Step 1: Collect information
Step 2: Cat Feeder Modeling
Step 3: Cat Feeder Structure Building
Step 4: Register IoT MQTT topic
Step 5: Write the MQTT Cat Feeder Program of the Future Board
Step 6: MQTT Debug
Step 7: Kittenbot WeChat mini program remote IoT control
Step 8: Test It Out

Team Kittenbot: Anny Xu, Christina Zhang, Riven, hogan96, Ccfive Wu

Published November 4, 2021 © MIT

IoT Pet Feeder to Feed Your Pets Remotely with Your Phone

We used an ESP32 Future board and 3D printing to build a cat feeder that can feed our cat when we are not home

IntermediateFull instructions provided5 hours2,358

Things used in this project

Hardware components

KittenBot Future Board

KittenBot Robotbit -robotics expansion board for micro:bit

Software apps and online services

Kittenbot MQTT

KittenBot Scratch-based editor Kittenblock

Story

We have two cats in the office. On weekends, some colleagues would go to the office to feed them. But what if they don't have time? So, in order to ensure our cats get fed every day, we made a cat feeder this time.

In addition to the things listed above, we also need:

1 × USB-C

1 × Android phone

1 × 2KG motor

1 × Glue gun or AB glue

1 × Utility knife

1 × Sealed storage box

1 × hungry cats or dogs or some other pets

Several LEGO bricks

Some pet food

Mind Maps of This Project

Overall mind map

Technical mind map

Step 1: Collect information

Generally, we should collect information before we start to make the project so that we can complete our project more efficiently and perfectly! Many people would buy a pet feeder to feed their pets, so we can find information about it easily.

The first station of information collecting: Amazon!

Almost all the cat feeders are in the form of bin + plate. Now we know what should our cat feeder look like.

But we are still not sure how the inside part of the cat feeder looks like. We can click to view the promotional pictures or videos to figure it out.

1 / 3

As can be seen from the above figures, the machine makes use of the gravity of the cat food. There is a rotating structure at the bottom of the bin to stir and push the cat food out.

Now we have a basic idea of the machine's structure.

The second station of information collecting: https://www.thingiverse.com/

thingiverse is a global 3D model sharing website, which shares a variety of interesting and fun models. You can first go and see if there is a cat feeder model, then we don't need to model but just print it directly (Sometimes we can be "lazy" ;)

Many people have shared their models on the website, you do can print them directly, but the 3D printer we made before may not be big enough for them. Also, the models they share all include their special items, such as bottles with a strange shape, which we definitely do not have. So we decided to make a 3D model by ourselves.

From the website, it seems that the easiest structure of the cat feeder is of the screw form, so we will model according to this form.

Step 2: Cat Feeder Modeling

There are many 3D modeling platforms, within which Tinkercad may be the easiest platform to master for students. It has an enjoyable interface and is very useful if used for simple modeling or teaching.

However, for more complex projects, Fusion 360 may be a better option.

Fusion360 is a 3D modeling platform launched by Autodesk. This software is very popular and is free for personal (non-commercial) and educational users, so it has a very broad mass base.

If you have never tried this type of platform before, you can find various tutorials on Youtube about Fusion 360 like this one here.

Okay! Let's get started. First, we draw our structural sketch, like this:

Then we model in the Fusion360 according to what we drew.

The attached 3D model file can be opened directly. One of the magical parts of Fusion 360 is that you can see the author's modeling process at every step, like a video player.

Step 3: Cat Feeder Structure Building

After exporting the model, we perform 3D printing. After one night of printing, we assemble the 3D printed parts, storage boxes, and Lego structural parts together.

Use a utility knife to dig a round hole at the bottom of the storage box (55.6mm in diameter)

Mix AB glue to glue the printed parts

Glue it

Assemble Future board, Robotbit, and 2KG servo together

Step 4: Register IoT MQTT topic

Log into the Kittenbot IoT server: iot.kittenbot.cn (It's in Chinese but don't worry! It's easy to use, just follow the instructions)
Register a topic, my topic name is CaatFeeder (You need to register another unique name)
It's not that hard, right?

1. address 2. add a topic 3. Topic name 4. create

Step 5: Write the MQTT Cat Feeder Program of the Future Board

Program Download：📎Cat Feeder Program.zip

1. Flowchart: understand the MQTT cat feeder program of the Future board

2. Write a graphical program with Kittenblock according to the flowchart

You need to modify two things:

Change your WIFI name and password
Change the topic name (replace my CatFeeder)

3. Program Download

Choose Firmware → Connect → program → switch to coding → download:

Step 6: MQTT Debug

The Kittenbot MQTT server also has a debugging function, which can send messages directly through the webpage (the webpage is a sub-device of MQTT)

If nothing goes wrong,

When you send 1 to the corresponding topic (CatFeeder here), the machine starts feeding!

Send

If you cannot get the same result, please check

Whether the Future board has connected to WIFI, if so, the IP address will be shown on screen;
Whether the 18650 battery of Robotbit is powered, and the switch has been turned on;
Whether the name of the program is the same as that of the MQTT server applied.

Step 7: Kittenbot WeChat mini program remote IoT control

Search "Microbit Controller" in Wechat

Choose the IoT function

Type in your topic name, and click "subscribe"

Type in 1 in the topic content, then click "send"

Step 8: Test It Out!

Check out the final effect:

Here we end this tutorial. If you have any questions please comment down below~

Cat feeder.py

#/bin/python
from future import *

import robotbit
import mqttsimple

from time import sleep

flag = 0

def off():
  global flag

  robot.motorStopAll()
  neopix.setColorAll((0,0,0))



def on():
  global flag

  neopix.setColorAll((0, 170, 0))
  buzzer.melody(BA_DING)
  for count in range(10):
    robot.motor(1,255)
    sleep(0.5)
    robot.motor(1,-255)
    sleep(0.5)
  for count in range(10):
    robot.motor(1,255)
    sleep(1)
    robot.motor(1,-255)
    sleep(0.5)
  neopix.setColorAll((0,0,0))


robot = robotbit.RobotBit()
screen.clear()
wifi.connect(str(""), "")
while not wifi.sta.isconnected():
  pass
mqtt = mqttsimple.MQTTClient("iot.kittenbot.cn", "ccFboard",port=1883)
mqtt.connect()
mqtt.subscribe("CatFeeder")
neopix=NeoPixel("P7",3)
neopix.setColorAll((0,0,0))
while True:
  mqtt.check_msg()
  sleep(0.1)
  flag = mqtt.mqttRead("CatFeeder")
  if bool(flag):
    if flag == (str(1)):
      on()
    else:
      off()

IoT Pet Feeder to Feed Your Pets Remotely with Your Phone