroller. I will be using a Roboduino, a modification of the popular Arduino microcontroller. The Arduino microcontroller uses easy to use Arduino software that is simple to understand for novice programmers. The Roboduino can be bought from Curious Inventor for around $40, and the various Arduinos can be bought from around $30.

There are plenty of Arduino Instructables here, I would reccomend reading through them if you are unfamiliar with them.

I used a lot of breakaway headers and hook-up wire to make all the connections to the Roboduino.

Step 2: Electronics Pt 2: Sound

Sound is a very important factor of an animatronics project - however, it is usually very difficult to implement with microcontrollers.

So far I have only found one easy to use and cheap sound player for the Arduinos - the wave shield from Adafruit industries. It only costs about $25, much cheaper than other sound playing development boards. Also the coding is fairly simple with the libraries provided by Adafruit.

The disadavanges do pile up, though. It can only play uncompressed WAV files - in mono. It needs 8 connections do the Arduino. It takes a minimum of 10kb of flash on the Arduino - leaving only about 4 or 5kb left on the Arduino for the rest of your code. However other MP3 player boards usually run for around $100, so I just stuck with the wave shield.

I changed the dac.h file in the wave shield library to use analog pins 2-5 instead of the digital pins. I wired up a speaker to the base of the turret.

Step 3: Electronics Pt. 3: LED Lighting

LED lights are cheap and easy to use - and if used in the right way, can add to the asthetics of a project tremendously.

I would reccomend going to eBay and buying an LED assortment. Whenever you need a color, you'll have it on hand. I purchased 7 colors of LEDs, 15 LEDs for each color, for about 6 dollars shipped.

If you want to drive more than one LED on the Arduino, you will need to use a transistor (basic schematic shown in pictures).

The LEDs are connected to the digital ports on the Roboduino, and used the digitalWrite command to turn the LEDs on and off.

Step 4: Electronics Pt. 4: Movement

You need some kind of movement to catch the viewers attention. Servos are a cheap and easy way to incorporate movement into your projects.

Servos can be purchased online or at your local hobby shop, and they usually cost between 10 and 15 dollars. The Arduino software has support for servos, making servo control as simple as a single line of code.

Step 5: Mechanics Pt 1: Materials and Tools

Now that you have a general idea of the electronics you might want to use, you will need something to put them all on to - a frame of some sorts.

The majority of my turret is constructed from Sintra expanded PVC plastic. It can be formed and bent by heating, and is easily cut and drilled with hand tools. To connect the varioius Sintra sheets together, I used right-angle mounts from Budget Robotics - you can pick up about 10 right angle mounts for just a buck or two.

There are a ton of nuts and bolts on the turret, and they all came from cheap dollar-store assortments - very handy and cheap. If quality is important to you, I would reccomend going to a hardware store for your nuts and bolts.

I used the following tools (plus a few other basic ones like screwdrivers or pliers):
Cordless drill
Rotary tool
Hand saw
Heat gun
Soldering iron
Hobby knife

Step 6: Mechanics Pt 2: Gun

I used a cheap wal-mart airsoft gun. It is an AEG (automatic electric gun), so all that is needed to fire it is to put power through the motor.

Before mounting it I cut off any excess plastic to streamline it a little - I followed this tutorial to cut off the extra stuff:

I then made a bigger hopper using an old fruit-2-o bottle.

Step 7:

Not sure how to put it, but I just built the turret. Saw the plastic, drill holes, bolt it together.

Step 8: Programming

Attached is the Arduino program for the demo video shown:

Note that you will need the SoftwareServo library and the Wave shield library.

Step 9: Tracking

The turret needs some kind of brains to identify targets - in this case, a scanning rangefinder.

I used the Stampy method in the link below

Here is a video of the tracking in action:

Step 10: Green: Solar Charged Batteries

Now for the green part: solar charged batteries!

I opened up one of those solar-outdoor light things and found a simple circuit and 3 AA batteries inside! The solar cells would charge the batteries during the day. I replaced the flimsy wires with stronger hook-up wire, and soldered on connectors to the terminals - now when I want to charge the turret, I just have to take the battery outside for a day and I'm set.

Step 11: Have Fun!

There you have it, an overview on how to make a great animatronics project (in my case, a turret.). Have fun!

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    24 Discussions


    3 years ago

    sir have you any video of this project for more clarification . i am very interested to to this project . email me the link at


    6 years ago on Step 2

    RadioShack sells these recording modules: you hit record, do your sound, and when you hit play it plays the sound recorded.


    7 years ago on Step 2

    why don't you use a cheap mp3 player that uses sd cards and wire it up to the arduino board? there are loads of tutorials from instructables


    8 years ago on Introduction

    This is really neat. One question though:

    Where did you get the Portal audio samples? Can you post a link or something? That would be helpful for us users who want to do something like this!


    2 replies

    Reply 8 years ago on Introduction

    If you have the non-steam version of portal, you can go into the files installed on your computer and find all the audio samples.

    You should now try to make it look and sound like one from the game and have the doors swing open when someone sets it off.

    1 reply

    9 years ago on Step 11

    Can u made a tutorial how to make it from the begin??


    9 years ago on Step 2

    do you need sound i just want to make one that fires


    10 years ago on Introduction

    Would it be possible to use webcam instead of stampy method? :D

    Sorry no schematic, though. I didn't use one... just kind of threw things together with the Roboduino. Nothing was complicated, just hooked up some servos, leds, transistors, etc. I guess the wave shield was the most confusing but it's all on the ladyada web site.


    10 years ago on Introduction

    Brilliant work! Well done! This must be the first gun turret I've seen with real character, even if it is taken from Portal, so what, it works great. The Arduino is well coded to give it great character. I was somewhat disappointed though that it doesn't make the loud alert bleeping sound when knocked over, as they do in the game. In Portal it gets all confused and shoots for a short while too before making a shutting down sound - as far as I can remember. Would be great to add that - should be quick to change the wave files, nudge nudge ;-) One thing though, If I'd have programmed it, I would have cut down the random chatter, just not speaking so often to cut down on the annoyance factor. Other than these very little gripes, awesome job!