IoT Weight Logging Scale
SFUptownMaker Introduction
This tutorial will show you how to hack a bathroom scale to post weight data to a custom website that you create! The principles involved in this can easily be adapted to work with any kind of sensor data you choose: insolation, temperature, weather data, or anything else that you want to track over time and get a visualization.
It uses an ESP32 Thing to read load cell data from an HX711 Load Cell Amplifier and display that data on a Serial 7-Segment Display as well as posting it to a Python-based website that can be hosted locally or on the cloud.
Required Materials
Hardware
To follow this project, you would will need the following materials. You may not need everything though depending on what you have. Add it to your cart, read through the guide, and adjust the cart as necessary.
Software
I've chosen to use a remotely hosted Linux server on Linode to host my website, but if you so choose you can host it locally using a Raspberry Pi 3 or other flavor of Linux-based computer. You'll need to download and install the ESP32 support package--instructions are available on that page. The library for the HX711 amplifier can be found and installed through the Arduino Library Manager. I used the one titled "HX711_ADC" by Olav Kallhovd, so make sure you download the right one. I used Python 2.7, which should be the default if you follow my instructions. You'll also need to install Flask, matplotlib, and (maybe) tkinter. I'll go through the installation instructions on those later.
Tools
No special tools are required to follow this tutorial. You will need a soldering iron, solder, general soldering accessories, and a screwdriver to disassemble the scale.
Suggested Reading
Before undertaking this project, there are a few tutorials that you may want to review.