uThing::iPH¶
uThing::iPH is a USB dongle that provides lab-grade, high-precision, galvanically isolated pH and ORP (redox) measurements.
It's designed for easy integration into custom applications, gateways, or for building continuous monitoring systems.
Key Features¶
- High-Precision Measurement: Lab-grade accuracy for both pH and ORP (redox) monitoring.
- Galvanic Isolation: Isolated data and power paths prevent ground loops and protect your host system.
- Automatic Temperature Compensation: Uses an onboard sensor or an external waterproof probe for accurate pH readings at any temperature.
- Very High-Impedance Input: Ensures compatibility with virtually any pH/ORP probe without introducing measurement errors.
- Core Processor: STMicroelectronics ARM Cortex-M4.
- Simple Connectivity: Plugs into any USB host (Linux, macOS, Windows, Android) and works as a standard Virtual COM Port (VCP) with no drivers needed.
- Flexible Output: Provides data in JSON (default), CSV, or a human-readable format.
Measured Data Points¶
The device outputs the following data:
- pH: Calibrated and temperature-compensated value (last and average).
- Raw Voltage: The direct voltage reading from the probe in millivolts (mV).
- Temperature: From both the onboard sensor and the external probe in degrees Celsius (°C).
Block Diagram¶
The figure below shows a block diagram of the dongle:
Isolated input
While measuring pH in industrial environments, it's important to avoid errors due to different ground potentials (ground loops), or to protect the systems from high voltages when an error occurs. The uThing::iPH™ was designed with this in mind, and provides isolated power and data paths for to the analog domain and ADC.
Very-high impedance analog frontend
pH and ORP probes can have high impedance values in some cases reaching resistances above 1 GΩ. Therefore, in order to avoid introducing substantial errors, the input impedance of the measuring system has to be much higher than the probe itself. The uThing::iPH™ analog frontend was carefully designed to have an input bias current as low as 20 fA!, or an equivalent input impedance well over the TeraOhm range, achieving insignificant offset error, even with the most demanding probes (i.e. ±0.2 mV for a 1 GΩ probe).
Next Steps¶
Ready to see it in action? The best way to start is with our Quickstart Guide.
If you want to dive deeper into the device's capabilities, check out these sections:
- Configuration: Learn how to customize settings like output format and reporting frequency.
- Outputs: Get detailed information on each data point.
- Calibration: Understand the calibration process for accurate readings.
- pH Measurement Theory: Learn more about the principles behind pH sensing.
- Specifications: View the full technical details.