Let's Make Robots!


Navigate around via ultrasound and infrared sensors
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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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Hey, I'm sorry for taking time. I've uploaded the code of a preview version of Botzilla. I couldn't find the last code version, it might be somwhere in my computer archives haha. But this version its not so diferent from the final version, you can check it and use it as base for your own code. One more thing: I've added some observations and functions structures in the code that are in portuguese (my language), if you understand some portuguese I guess you can read it without any problems, but if you don't than you can use some translator. I hope you can use it :D 

Thanks for the code man! I really appreciate!

Sorry for posting the same message two times. I am new…..


I'm working on a similar setup with an arduino, motorshield, HC-SR04, etc.  My question though is why did you use a separate voltage regulator?  Isn't the arduino rated 7-12V input voltage?  Is there another benefit to using an external voltage regulator that I'm not catching?

Hello kanejp63! I was having problems with the power source. It is dificult to buy LiPo battery or other good power source here where I live, so I have to use alkaline baterys and they wasn't working fine. The DC motors requires more current than the baterys can provide, so the servo, sensors and arduino (it was reseting) was not working. But there is no problem if you get an ideal power source. Thank you for asking. Good job and see you!
Sorry for reply two times, I wasn't clear in my previous reply. The external voltage regulator its to provide 5v to servo and sensor, using 9v I've powered the arduino. I just could connect the servo and sensor power sources in 5v output voltage of arduino but it wasn't work fine, so I did it this way. It isn't the better form, but works fine. If you get some nice power source, you will not have the same problem :D thank you again!