Hardware testing with OpenHTF & Python
Nominal Connect unlocks reusable script libraries for hardware testing
OpenHTF (Open Hardware Testing Framework) gives engineers a wide-ranging, open-source Python toolkit for hardware test scripting. Nominal Connect layers on real-time visualization and robust automation. Together, they operationalize Python HITL (hardware-in-the-loop) test scripts with customizable UIs – equipping engineers with proven test sequences and minimal setup. Let’s break it down.
What is OpenHTF?
OpenHTF is Google's open-source Python library built specifically for hardware testing. First shared at the 2016 Google Test Automation Conference by Joe Ethier and John Hawley, OpenHTF was born out of Google's Glass project, where traditional HITL software test frameworks fell short.
Why it exists
The Google Glass team needed something different: lightweight, adaptable, and agnostic towards hardware platforms. The result is a Python library designed expressly for hardware and electrical engineers, contract manufacturers, and suppliers.
Core features
Python-first scripting: Integrates effortlessly with NumPy, pandas, and more.
Modular design: Organized clearly into Phases (steps), Measurements (data capture), Plugs (hardware interaction), and Output Callbacks (result processing).
Detailed logging: Easy debugging and complete traceability.
Runs anywhere: Works seamlessly across Windows, macOS, and Linux; compatible with diverse hardware environments.
Using the power of a thriving community
From startups to multinational companies, OpenHTF has grown into a global community staple. It continues evolving on GitHub, driven by contributions from hardware engineers worldwide.
Check out the original GTAC 2016 presentation.
What is Nominal Connect?
Nominal Connect is a real-time testing and automation platform built specifically for hardware-in-the-loop (HITL) scenarios. Engineered for high-stakes environments, Nominal Connect provides clear visibility into your hardware’s real-time performance, leveraging the safety and speed of Rust.
Standout features
Python-first SDK: Runs OpenHTF and any other Python scripts.
Real-time visualization: Sensor data visualized at kilohertz speeds.
Robust offline testing: Dependable, repeatable tests without internet.
Custom GUIs: Tailored interfaces to simplify hardware control.
Automated orchestration: Streamlined management of continuous testbeds.
Simulation replays: Game-engine graphics for reviewing mission scenarios and historical tests.
DAQ streaming: Real-time acquisition of high-frequency data from NI cDAQ, LabJack, and others.
Edge-to-server integration: Effortlessly sync data between local devices and cloud servers for comprehensive storage and analysis.
Nominal Connect is already in action at aerospace launch pads, defense flight lines, and nuclear energy sites. Connect ensures reliability under pressure, delivering precise control for even the most demanding hardware tests.
OpenHTF + Nominal Connect:
Powerful stack for HITL test
These tools are most powerful in combination, when Nominal Connect directly runs Python-based OpenHTF scripts. With minimal effort, test engineers leverage nearly a decade of community-driven test scripts, visualizing and automating proven test sequences through custom Connect HMIs.
Here’s a simple example – measuring resistor values:
This script plots voltage measurements, calculates a line of best fit, and determines resistance (here, 0.67 Ω). Operationalizing UIs for the OpenHTF library is just a Python script away with Nominal Connect.
The next generation of HITL testing, available today
OpenHTF’s extensive coverage combines perfectly with Nominal Connect’s powerful performance. From initial development through mission-critical deployment, this stack ensures engineers test reliably, visualize clearly, and iterate confidently.