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LitterBuddy

Hardware Requirements & Assembly Guide

Everything you need to build your own LitterBuddy smart litter box scale

Estimated Cost: $35-45 USD for all components, depending on where you source them.

Table of Contents

Required Components

Microcontroller

ESP32 board - We recommend the ELEGOO ESP-32 Development Board as this is the board we used during development and testing.

Approximate cost: $5-8 per board

Load Cell & HX711 Amplifier

50kg load cell with HX711 amplifier module for weight measurements.

Approximate cost: $8-10

LED Strip or Indicator

Adafruit NeoPixel Diffused RGB LED bulb for status indication. Other RGB lights may work; however, this has not been tested and some features may not be supported.

Approximate cost: $10-12

Power Supply

USB-C charging cable and 5V power supply. A battery pack can also be used to power the ESP-32 board; however, testing for this configuration has not been completed as of now.

Approximate cost: $5-10

Enclosure Materials

Wood or 3D printed enclosure for the scale platform and base.

Approximate cost: $5-10

Miscellaneous

Jumper wires, tools, and other small components.

Approximate cost: $3-5

Shopping List

We've created an Amazon list with all the components you'll need. You can also source these components from your local electronics store or other online retailers.

Tools Needed

  • 1
    Soldering iron and solder (for connecting components)
  • 2
    Wire cutters and strippers
  • 3
    Electrical tape or heat-shrink tubing
  • 4
    Hot glue gun or strong adhesive
  • 5
    Computer with USB port for programming the microcontroller

Assembly Instructions

Step 1: Prepare the Load Cell

Mount the load cell to the base platform. Make sure it's securely attached and level.

Load Cell Mounting Diagram

Tip: The load cell should be positioned so that the weight is distributed evenly across it when the litter box is placed on top.

Step 2: Connect the HX711 Amplifier

Connect the load cell to the HX711 amplifier module following the wiring diagram below.

HX711 Wiring Diagram

Connections:
- Load Cell Red → HX711 E+
- Load Cell Black → HX711 E-
- Load Cell White → HX711 A-
- Load Cell Green → HX711 A+

Step 3: Connect the Microcontroller

Connect the HX711 amplifier to the ESP8266/ESP32 microcontroller.

Microcontroller Wiring Diagram

Connections:
- HX711 VCC → ESP8266 3.3V
- HX711 GND → ESP8266 GND
- HX711 DT → ESP8266 D5
- HX711 SCK → ESP8266 D6

Step 4: Connect the LED Indicator

Connect the LED strip or individual LEDs to the microcontroller for status indication.

LED Wiring Diagram

Connections:
- LED Strip VCC → ESP8266 5V (or external power if using a high-power strip)
- LED Strip GND → ESP8266 GND
- LED Strip Data → ESP8266 D2

Step 5: Assemble the Enclosure

Assemble the enclosure to protect the electronics and provide a stable platform for the litter box.

Enclosure Assembly Diagram

Note: Make sure the load cell is properly aligned and the top platform is level. The enclosure should be sturdy enough to support the weight of the litter box and your cat.

Software Setup

Step 1: Install Required Software

Download and install the Arduino IDE and required libraries.

  1. Download the Arduino IDE from arduino.cc
  2. Install the ESP8266 or ESP32 board package
  3. Install the HX711 library and WiFi libraries

Step 2: Download the LitterBuddy Firmware

Download our pre-configured firmware from GitHub.

The firmware includes all the necessary code to read weight data from the load cell, control the LED indicators, and connect to the LitterBuddy cloud service.

Step 3: Configure and Upload the Firmware

Open the firmware in Arduino IDE, configure your WiFi settings, and upload it to your microcontroller.

// Edit these lines with your WiFi credentials
const char* ssid = "YOUR_WIFI_SSID";
const char* password = "YOUR_WIFI_PASSWORD";

// Your LitterBuddy device ID (from your account)
const char* deviceId = "YOUR_DEVICE_ID";

After uploading, the device will automatically connect to your WiFi network and the LitterBuddy service.

Troubleshooting

Weight Readings Are Inaccurate

  • Make sure the load cell is properly calibrated
  • Check that the load cell is not touching the enclosure sides
  • Ensure the platform is level and stable
  • Try recalibrating using a known weight

Device Not Connecting to WiFi

  • Verify your WiFi credentials are correct
  • Ensure your WiFi network is 2.4GHz (not 5GHz)
  • Check that your router is working properly
  • Try moving the device closer to your router

LED Indicators Not Working

  • Check the wiring connections to the LEDs
  • Verify that the correct GPIO pins are defined in the code
  • Ensure the LED power requirements are met
  • Try testing the LEDs with a simple blink test program

Community Support

Join our community forum for additional support, to share your build, and to connect with other LitterBuddy users.

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