As you can see, this has a small reservoir, so a pet feeder for a normal cat or small dogs or a really fat hamster

Features

• easy assembly, only require 2 screws for the motor and maybe hot glue, hand twist some wires
• Inexpensive
• ultrasonic sensor to auto feed/scare your pets
• limit the feeds per day (time and amount)
• esphome so easy integrate to Home Assistant
• Remote feeding
• Pick the speed and total rotation time of the servo (can reduce the noise)
• Schedule time to dispose kibble (testing)

short comings

• some kibble will get stuck in there, require tilting and run the servo a few time empty it.
• small kibble might not work that well, it can get stuck under the blade of the auger, hence the back and forward motion

BOM

• ESP board (I used the ESP32)
• 608zz bearing
• SG90 micro servo motor
• HC-SR04 ultrasonic distance measuring sensor
• some tape
• 4 wires
• a usb cable
• a 5v 2A power brick

Instruction

• Electronic (note: It is recommended to split the power cable to feed power to the esp and servo separately, but I don't like cutting a perfectly good usb cable)

  1. cut the power and GND around the middle for the servo, solder a wire with the cut power wire together and another wire with the GND wire so you have 2 wires branch off.
  2. connect the 2 branch off wire to the power and GND of the ultrasonic.
  3. connect the initiate end of servo power and GND wire to the VIN and a GND pin of the ESP, the signal pin plug into GPIO13
  4. Plug the ultrasonic sensor's trigger pin to GPIO23 and echo pin to GPIO22
  5. flash the esphome firmware found here: https://github.com/feletoch/pet-feeder
• Full assembly
  1. take the hopper, loops some tape around the center pole until the bearing fit snagging without wobble
  2. push the auger on to the bearing
  3. mount the long I shape arm to the servo and push it into the center hole of servo plate, secure it with the 2 screws
  4. put the plate on to the above assembly, the arm need to fit in the hole of the auger
  5. Start from the bottom, there are groves that matches each layers, place the assembly above into the grove.
  6. it is recommended to hotglue the servo and ESP down
  7. route the usb cable from the back of the top piece plug into the ESP
  8. Push the ultrasonic sensor to the designated hole of the top piece and push the top piece down to complete the assembly

20260411: remove the config here and updated the config to disable motion feeding and add schedule feeding