First, we’ll make a python list of the candy we like and a list of the candy we don’t like. After we fire up the python program, you’re going to dump your unsorted candy into the machine. The individual candy bars will be sorted onto a conveyor belt. The conveyor belt dumps the piece of candy into the imaging basket.

Once they’re dumped into the imaging basket, the ultrasonic sensor is tripped and the BrickPi turns off the conveyor belt. In the imaging basket, the Raspberry Pi camera will take a picture of the candy bar and upload it to the Google Cloud Vision, asking for a brand label.

Google Cloud Vision will search the image and return its best guess for what the brand is of the object (candy) in the picture.

Finally we’ll compare the value returned by Google Cloud Vision to a list of candy we want to keep, and a list we want to give to our brother. The candy sorter will dump in one direction if it’s a keeper, and another if it’s a reject! As a final touch, the speaker will yell out loud whether it was Good Candy or Bad Candy, and what brand candy it found.

Coming soon: LDRAW Diagrams.

Wire Up the Raspberry Pi

To finish the project, you’ll need to connect a few things:

• The Conveyor Belt Motor goes into Motor Port B.

• The Imaging Basket Servo connects to Motor Port C.

• The Rake (the motor on top) connects to Motor Port D.

• The Raspberry Pi Power Supply connects to the Micro USB Port of the Raspberry Pi.

• The BrickPi Power Pack connects to the power port of the BrickPi.

Remember to connect the Camera! We’ll be using a Raspberry Pi Camera with the Raspberry Pi, here are some directions on setting up the camera.

These Raspberry Pi Camera set up directions assume you’re using Raspbian for Robots on your SD Card. You can buy an SD Card with Raspbian for Robots on it, or you can download it for free and install it using our directions here. If you’re not using Raspbian for Robots, you will need to take additional steps to enable and set up your camera; here are some directions on setting up the camera.

The example python program is located on our Github Repo here. You should also check out our Github Repo on using the Raspberry Pi Camera with Google Cloud Vision here.

Since we’re using Raspbian for Robots, there are only a few changes that need to be made to the software. All of them are specific to using Google Cloud Vision on the Raspberry Pi. We have a very thorough tutorial on how to get set up here. In short you’ll need to run the following in the command line

sudo pip install --upgrade pip 
sudo apt-get install libjpeg8-dev 
sudo pip install --upgrade google-api-python-client 
sudo pip install --upgrade Pillow 
sudo apt-get install python-picamera, espeak

Finally, you’ll need to upload your Google Application Credentials in JSON to the Raspberry Pi. Use an FTP program (such as FileZilla) or for Windows users Samba (see our tutorial here!) to move the JSON file over to your Raspberry Pi. Place the JSON file in the home directory (“/home/pi”).

Next, we’ll turn on Super User and make our credentials available. In the command line, type the command “su”:

su
You may need to run

sudo su 
and you may need to enter in your password. Next, we’ll make the JSON credentials available to Python. In the command line, run the following:

export GOOGLE_APPLICATION_CREDENTIALS=filename.json

Be sure to substitute your JSON filename in this command with the name of the file you have on your Raspberry Pi.

Finally, we’ll download the code. Again, this should go into the home directory:

cd /home/pi

sudo wget https://github.com/DexterInd/BrickPi_Python/raw/master/Project_Examples/candysorter/candy.py

Step 4: List your Gold (or Trash)

sudo nano candy.py

good_candy = ['Mars','Milky Way','Bounty'] 
bad_candy = ['Juicy Fruit','Doublemint', 'Snickers']

su
python candy.py