This shows you how to build an arcade style crane game out of scrap parts.  The basic parts are: a motorized assembly that raises and lowers a claw,  a track for the assembly to move around on, and a ctontroller with some electronics. 

October 2013
Actual claw on tindie.com fundraiser 

*** September 2013  **
I have a project running on tindie.com   for a real claw machine kit.

Here is a video of the machine in action.

Video -

Emma after some practice-

Controls -

Pick up and drop -

Overview -
I like to document my work as I go along, so this instructable contains multiple versions with varying components.   I think that this is useful because it seems unlickkly that you would happen to have all the same scrap peices as I do.  I have also tried to show how to build a moderatly complex system by  bulding one peice at a time and then combining them.  By keeping things modular you are able to swap out large peices without having to rebuild the whole thing. 

Here is a rough outline:
     - Get each motor working by itself,  I used a joystick with potentiameters to control the motors, one POT per motor
     - Get all the motors working at once - by wiring all the motor drivers to the Arduino at once and combing the control codes, we are able to run everything at once.  This same setup will be used l to control the whole machine.
     - Build a small test rig with just one axis - It is easier to work on something that you can put on a bench top then it is to work with something mounted the ceiling.  So I will show you how to cobble together a test set-up that will let us work out some of the details without having to build a large rig.
     - Build a large rig - once everything is working on the test rig, we can go ahead and make it bigger.  This required some different materials, but the wiring, code, and motor setup don't nned to change. 
    - Test and improve  - Once the system is working it is easy to see things that can be improved.  I wound up replacing the original joysticks with a larger controller from a kids game.  The whole thing is pretty flexible so there is alot of room for modification and impruovemnt.

Parts - 
Most of the project is built with salvaged computer parts.   Here is a list of parts that you could salvage or buy. 

Power supply - I used a power supply salvaged from a server.  There are good instructions for hacking one of these here http://reprap.org/bin/view/Main/PCPowerSupply  I also pulled a 12volt power supply out of a printer that would have worked well.

Motors -  At least 3 motors are needed.  I used 2 DC motors and a pretty big stepper.  The DC motors are both pulled from an Epson Printer/Scanner.  The stepper is a NEM23 from Keling Technology.  A smaller one would be fine.   You can get one here http://www.sparkfun.com/commerce/product_info.php?products_id=9238.

Drivers -  You can build, buy, or salvage drivers for the motors.  Buying is the easiest and they are not two expensive. I used a  steppper driver and the DC motor driver from the RepRap Gen2 electornics.  The DC motor driver is here - DC Motor Driver v1.1 Kit  http://store.makerbot.com/electronics/electronics-kits.html.   Sparkfun as a good stepper driver here - http://www.sparkfun.com/commerce/product_info.php?products_id=9402

This motor sheild from Adafruit would work well - http://www.adafruit.com/index.php?main_page=product_info&cPath=34&products_id=81

Microcontroller -   The Arduino platform is fun and easy to use.  http://www.arduino.cc/  I used the
Arduino Duemilonove with a hefty screw sheild  http://store.makerbot.com/electronics/electronics-kits/arduino-breakout-shield-v1-4-kit.html

Controller - I started with thumb joystick controllers like  on a PS2 - but I found that a controller from Leap Frog Baby worked out better. http://www.amazon.com/LeapFrog-10210-LITTLE-LEAPS-PLATFORM/dp/B000EIV1OM

Claw - The claw is made from mouse shells and strips of plastics cut from a printer housing.

Wiring - Most of the wiring is discarded cat-5 network cable

Track  - For the test rig I used wooden tracks, for the larger set up I used metal J-trim 1/2" x 10' - this was in the drywall section of home depot - it is the only thing I bought specifically for this project.

Step 1: Control a DC motor with variable resistor

The first thing we will do is to get each motor working with a controller. 

Use a joystick with potentiameter to controll the speed and direction of a DC motor. 

This will be used to:
                         - raise and lower the claw
                         - open and close the clow

Hardware chain:
Joystick (potentiameter) -> Arduino with code -> DC motor driver V1.1 (make.rrf.org\dcmd-1.1) - > motor

Relies on: http://www.reprap.org/bin/view/Main/DC_Motor_Driver_1_1#Wire_up_test_devices

Here is the arduino code:   
          note: this only runs one DC motor

//******* POT to control a DC motor speed and direction ******//

// define pins and variables
int potPin = 2;    // select the input pin for the potentiometer
int val = 0;       // variable to store the value coming from the sensor
int j = 0;
int Dir_A = 4;
int Speed_A = 5;

void setup() {
  pinMode(Dir_A, OUTPUT);
  pinMode(Speed_A, OUTPUT);


void loop() {

// Read location of joystick and calculate the distance and from center
  val = analogRead(potPin);    // read the value from the sensor
  j = val - 517;  // 517 is center positions - how far from center
  j = abs(j);      //absolute value

// put some bounds on j to keep PWM values useful
// below 100 the motor won't move and PWM max is 255
  if (j >= 510){
    j = 510;  //the most the PWM pin can do is 255
  if (j <=200 && j>=10){
    j=200;    //below 100 PWM the motor makes a high pich sound and does not move
  if (j <=10){
    j=0;    // below 10 the joystick is very close to center
 //Run DC motor A based on analog input from joystick
  if (val >= 520){
    digitalWrite(Dir_A, HIGH);  // other direction
    analogWrite(Speed_A, j/2); // PWM out (divide by 2 because max is 255)
  if (val <= 510){
    digitalWrite(Dir_A, LOW);  //
    analogWrite(Speed_A, j/2); //

  if (val <=520 && val >= 510) { 
    analogWrite(Speed_A, 0);  // turn off if the joystick is in the center

// print values for debugging
  Serial.print(val);        // send numbers to PC so you can see what it going on



<p>could u give me wiring schematic.I can not tell from your picture.thanks</p><p>my mail:eddie5492001t@yahoo.com.tw</p><p>One more question.what does POT mean?</p>
<p>Hi, nice project!<br><br>i was wondering if you can do this with two stepper motors?<br>and what would the circuit look like?<br><br>thanks in advance!</p>
<p>i didn't find any diagram for this project ...</p><p>can you help my to get diagram</p>
<p>How did you make the Funzo?? </p>
So Marc, this is almost inline with a project I'm starting. I would like to create a 2 servo mechanism that controls pitch and yaw for a telescope. I have a couple of easy step controllers and a joystick ( 27800 2 axis ), I'm new to arduino so I am unsure if I need to incorporate that into the design - such as the coding. Have you come across a design for this sort of project? Thanks <br> <br>bill
could you have run a DC motor in place of the stepper motor with the same code which is used to run the DC motor?? <br>please reply <br>ps: excuse me if i am being lame n stupid
help me <br>can you send me the code for two stepper; Stepper X, Stepper Y for pan and tilt http://www.youtube.com/watch?v=ZulNF2enrd0 <br>i have 2 stepper motors, 2 EasyDriver, Arduino uno and Joistick <br>black_daysro@yahoo.com <br>thanks in advance ;)
http://www.robofun.ro/shields/driver-l298-asamblat <br> <br>i heve this type of motor shield.
You should be able to add a second copy of the same code, subing the pins being used for the second motor.<br><br>Try looking at steps, 3, 15, 16<br><br>Step 3 shows the code for a stepper (which you probably dont need).<br>Step 15 shows code for a second dc motor.<br>Step 16 shows these three peices of code combined.<br><br>Good luck!
i have that motor shield, but i can't make the skech to drive 2 motors. <br>I use youre sketch and it works fine, i don't know how to modify for 2 motors.
Hi. <br>what i need to change, add to drive two dc motors (speed and direction)? <br>please help. <br>thanks.
I think you are looking for an H-bridge circuit. Also - I recomend the motor sheild from adafriut for things like this.
sorry i forgot to say : As you know the two POTs will be the joystick ;)
yeah me too i have to control two steppers which have 20 n.m torque '' big motors '' and i have the stepper drivers. <br>the motors are installed in a 4 wheeler cart. <br>i made a code to control the cart forward and backward using the motors+drivers+Arduino uno+potentiometer <br>and then i made another code without the potentiometer <br>using 3 Arduinos ( 1 master and two slaves) each slave is connected to a motor <br>the code is to apply speed to one of the motors for ex 10 rpm and the other motor <br>5 rpm .. just to make the cart turns left or right ... <br>THE QUESTION NOW WHAT IS THE CODE FOR THE STEERING USING THE POTENTIOMETER ?? <br>there will be 2 POTs one for steering and the other for moving. <br>PLEASE HELP !!!
Hello,<br><br>I need your help, I'm doing a project similar to yours, a pan tilt head and I need to control two stepper motors with a joystick.<br>Can you help me with the code? How would two stepper motors?<br><br>I'd appreciate if you can send photos or a wiring diagram.<br><br>Thank you very much.
Do you have to use stepper motors? <br> <br>There are alot of examples of pan-and-tilt using hobby servo motors. <br> <br>Here is an example of pan/tilt using servos and joystick: http://www.practicalarduino.com/news/id/411 <br>the code is here: https://github.com/practicalarduino/PanTiltControl/blob/master/PanTiltControl.pde <br> <br>spark fun has parts: http://www.sparkfun.com/products/10335 <br>
Yes, I need to do it with stepper motors, is difficult to code for two engines?
Yeah -- hobby servos have built in feedback, you just need to tell them the angle and they go. If you use stepper motors you need a circuit to drive the motors and some sensors to get feedback on the position of the motors. On the other hand, stepper motors are usually sturdy with more power; so it might be worth it.<br><br>Good luck!
Thanks for responding, <br>I like to use stepper motors because they have strength and are accurate. Project where you use your joystick, you use a stepper motor, could you help me with the code to use 2 stepper motors? <br>I know nothing about programming, so I ask for help. <br> <br>Thanks for everything, <br> <br>Greetings.
I love this! Maybe you could remount the joystick on the ps2 controller?
wow my family broke my pinball machine hey maybe claw machine next has top be tougher
Incredible! Thanks for sharing, how would you do it to make it &quot;stiffer&quot;? Like the arcade games. Thanks!
OMG its funzo from the simpsons
Great Instructable - congratulations! One quick question: would it maybe make more sense to use a machine screw for the center of the claw, rather than a wood screw? For one thing, you don't risk drilling a hole in the object you're picking up. :-) Second, the wood screws have decreasing diameter near the tip, which might make the mechanism slip. Finally, machine screws could give you finer and better control due to the diameter thing and typically more threads per inch. Again - GREAT job!!
COOL&nbsp;<br /> <br /> the kids&nbsp;are so adorable!!!
&quot;writhing funzo's in my sack, makes me happy, makes me hurt my back&quot;<br />
&nbsp;i KNEW it was funzo. i was just thinking: that doll looks soooo familiar....
Any interest in a Crane Game kit?<br /> <br /> It would be&nbsp;an Arduino sheild with a Joystick, Buttons, and Motor Drivers.<br /> <br /> I started using BatchPCB.com last night and boy is it fun!<br /> <br /> <br /> <br />
&nbsp;We need an instructable on how to make that helmet next!
Yeah - until then you'll have to go to pre-school to learn that one!
&nbsp;Have her teach you, and make an instructable at the same time. That would be cute.
Thanks- that's a great idea!
Ive got another idea.&nbsp; Why dont you set up four motors, one in each of the corners of the room, which act as pullies?&nbsp; You can control the precise position in all three axies, and have more stability.
<em>Why dont you set up four motors, one in each of the corners of the room, which act as pullies?<br /> </em><br /> You could certainly try this - but it sounds a bit tricky.&nbsp; I've had better luck with very short drive trains.&nbsp;&nbsp; In this project I've avoid gears and belts as much as possible.<br /> <br /> -Marc
You can do that, but it is not necessary.&nbsp; It only takes three strings and a weight at the end of the three connected strings to ensure stability.&nbsp; One extra motor would make the crane capable of moving all over the room though.
<p>Gotcha - that is an intersting idea.</p>
.How do you think this would be like in an arcade cabinet?<br />
<em>How do you think this would be like in an arcade cabinet?<br /> <br /> </em>Awsome!<br /> <br /> It is fun to cheat - so I would leave out the glass.<br />
Really cool. I&nbsp;like the idea too! Makes me want to take apart my computer now. XD
I'm not sure which is better the project or the videos! Cool idea, thoughtfully executed and well documented. When will it be strong enough to pick up something useful like say.. a bottle of beer? ;-)
<br /> I'm a Weiner!!!<br /> <br /> Wanderwolf - I'm going to put a link to your Xmega board with USB bootloader.&nbsp;<br /> <br /> Here it is - <br /> <br /> <a href="http://www.bostonandroid.com/EVAL-USB-256.html" rel="nofollow">http://www.bostonandroid.com/EVAL-USB-256.html</a><br /> <br /> <br /> -Marc
Congrats Husband on your big win. I&nbsp;can't wait to use &quot;my&quot; new netbook. <br /> Oh, and you still need to fill in the holes in the doorway. <br />
&nbsp;parab&eacute;ns pelo seu projeto, gostei muito da sua criatividade de usar materiais alternativos para constru&ccedil;&atilde;o.
<span class="short_text" id="result_box"><span style="background-color: rgb(235,239,249);" title="Thank you, I am glad you enjoyed it!"><font size="5">Obrigado, estou contente que tenha gostado!</font></span></span>
The instructables I enjoy most are the ones that are comprehensive, well detailed, and even show the rush of the maker in their notes.&nbsp; e.g. misspellings, etc.&nbsp; I'm not complaining.&nbsp; In fact, I'm extending a kudos.&nbsp; This was an A++ instructable.&nbsp; I don't know a lot about microcontrollers.&nbsp; I&nbsp;guess I'm afraid of jumping in and screwing up whatever I'm trying to do.&nbsp; But your instructable has inspired me to get an Arduino and start exploring.&nbsp; Love the work you've done.&nbsp; You've illustrated that robotics is in all aspects of our lives and we don't even think about it.&nbsp; On a side note, your &quot;little helpers&quot; are adorable. :-)
Great thanks!<br /> <br /> <a href="http://www.Sparkfun.com" rel="nofollow">www.Sparkfun.com</a> and <a href="http://www.adafruit.com" rel="nofollow">www.adafruit.com</a> are good sources.<br /> <br /> The &quot;<span id="btAsinTitle">Getting Started with Arduino&quot; book by&nbsp;<span class="ptBrand">by <a href="http://www.amazon.com/Massimo-Banzi/e/B00355CV22/ref=sr_ntt_srch_lnk_1?_encoding=UTF8&amp;qid=1267386793&amp;sr=1-1" rel="nofollow"><font color="#003399">Massimo Banzi</font></a> and Banzi Massimo</span><span class="binding">&nbsp;</span>&nbsp;is worth getting as well.<br /> <br /> -Marc</span>
I can't believe your wife let you put this in your doorway! And she even helped you with it. :P<br /> <br /> Awesome project, by the way! Looks like fun. :) Now make one with two axes!<br />
It does have two axis... Y and Z!<br /> ( y = left/right&nbsp; Z = up/down)<br /> <br /> But yeah... go for a 3-axis x / y / x ! <br /> <br /> Build the gantry... one track on the first wall, the second on the other... do the whole room! (Evil grin)<br />
Y and Z? Two axes? That's ridiculous!<br /> <br /> Everybody knows X is left and right and Y is up and down!<br /> <br /> Get your facts straight. :P<br /> Only joking, of course. Once again, nice project.<br />

About This Instructable


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Bio: Married to Domestic_Engineer (but I call her Meghan).
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