Let's Make Robots!

Chariot Security Bot

Line Follower, Ultrasound collision avoidance, Streams Video


Ok first a little something about the name :)

Thought about some fancy name but after that profile picture it reminded me of a Roman Chariot so it got baptized that same moment :)

This is still in its early days, but it is supposed to become a security (line follower) robot, that goes through predefined path, and stops at some specific points. It has a USB camera plugged to the Raspberry Pi that streams to a local site.

The robot will be autonomous but it can be accessed through the internet and controlled via SSH where Python will send commands via Serial Port to the Arduino, manly to control the Pan Tilt Servos of the camera. At any given moment the Robot can be accessed and stopped so you can Pan and Tilt at any point of the track.

It is supposed to be a security drone that cycles trough the house streaming video. Later I will try to add microphone to detect sound...

I tried to do everything with the (50Ah) USB batterie but the 5V it outputs don't seem to be enough to power the DC motors. :(:(:( The initial goal was that but it seems impossible... I'll give it a try later.

As you can see in the video the robot describes a circle when it was supposed to go forward... :) I'll have to tune the speed of one of the wheels...

There is still a lot of code to write... Line following code, Tilt Pan, Ultrasound object detection, Raspberry PI to Arduino via Serial to command the robot... but I'll keep you posted real soon :)


Hardware used:Raspberry Pi, Arduino UNO,Magician Robot Platform with two DC Motors, 2 Servos, USB Camera, PAN/TILT brackets, USB HUB (the little blue robot), USB battery (5V - 50000mAh), HC-SR04 sensor, 1Wifi Dongle, LD293D Chip, 4xAA case, 1 medium breadboard, 1 mini breadborad and lots of jump wires...

IR pair (Sender and Reciever)

USB HUB connected to the Raspberry Pi, for powering Wifi Dongle, USB Camera and Arduino.

JerZ circuit for IR sensors used in the line follower. Added one more IR pair for the diferential calculation of the path.

Final look... Sorry for the wire mess :) but basicaly there is a mini breadborad on top of the Arduino and they are both on top of the batteries holder.

On the rear section there is a USB batterie for powering the Raspberry Pi on top. There is also a breadborad with the LD293D chip for controlling the motors and the adafruit Pi Cobbler, that for the moment isn't used.

Finaly on top of this piramid :) commanding it all the "Driver" Mr Robot USB HUB :):):)


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Looking forward to seeing this guy develop.

I don't think you'll have too much success with using the same power supply for motors and electronics. I've fond the Raspberry Pi to be very sensitive to noise on the 5 v line, and electric motors are NOISY!. 

I've got separate batteries for motors/servos and electronics, and it works much better.


Very cool, I was waiting for your dog to snatch it up!

Very cool, I was waiting for your dog to snatch it up!

This one hasn't been easy...

On the topic of the "one battery" solution I had to abandon that hope... unfortunately the robot didn't moved... had to place the 4xAA batteries.

Then came, has a surprise to me, the hardest part... getting it to follow a line :)

First I joined the sensors closer together but one of the kept giving me higher readings then the center and left sensors... then I had to take the sensor circuit apart and rebuild it with only two sensors... which simplified the calculations a lot... and then success

The hole thing is so heavy and it drained the rest of the batteries before I could do the video. I'll try to post a video asap.

Added video of line following progress.

Rearranged the sensors and took out the ultrasound sensor for now.

Don't know if its the weight of the bot or the code but sometimes it stalls on the curves... still trying to figure it out... :) 

Hi Diogo Branco!

Great robot and it moves quite fast! I think it behaves well even it needs some improvements, but looks like you are on the right way. It is funny how the dog look at the robot :-) Well done and keep going!