Let's Make Robots!
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Hey guys! Here its me again with another "not so smart" project. As my second robot, I chose to build an obstacle avoider with an arduino duemilanove and the ultrasonic ranging sensor HC-SR04. Well, this is not a perfect model of obstacle avoider robot but I learned somethings building this robot... Things like organization of robots, appearence and stuff. It works in simple way: the robot goes foward and verify the distance using the ultrasonic sensor, if an obstacle approaches the robot stops and turns the servo to the right, verify the distance and then turns the servo to the left and verify the distance again. If the right distance is bigger than the left's, the robot turns for right and continue your way, the same happens for the left distance. I used an Tamiya Wheels and Tracks set to build the locomotion system, also I used a Tamiya Twin motor gearbox to power the track sets. I chopped the acrilic platform where the eletronics are installed by myself and I fix it with some screws and hot glue. The power source for motors is an pack of 3 AA alcaline batterys which I control using an Arduino Motor Shield v3 (based on L298 H-Bridge i.c), and the power source of arduino is divided with the power source of servo and sensor: I used an 9v alcaline battery and a L7805 voltage regulator, through input 9v/GND I powered the arduino board and through the output 5v/GND I powered the servo and the sensor. Well, I'm still working on that and I think the program code needs more adjustments to works fine. But I'm glad for now because I'm just a begginer and this is my most important robot build untill now.

 

[UPDATE - September 08/2012]

Added a new video (bottom video) of Botzilla working better. I've adjusted the code, now it has more movements and precision in measure the distance, also I added a heat dissipator in L7805 voltage regulator because it was heating too much, and fast!

And the surprise... I've signed up this robot in a National Robotic Fair here in Brazil. I hope the organization choose him to be showed in the event!

 

[UPDATE - June 28/2013]

 

Added 4 new sensors. Two of them are for detecting edges and avoid them (following some suggestions) and the other two are for detecting obstacles near the sides of the robot (it can follow a wall, for example, with this new sensors). The sensors are digital and it uses infrared retroreflection to locate the obstacles, a AmpOp TL081 is sending the signal to the arduino... The next is just simple if/else programming. You can see the upgrade runing in the bottom video.

 

I just forget one thing... I did presented Botzilla in that National Robotics fair that I've mentioned before. It is a succes! Well, maybe I'ill update this with a better description, but for now this is all I've got for you guys.

PS: if someone is interested in the sensors, I can give the circuit schematics or, maybe, write a tutorial teaching how to build them here on LMR.

 

 

 

[Last considerations}

 

I'm assuming that now the project is completed. Botzilla was accepted to be presented in an regional event of engineering students called "Semana da Engenharia" (something like Engineering Week, in a free translation). I learned so much thing with this project and take a lot of inspiration for my future designs. The next robot generations that I want to build will be far more organized and have a clean design, but the learning that I got with the old Botzilla will always remain with them. I thank you for reading this and I hope that you enjoy my simple project. More robots derivated of Botzilla will come (I'm already thinking in a lot! Including an aquatic one) and I wish you a good luck in your robotics projects.

 

 

 

See you guys!

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Stormbringer's picture

Nice, Calango!

I'm from Goiania, liked to see your bot :D

Calango's picture

Hi Stormbringer, its good to see brazilians here in LMR.
Thank you and see ya!

pulpy's picture

hey I am from INDIA,

i want to order the same kind of track Belts, let me know the WEBSITE through online where i can purchase

Calango's picture
Pulpy, I'm from Brazil and I get this set here but this tamiya set is cheap and you can find it in almost every site of robotics. Thank you and good luck in your work.
Calango's picture

Thank you TeleFox. This robot is working better at this moment, I'll update soon. hehe You gave me a nice suggestion. I actually have made an digital edge detector using infrared led as emissor and an infrared photodiode as receptor, the circuit sends the signal of edge/non-edge by an TL081 operational amplifier i.c. I'll try to implement the edge detection later. Thank you again and sorry if I've wrote some wrong things, my english is not very good hehehe.

TeleFox's picture

Looks nice Calango, I've used that Tamiya plate set stuff before and it's really convenient, while still being lightweight.

Maybe the next step is to add a infrared sensor or two at the front so you can detect the edge of the table?