Building a robot with four legs Arduino. Print
Drew working on the Arduino Walker

Arduino Simple Walker

Drew working on the Arduino Walker

We recently had some parts designed through Ponoko.com, on that order we threw in some pieces for a simple arduino walker. Over on Instructables.com, we had seen an awesome pattern for a 4-legged, 2 servo simple walker design. If you have younger kids who are interested in robotics, electronics, crafts, etc. this is a great little project to introduce them to the Arduino. As a bonus, Ponoko.com has given us a coupon that you can use that will give you 50% off your making order! Coupon at the end of this post. The service is awesome, and there is so much you can make there. My creativity level sky-rocketed as I was browsing the site.
Drew working with the Dremel tool.

Drew working with the Dremel tool.

Once we had our pattern pieces arrive from Ponoko, we started assembling them. Our tolerances were a little tight, but nothing too major. A little light filing and everything went together nicely. For the small areas we used a jewelers file and in the larger areas we made a few passes with the Dremel tool. The material we purchased was the Acrylic Arctic Ice (Frosted 1-side) 4.5 mm. It is very nice, and sturdy!
Drew practicing drilling into wood.

Drew practicing drilling into wood.

The holes to mount the servos onto the leg base were a little too small for the size screws we had. I let Drew use the Dremel tool to drill these out a little larger. If you are working with your kids, let them practice bringing the drill down into a piece of wood first so they can get the feel of it.
Drilling into the Acrylic

Drilling into the Acrylic

After a few practice holes, I held the piece down (we didn’t have any clamps) so that he could drill out the holes. Up to this point, the entire process has only taken about a half hour. The knowledge will go on for a lifetime!
Rachel helping to test the servos.

Rachel helping to test the servos.

Once we had all the pieces ready and assembled we started working on the code. To control the servos, I decided to use the standard “sweep” sketch that is included with the Arduino IDE. I felt this was a good entry level piece of code that was easy to understand and be able to explain to Drew.

The first few attempts we tried did not work. This is where we discovered that different brands of servos have varying pulse rates. Our earlier robot used parallax servos, and we had no problems. These servos are from Hitech. After trial and error, we finally got them figured out. If you use the code from below, you may have to adjust the (pos) and delay variables. What is posted here is what eventually worked for the servos we are using.

Rachel mounting the servo connectors.

Rachel mounting the servo connectors.

The hook up is fairly easy. Servo motors have three wires: power, ground, and signal. The power wire is typically red, and should be connected to the 5V pin on the Arduino board. The ground wire is typically black or brown and should be connected to a ground pin on the Arduino board. The signal pin is typically yellow, orange or white and should be connected to pin 9 on the Arduino board. Our sketch uses pins 9 and 10. We used a 9.6V RC car battery, that goes to a 5V regulator on a small breadboard. This provides power to the Arduino and servos.

Arduino Bug Bot. Walk Test #1

Test #1 of the Arduino Simple Walker aka Bug Bot, we have movement but will need to put something on the legs so they grip and do not slide on the floor. We will also have to secure everything to the bug bot a little better to keep it from falling off. As you can see in the video, once it starts to move, the small pieces of double sided sticky tape did not hold and wires became unhooked. As you can see this is a learning process. I will post another update soon.

Arduino Sketch File
Photo of finished Arduino Simple Walker, Bug Bot

Ponoko.com 50% OFF your make fee: use coupon code VUFCRN at time of check out.
UPDATE: Ponoko.com just let me know that the coupon is a first come first serve. Its good for the first person who uses it.


Veja a matéria eo video que contem

http://arduinofun.com/blog/2009/05/09/arduino-simple-walker/

 

You need to a flashplayer enabled browser to view this YouTube video