Introduction
The SparkFun OpenScale - IoT offers an easy-to-use wireless solution to measure weight and temperature. This version of the OpenScale works with multiple load cell types and lets users access the device wirelessly over Bluetooth®, BLE and WiFi (using TCP/IP) to configure calibration value, sample rate, time stamp and units of precision through the OpenScale - IoT's serial menu.
The OpenScale IoT is built around the ESP32 Pico Mini module that handles both firmware and communication (both wireless and wired) and transferring scale and temperature data to a serial terminal . It also handles communication with the HX711, a 24-bit ADC for weigh scales; and the TMP102, for recording the ambient temperature of your system.
The board also includes a 3-pin screw terminal connector for attaching an external temperature sensor where needed as well as a Qwiic connector for users who'd like to add other I2C devices to their OpenScale project.
In order to follow along with this guide you'll need the OpenScale - IoT, a USB-C cable and a load cell. For our example, we've selected a 5kg Straight Bar load cell. You can find this and all other load cells SparkFun offers in our Force/Flex category.
Topics Covered
This guide contains three main sections: Quickstart Guide, Hardware and Software.
The Quickstart Guide goes over how to connect a load cell to the OpenScale - IoT and configure it using a serial terminal and the Configuration Menu.
The Hardware section provides a detailed overview of the OpenScale - IoT as well as instructions on connecting a load cell and temperature sensor to the OpenScale.
The Software section covers how to connect the OpenScale - IoT to a computer or Bluetooth device to perform initial configuration and calibration. It also has information on performing extended calibration steps as well as how to update the firmware.
Resources and Support Documentation
You'll find the board design files (KiCad files & schematic), relevant documentation (datasheets, white papers, etc.) and other helpful links in the Resources. Lastly, the Support section includes a Troubleshooting page that includes any helpful tips specific to this board as well as information on how to receive technical support from SparkFun.