Leo Lin

View project on GitHub

Squirrel chasing robot (object detection)

I wanted to create a robot to chase the squirrels and other animals in my yard away because they are eating the plants:( So the general idea is to have a outdoors wheeled vehicle that is autonomous, it drives around on its own and follow the squirrel by tracking it in the camera.

Engineer School Area of Interest Grade
Leo L Monta Vista High School Electrical Engineering Incoming Junior

Fifth Milestone

After quite a lot of testing, I found out thaat obsocle avoiding would be smoother with two ultrasonic sensors. With one sensor, theres just no way for the robot to know whether to turn left or right. Using two sensors allow for both movements to happen intelligently.

And the general logic is pretty simple. One sensor faces left and the other faces to the face at 45 degrees. If the sensor on the left side detect a object closer than a set distance, the robot turn to the right. If the right side sensor detects an object, it turns to the left instead.

The code:

I brought the robot out for the test, the improvement yielded some nice results:

I also added a robotic arm for the camera, as explained in the Milestone video:

Fourth Milestone

I saw places for improvement, especially in autonomous driving. I wanted the robot to be less passive in one single location, instead, it would be better if the robot can nativate mine or anybody’s yard by itself. I considered line following and mapping, but object avoiding is very user friendly and requires no extra “set ups” for anyone who would use this robot.

I first need to understand how a robot can avoid obsocles. Similar to humans, if we walk to close to a wall, we would turn left or right and continue with our walk. For my robot, it needs a way to detect that distance. This will require a ultra sonic sensor. It’s a cheap little sensor and the concept behind it is that it will send a sound wave, and calculate the time it takes for the wave to return to the sensor. When the sensor get its data, it needs to communicate with my raspberry pi: the brain of the robot. I really need a circuit diagram this time because there are some complications.

Circuit Diagram:

The code for the ultrasonic sensor involved its own library to send pulses, and use a timer to record the length of the pulse. At last there’s a quick math conversion for the time in microseconds to be translated into centimeters.

Here’s my milestone video for the demonstration:

Third Milestone

I downloaded opencv to take frames from videos in real life, and thus detecting squirrels in real time. Using the code I’ve written previously for detection and driving, I combined them into a autonomous driving system. The robot will turn to the right, and constantly updating its camera to look for squirrels, once it spots one, it will move forward to scare it away.

Here’s the loop part of the code:

Basically, I take in a frame from the openCV livestream, sends it to nanonets; if squirrel is detected, the squirrel drives forward. Else, the robot turns to the right. (Then it loops)

Third milestone video!

Second Milestone

Next step is to make a robot capable of driving around the outside terrian. To suit that outdoor requirement, I chose a tank chassis for my robot. The components for this step is: wires, breadboard, battery packs, motor driver, and motors. First step I made a circuit diagram to plan out the electrical components.

Basically, the raspiberry pi controls the motor driver, and the motor driver is then connected to the motors to power them. At last, I looked into the documentation for raspiberry pi to send signals using its ports, and wrote the code for the robot to run on keyboard.

Here’s a 3d CAD i made in tinkercad to help me understand the build:

Second milestone video:

First Milestone

My first milestone was setting up my raspberry pi and connecting the nessary camera component. I had to install Raspiberru pi imager on the SD card and plug it into the raspberry board, then it powered up. Next, because I didn’t have a spare monitor, I had to set up VNC to remotely view and control my raspberry. Now I can control the raspberry from a window on my personal computer.

Next, i want to test out object detection. So i went on nanonets, which is a AI training API website. They asked for 50 pictures of squirrels, and I learned that boxing(annotating) the squirrels in the pictures manually helps the model to be trained to identify squirrels. After the training is complete and tested for accuracy, I get a piece of python code that calls my unique nanonets model API. I can insert it anywhere in my python code and it will return me a json file stating where the squirrel is in the picture by coordinates. Nanonets has a tester itself, so I uploaded a squirrel picture I have not used before, and got a result with the squirrel annotated :)