Let's Make Robots!

Big Bertha - Obstacle avoidance

Navigate around with infrared sensor
Bertha.txt5.85 KB

Hi all! So, this is my second robot, not finished yet.

Like the first one, the structure is made with knex and the controller is an arduino uno. This time it uses an infrared sensor moved with a micro servo to check distances, and the 2 back wheels are powered wih separated DC motors. The 2 DC motors are controled via a module (bought all mounted) using a double H-bridge (L298), which allows changing direction and speed of the 2 motors separately.



Update 07 october:

Structure changed completely (was too heavy with all the batteries, wasnt strong enough).

Added pizeo buzzer when starts.


Current problem : when arduino is powered through a usb cable, it works, but when powered with batteries, it acts strangely : the wheels don't go in the right direction and it doesn't change speed or direction when obstacle are met. I really don't see what's the reason why it doens't act the same way when it's powered with usb or batteries.



Update 14 october : By switching batteries (so now, 6AA for arduino and 4AA for the motors), no more problem. A few interferences, easily deleted by adding capacitors in parallel with motors.

Changed also the algortihm, now the robot (almost) never gets stuck --> check videos.


Next project : add bumper sensors (like simply two switches), make the robot learn by himself how to use the datas coming from the infrared sensor to avoid obstacles, that is to say, avoid that the bumpers bump. I know it's gonna be difficult and maybe I won't succeed but I want to try.


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My Dad has this big fork lift tractor thingy that he named Bertha:P just saying. oh and nice robot!

Yes there was no real reason, but the shape of the robot inspired me the name Big Bertha ^^. oh and thanks!

Cool construction. Your battery problem makes no sense for me. It should be enogh if the batteries are full charged. Do you have thick enough wires from your battery to the motors?

Thanks! The batteries are quite new. I used them on a precedent project and there was no problem...

I'll rewire the thing to see if this is the problem. But I'll have time to do it only next weekend.

Your next project sounds a lot like my robot.

Yeah that's exactly what I want to do :)

Good luck!  I can't wait to see how you do it.  (or, if you want to know how I did it, I'll be happy to tell you)