Raspberry pi Project: IoT Treat Dispenser for Pets

I have two cats, and having to give them treats about 3 times a day became quite a nuisance. They would look up at me with their cute faces and intense stares, then running to a box full of cat greenies, meowing and begging for them. I had decided that enough was enough. No more getting up just to give a cat a couple of treats. Now was the time for a treat dispensing machine, because as the saying goes: "Programmers exist to make complicated stuff to do simple things less."

COMPONENTS

Raspberry Pi 3

Raspberry Pi Camera Module
Stepper Motor with Planetary Gear
I2C LCD 16x2
Barrel Jack to Terminal
DRV8825 Stepper Motor Driver
Capacitor 100 µF
Arduino UNO & Genuino UNO
Jumper wires (generic)

Instruction

1. Creating a Design
First was the choice of how to control my newly thought machine. Bluetooth would have had too short of a range, at only 30 feet with no obstructions. With this information, I opted to use WiFi. But now, how do I use WiFi to control the machine? A Raspberry Pi 3 has builtin WiFi capabilities, letting me use Flask to host a webpage. Next was the topic of the enclosure and how to dispense treats. I decided upon a rotating wheel design, where treats would fall into little sections, be rotated around, and then the treats would drop down onto a ramp and travel to the front of the machine.

2. Making the Fusion 360 Model

I began by creating a base model for the treat receptacle. Treats fall into a mini-hopper where they are then taken into a rotating wheel.

Next I added the Raspberry Pi 3 to the Fusion design, along with the other electronics, including an LCD and Raspberry Pi camera module. I also made a hopper that could store additional treats.

The walls for the treat dispenser are supposed to be cut out of 1/4 inch plywood on a CNC router. There are 7 pieces to it, 4 walls, a floor, and a top and lid piece that can open and close to expose the treats. Lastly, I created a "fancy" handle to open the lid.

Here is a render of the final design:

3. Setting Up the Pi

DFRobot reached out to me and sent their Raspberry Pi 3 and Raspberry Pi Camera Module. So after I opened up the boxes I got right to work by setting up the SD card. First I went to the Raspberry Pi Downloads page and downloaded the most recent version of Raspbian. I then extracted the file and put it into a convenient directory. You can't just copy/paste a .img file to an SD card, you have to "burn it" onto the card. You can download a burning utility like Etcher.io to easily transfer the OS image. After the .img file was on my SD card I inserted it into the Raspberry Pi and gave it power. After about 50 seconds I unplugged the cord and removed the SD card. Next I put the SD card back into my PC and went to the "boot" directory. I opened up Notepad and saved it as a blank file named "ssh" with NO extension. There was also a file I added called "wpa_supplicant.conf" and put this text into it:

network={     ssid=<"SSID">     psk=<"PASSWD">}

Then I saved and ejected the card and put it back into the Raspberry Pi 3. This should now allow for the usage of SSH and connecting to WiFi.

4. Getting the Camera Ready
By default, the camera is disabled on the Pi, so you must open the terminal type:

 sudo raspi-config        

to bring up the menu. Go to "interfacing options" and then enable the camera. Now just select "Finish" and insert the ribbon cable of the camera module into the correct area of the Pi.

5. Installing Software
There are several different softwares that can stream video, such as VLC and motion, but I decided to use the mjpeg-streamer due to its low latency and easy installation. According to the instructions on the site, do a:

 git clone https://github.com/jacksonliam/mjpg-streamer.git

 sudo apt-get install cmake libjpeg8-dev

To install the needed libraries. Change your directory into the folder you downloaded and then type:

make

Followed by:

sudo make install

export LD_LIBRARY_PATH=.

  ./mjpg_streamer -o "output_http.so -w ./www" -i "input_raspicam.so"    

http://<The Pi's Local IP>:8080/stream.html

http://<The Pi's Local IP>:8080/stream.html