Easy Built Biped Bot


 After I was finished building my first “real” robot, I took the chance of competing with it in this SoR contest.

The robot is called iBB – Eye Biped Bot, and is a biped bot. Although the electronics isn’t the most advances, this is a good beginner’s project for everyone who wants to build up some basic robotic skills for cheap money.

The robot is controlled by the keyboard from the computer, so it’s like a RC robot but instead of Radio Controlled – It’s Computer Controlled (by USB).

 The price is ~57$ (57, 9$) so basically everyone can afford it.

!!!The Source code can be found at the buttom of the side, as an attachment!!!



Part List:

-         Wood boards – Had it

-         Servo controller – 17,95$

-         USB-to-serial adapter – 17,95$

-         Servos x2 – 16$

-         USB A to mini B cable – Had it

-         Support wheel – 5$

-         Candy eyes – 1$

-         Toy mouth – Had it


Total: 57, 9$



Building the chassis:


Step 1: I got the wood box from a room with a bunch of other things that was going to get tossed anyway, and I covered it with black duck tape for colour and some other tape with a green and yellow pattern to add some style.

YOU don’t need to use a box like this, you can use anything you find that can fit as chassis to your robot, but it should be about the same size

 (13cm x 18cm) so the electronics can fit inside without having to modify the chassis. One of the sides of the box should be able to go on and off; so you don’t have to tear your entire robot apart each time you need to modify anything inside.


Picture ->  http://www.rson.no/ibb_pic1.htm


Step 2: After finding you a chassis, you’re next step is to make two equal holes through the side of the chassis. This is where the servos will stick out, and the legs will be attached. Make sure to measure up the size of the hole, depending on the size, and shape of your servos. 

Picture ->  http://www.rson.no/ibb_pic3.htm





Adding the electronics:


Step 1: Start by gluing the two servos by the holes so the tip (the rotating part) sticks out, for example hot glue like I used.


Picture -> http://www.rson.no/ibb_pic18.htm



Step 2: Now take two sets of batteries: A 6 volts battery pack, example a pack with 4 AA batteries and a 9 volts battery. The 6 volts will power the server controller and the 9 volts will power the servos. Attach these with a good duck tape as I did, or you can use your own way if you have any good ideas. I used duck tape so I wouldn’t permanently attach the batteries, so they could easily be removed when I needed to change batteries.


Picture -> http://www.rson.no/ibb_pic19.htm


Step 3: Now we will attach the servo controller. If your chassis size is right, it should be a little more space in your chassis, find a spot to attach your servo controller. There should be a little hole going through the servo controller, take a small screw and screw the servo controller on. Make sure the screw isn’t to long; you don’t want it to stick out of the chassis.


Picture -> http://www.rson.no/ibb_pic7.htm

Step 4: Now its time for the final piece: The USB-to-serial adapter. This is the smallest part and it has no hole through it for attachment, for this very reason there might be smart to attach it with something safe like tape, to avoid injuring any electronic components on the board.  


 Picture -> http://www.rson.no/ibb_pic6.htm


Putting everything together:



Now its time to put all the parts together to make the robot able to work.


Step 1: Start by plug in the two cables from the servos into any of the I/O pins from 0-7.


Step 2: Now let’s solder the servo controller and the USB-to-serial adapter together and the batteries onto the servo controller board.. Watch the pictures underneath and follow my guidance to connect them together: (CAUTION: watch out that you’re soldering do affect more then just the pins your suppose to solder, this can end in circuit failure)


Here you can see how to set the electronic parts together:



 4-6 Volt on the red and black dots     -    5-16 Volt on the yellow and black dots.


Connect the servo controller and the USB-to-serial adapter together:

-One wire goes from the Logic-level serial input to the RED dot.

-The other wire goes from the GND to the GREEN dot.

Picture 1 - Servo Controller -> http://www.rson.no/ibb_pic4.htm

Picture 2 - USB-to-serial adapter -> http://www.rson.no/ibb_pic5.htm




Wrap things up


At this point, everything should be connected. Time to get your USB A to mini B cable, connect it into your USB-to-serial adapter input, and into you computers USB port.

For your USB-to-serial adapter to work properly you should install the USB-to-serial adapter driver, you can do this by following this page: http://www.pololu.com/docs/0J7

The code I will post is written in C++. A good and free program to drive this code is the Dev-C++, if you wish to download it you should visit they’re webpage (Google it).

Make a whole in the back of your robot where the USB A to mini B cable sticks out. The USB connection in the robot can be connected at all times, so you don’t have to open the robot for each use.


Picture -> http://cfs4.tistory.com/upload_control/download.blog?fhandle=YmxvZzY4NTAyQGZzNC50aXN0b3J5LmNvbTovYXR0YWNoLzAvMDUwMDAwMDAwMDAwLkpQRw

Add leggs and support wheel


Cut two boards of wood at the length of ~10 cm. Screw or glue the accessories following in the servo pack onto the legs (The thingy that’s going outside the metal pin rotating at the head of the servo). And make a round shape of some easy fabric like carton and add it to the underside of the feet (to give some stability). Now you can easily attach or unattach the legs to the robot whenever you want.

Picture -> http://www.rson.no/ibb_pic9.htm

Make another piece of wood at any length you may want, and attach it to the underside of the robot chassis, so it sticks out towards the back of the robot, as you see on the picture. To this piece of wood, you can screw the support wheel onto (make sure that the wheel is big enough to reach the ground!)

Picture -> http://www.rson.no/ibb_pic8.htm

Last thing you have to do is to compile and run you’re code, or take mine and use it, your choice!


Final result pictures:

Picture 1 - No mouth: http://www.rson.no/ibb_pic11.htm

Picture 2 - http://www.rson.no/ibb_pic12.htm

Picture 3 - http://www.rson.no/ibb_pic13.htm

Videos (Click on the links to go to youtube and watch my robot videos):

Video #1: Code testing

Video #2: Balance Testing


Difficulties I met:


The only difficulty I met was that I met some problems while running the code, but it was only because I hadn’t given the right COM number (USB port number), so therefore, for you to avoid the same mistake you should set you COM number where the number: 1 – is showed in the following phrase:

 comPort=openPort(1);//***PUT YOUR COM PORT NUMBER HERE!***


Also if you’re having problem with compiling the code, you can either contact me, or you can try deleting every phrase/edit them as the error message says when your compiling.

Time spent

  • Research: 15 Hours
  • Building/modifying the chassis: 2 Hours
  • Mounting electronics: 2 Hours
  • Coding: 3 Hours
  • Total time spent: 22 Hours




ibb source code.zip2.11 KB


You should shrink down the

You should shrink down the pics a bit and embed them into the page (instead of linking).


For attaching batteries, try out velcro, sooooo much better than tape. I like your hinge idea to open/close the box!


Anyway, you've learned a lot since joining SoR! And your video is hillarious! =)