Hello all! In this Instructable I'll be showing you how to make a robot similar to the "Mobile Arduino Experimental Platform" (MAEP) that I made. It is equipped with two motors that can steer the robot and the ability to see obstacles in front of it with a PING))) ultrasonic sensor. 

With the attached breadboard, you can do more electronics experiments, fool around with different sensors, etc. This project can teach you about electronics, programming, and robotics. It is also a fun toy to entertain younger siblings and pets (just be sure they don't break it!).

Here is a video of what MAEP will do when it is done:

Step 1: Parts

Here's everything you need to make MAEP. I tried to provide links to where you can buy these parts from YourDuino.com, which is the official shop of letsmakerobots.com. EDIT: YourDuino and LMR are now separated and YourDuino is no longer giving money to LMR, however they still have pretty good prices so feel free to shop there.

- Arduino compatible microcontroller. I used an Arduino Uno, so I recommend one if you wish to follow closely along with this tutorial. There are also some Arduino based controllers that are designed specifically for robotics that may be helpful, but you’ll have to find your own method of mounting those. You can buy a copy of the Uno from YourDuino which I believe is completely compatible: http://arduino-direct.com/sunshop/index.php?l=product_detail&p=5

-  Breadboard. Make sure it’s not too big, or else it won’t fit. However, we want it to be as big as possible so we have more room for electronics. This is good: http://arduino-direct.com/sunshop/index.php?l=product_detail&p=168

- A standard old 9 volt alkaline battery (which you can probably find at home), as well as a barrel jack connector to hook it up to your Uno easily (not required, but again, easier):  http://arduino-direct.com/sunshop/index.php?l=product_detail&p=119

- A power supply for the motors. I don’t believe the power supply I chose is the cheapest or best option, so I’m not going to recommend it to you. I used a 4.8 volt rechargeable NiCad battery, but it’s probably easier to just use a 4 AA battery holder (no need to buy a charger that way)

- A bunch of Boe-Bot hardware for the chassis. Unfortunately, you can’t get this from YourDuino, so look at Parallax, the manufacturer’s website. You can choose either to buy this: http://www.parallax.com/StoreSearchResults/tabid/768/List/0/SortField/4/ProductID/304/Default.aspx?txtSearch=boe+bot+chassis which comes with tons of extra components you don’t need (although may be useful someday), or you can buy all the components in the following list from Parallax and no, I’m not gonna provide a link for each one:

Stock # Quantity              Product Name

700-00002            8             Panhead screw, 4/40, 3/8

700-00003            8              4/40 x 3/8" Nut

700-00009            1             Tail Wheel Ball

700-00015            2              #4 Nylon Washer

700-00022            1              Boe-Bot Aluminum Chassis

700-00023            1              Cotter Pin-1/16" Diameter

700-00025            1              Rubber Grommet-13/32" Hole Diameter

700-00028            4              Panhead screw, 4/40, 1/4

700-00060            2              Standoff, threaded aluminum, round 4-40

721-00001            2              Wheel, Plastic, 2.58 Dia, .3 W

721-00002            2              Rubber Band Tire for 721-00001

900-00008            2              Continuous Rotation Servo

- Wire to hook things up will be necessary. Some male-to-male jumpers will do the trick: http://arduino-direct.com/sunshop/index.php?l=product_detail&p=94

- Finally, the PING))) sensor and mounting bracket, so that your robot doesn't kill itself: http://www.parallax.com/StoreSearchResults/tabid/768/List/0/SortField/4/ProductID/563/Default.aspx?txtSearch=ping+sensor+mount

As for tools, all you need is a phillips head screwdriver, a computer, and one of those standard USB printer cables. The Arduino Uno I provided a link for has a cable included. 

Now lets get building!
you can get a sensor from literally ebay or amzon anywhere really
<p>well this is cool</p>
<p>Where can you get a sensor from</p>
<p>Hi..I Want to Kno How Can I Made this using two sensors..in parallel sides.</p>
Need help.. I finished the build but the robot isn't moving however when I remove one of the ground pins then the bot begins to move but only moves in a circle... Anyone know why??
<p>not working waste of time</p>
Please Sent me this schematic
Is there is any youtube video for this project
<p>look at this link : https://www.instructables.com/id/Arduino-Ultimate-Obstacle-Avoiding-Robot/</p>
Help me my ping has 4 pins what to do<br>
<p>look at this link : https://www.instructables.com/id/Arduino-Ultimate-Obstacle-Avoiding-Robot/</p>
I the video the ping sensor also has a servo attached to it
Good tutorial
do you have a fritzing parts placement for this? tnx in advance
<p>Nice tutorial, thanks! Go everything working and now to add the IR sensors. </p>
<p>please help me.</p>
<p>Hey is it okay if I use a Futoba Servo for my ping sensor. The only difference between the Futoba and my regular servos is that the Futoba doesn't go all the way around. It only goes halfway and then stops</p>
<p> You get a lot of problems in the comments but I would just like to say I love this instructable and enjoy you robots!</p>
<p>Hello,</p><p>Is there someone who has the same code but with an 4 pin HC-SR04 Sensor?</p><p>Thanks</p><p>Jelmer</p>
<p>Even I want a code for a 4 pin !</p>
<p>Connect the Trig and Echo pins from your 4-pin sensor both to the same pin (pin 7). The code switches the pin mode between input and output on the fly so it can use one wire for both. The HC-SR04 doesn't care.</p><p>-OR-</p><p>If you don't want to do that, you need to connect Trig to pin 7 and connect Echo to a different pin and change the code to listen for input on that pin instead. </p><p>Untested, but basically:</p><p>* Plug echo into pin 8<br>* inthe code after &quot;const int pingPin = 7;&quot; add</p><p>const int echoPin = 8;</p><p>* change the code after &quot;//Get duration it takes to receive echo&quot; like so:</p><p>//Get duration it takes to receive echo<br>pinMode(echoPin, INPUT);<br>duration = pulseIn(echoPin, HIGH);</p><p>(you could also move the pin mode declarations up top since they're not changing modes any more, but you don't have to)</p>
<p>hi i m surya just connect it to a breadboard after that to the arduino digipin</p>
<p>Hey surya, Dint get you, Can you please explain it ?</p>
hello im just wondering. my left and right servo won't spin 360degrees but it only spin to 180 degrees.. how to make it spin to 360...
<p>A bit late but if you're still confused, you probably do not have a continuous rotation servo. Most servos cannot spin in a full circle and those that can are specially titled as continuous rotation servo. </p>
if you need help n code check here https://youtu.be/rcrzHPu0Q_8
Hello, i made this robot, made all the connections, uploaded the code to the arduino, but nothing happens. I unplugged the arduino, applied power from the 9v battery (via the Vin port thing), put the robot an an open space yet nothing happens. However, if i put my ear up close to it, i can hear a low, humming noise that i /think/ is comming from the servos
Hello,<br>Is there someone who has code for wall follwer in which left turn has higher priority than right using 3 ultrasonic sensors. Plz reply fast. It would be the great help
<p>First thank you all of you,now i am doing fire fighting robot project however i am facing some problem.which is we have to use the photo diode and IR LED rather than ultrasonic sensor for obstacle and distance sensor because of the availability.so please help me if is there a change in any one of the program and the circuit or if you have any idea which you think is you can tell me what i have to do</p>
<p>Is the photodiode and IRLed in one sensor? Like a Sharp IR Sensor (http://www.acroname.com/articles/sharp.html) ?</p><p>If so then it is very comparable to the Ultrasonic sensor, but the target area is very narrow and you may want a sweeping motion in your code that takes multiple readings then move the robot in the longest duration direction. There are many tutorials on the specifics of that sensor. Here are some links: </p><p><a href="https://www.instructables.com/id/Arduino-based-robot-with-IR-radar/" rel="nofollow">https://www.instructables.com/id/Arduino-based-robo...</a></p><p><a href="http://communityofrobots.com/tutorial/kawal/how-make-your-first-robot-using-arduino" rel="nofollow">http://communityofrobots.com/tutorial/kawal/how-ma...</a></p><p><a href="http://www.societyofrobots.com/sensors_sharpirrange.shtml" rel="nofollow">http://www.societyofrobots.com/sensors_sharpirrang...</a></p><p>Hope that helps.</p>
<p>i made it but it kills the battery too fast can someone tell me what can i do to make the battery last longer</p>
<p>You will need batteries that have a higher mAh (milli-Amp-hour) rating. Basically same voltage but bigger charge. OR You could add more batteries in parallel. Basically add two or more of the same batteries that you have by connecting positive to positive and negative to negative. This will double the charge but keep the same voltage. Look online for your battery type. </p>
<p>hey... i am new here..... can anyone tell me about the servo under the ultrasonic sensor.... plzzzz fast...</p>
<p>It seems to be an ordinary un-modified servo. It is used in conjunction with the ultrasonic servo to determine distance in three different angles (left, right and center) Your code will move the robot towards the angle that has the longest PING time, which has more open area.</p><p>I believe that the author did not include this third servo in the materials list. Six months isn't fast but I hope it helps.</p><p>:P</p>
<p>reply fast guys ....... its urgent !!!!!!!!!</p>
<p><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/ZNwRAlUqKRM" width="500"></iframe></p><p>bot with ping added :)</p><p>Thanks again </p>
<p>hello , its a very nice robot ,<br>we have a project and we are new to almost every thing :) <br>but am gathering information any way<br>our robot going to hold objects , so i want it to not turn around when it reach it , instead , to stop , and hold it using magnatic or sth .. <br>can you please help me with the code<br>and how to stop when it reach a certain distance from the object , can we do that ? thanks a lot </p>
<p>can i replace servo using dc geared motors??</p>
Hi, <br>Could you help me with the problem I'm having with my robot PLEASE. <br>Basically I've used the code you have posted, but it didnt work so I made bit change but still it didnt work, the problem is my the servo with ultrasonic sensor on it keep on spinning left and right constantly even tho there is no obstacle in front. <br>And also the robot goes few steps forward and again spins the servo with the ultrasonic sensor. <br>By the way i'm using ultrasonic sensor with 4 pins (HC-SR04) <br>I would really appreciate, if u could correct it <br>Cheers <br> <br> <br> <br> <br>/*MAEP 2.0 Navigation <br>by Noah Moroze, aka GeneralGeek <br>This code has been released under a Attribution-NonCommercial-ShareAlike license, more info at http://creativecommons.org/licenses/ <br>PING))) code by David A. Mellis and Tom Igoe http://www.arduino.cc/en/Tutorial/Ping <br>*/ <br>#include //include Servo library <br> <br>const int RForward = 0; <br>const int RBackward = 180; <br>const int LForward = 0; <br>const int LBackward = 180; <br>const int RNeutral = 90; <br>const int LNeutral = 90; //constants for motor speed <br>const int trigpin = 7; <br>const int echopin = 3; <br>const int dangerThresh = 10; //threshold for obstacles (in cm) <br>int leftDistance, rightDistance; //distances on either side <br>Servo panMotor; <br>Servo leftMotor; <br>Servo rightMotor; //declare motors <br>long duration; //time it takes to recieve PING))) signal <br> <br>void setup() <br>{ <br> rightMotor.attach(11); <br> leftMotor.attach(10); <br> panMotor.attach(6); //attach motors to proper pins <br> panMotor.write(90); //set PING))) pan to center <br>} <br> <br>void loop() <br>{ <br> int distanceFwd = ping(); <br> if (distanceFwd&gt;dangerThresh) //if path is clear <br> { <br> leftMotor.write(LForward); <br> rightMotor.write(RForward); //move forward <br> } <br> else //if path is blocked <br> { <br> leftMotor.write(LNeutral); <br> rightMotor.write(RNeutral); <br> panMotor.write(0); <br> delay(500); <br> rightDistance = ping(); //scan to the right <br> delay(500); <br> panMotor.write(180); <br> delay(700); <br> leftDistance = ping(); //scan to the left <br> delay(500); <br> panMotor.write(90); //return to center <br> delay(100); <br> compareDistance(); <br> } <br>} <br> <br>void compareDistance() <br>{ <br> if (leftDistance&gt;rightDistance) //if left is less obstructed <br> { <br> leftMotor.write(LBackward); <br> rightMotor.write(RForward); //turn left <br> delay(500); <br> } <br> else if (rightDistance&gt;leftDistance) //if right is less obstructed <br> { <br> leftMotor.write(LForward); <br> rightMotor.write(RBackward); //turn right <br> delay(500); <br> } <br> else //if they are equally obstructed <br> { <br> leftMotor.write(LForward); <br> rightMotor.write(RBackward); //turn 180 degrees <br> delay(1000); <br> } <br>} <br> <br>long ping() <br>{ <br> // Send out PING))) signal pulse <br> pinMode(trigpin, OUTPUT); <br> pinMode(echopin,INPUT); <br> digitalWrite(trigpin, LOW); <br> delayMicroseconds(2); <br> digitalWrite(trigpin, HIGH); <br> delayMicroseconds(10); <br> digitalWrite(trigpin, LOW); <br> <br> //Get duration it takes to receive echo <br> <br> duration = pulseIn(echopin, HIGH); <br> <br> //Convert duration into distance <br> return duration / 29 / 2; <br>} <br>
<p>Are you using a continuous rotation servo for the PING sensor? You need a normal servo to get proper degrees for that servo. Continuous rotation servos merely spin cockwise, counter-clockwise, and stop using the values 180, 0, and 90 respectively.</p><p>The code looks fine and wouldn't cause the symptoms you describe.</p><p>:P</p>
Hi, this seems like it should work. Google how to use the Arduino serial port if you don't know how, then print out the duration variable in a loop. Test different distances, and see if the sensor is returning the right distance from the obstacle.
Hello all <br>I was thinking about making this awesome robot. But after reading the whole article and the code i got confused with the operation of the two servos that drive the wheels. <br>As far as i know, a contineous rotating servo has lost its control over the amount of degree to rotate. Then how can the wheel servo rotate 90&ordm; and 180&ordm;?
<p>With continuous rotation servos it acts more like a speed control. The servo commands execute until the potentiometer in the servo reaches a certain resistance that equals that degree then stops. The servo will never reach that resistance because the potentiometer is essentially disabled. So 90 degrees is center, 180 degrees is turn right (I think) and 0 is turn left.</p><p>I think the solutions for degrees of movement of the robot involve time and/or light sensors like photoresistors, on the the wheels to calculate degrees.</p>
<p>Hi, im trying to do this exact project and in addition to this i would like to add sound source tracking. could you anyone help?</p>
<p>Experiment with two microphones on Arduino analog pins and compare the two inputs similar to photo-resistors for light.</p>
<p>I notice you don't use a motor shield or diode protection on the breadboard. Isn't a safeguard needed against an inductance induced power spike when the servos are stopped? Also wouldn't the load of the two servos be very close to the maximum the Arduino can handle without being damaged? </p>
<p>le servo-moteur coute vers 10 euro en tant que le moteur simple coute 3 euro , tu sais pourquoi ? <br>parce que le servo-moteur est d&eacute;j&agrave; &eacute;quip&eacute; d'un moteur shield et protection complete dedans c'est pour cela il y a aucun risque a se montage :) </p>
<p>HI! :) mine is working pretty good thanks to you. and in fact i made some changes and it was perfectly working to..</p>
<p>Is it possible to make this with the Dagu Rover 5 Tracked Robot Chassis?</p>

About This Instructable




Bio: A kid who is passionate about robotics, electronics, and computer programming.
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