Phidget22 Python Wrapper

1.25.20260408 · active · verified Thu Apr 16

Phidget22 is the official Python library for working with Phidgets in Python applications. It provides lightweight bindings to the native phidget22 library. The current version is 1.25.20260408, and the library is actively maintained with frequent updates, often multiple times per year, bundling native libraries for major operating systems.

Common errors

```
ImportError: No module named 'Phidget22' (or similar for submodules like Phidget22.Devices)
```
cause The Phidget22 Python package is either not installed in the active Python environment, or the import statement refers to the old Phidget21 library (e.g., 'Phidgets' instead of 'Phidget22').

fix Ensure `phidget22` is installed in your environment (`pip install phidget22`). Verify your import statements use `from Phidget22...` and not `from Phidgets...`. If using a virtual environment, ensure it's activated.
```
PhidgetException: TIMED_OUT (or a similar message containing 'Timed Out')
```
cause The Phidget device could not be opened within the specified timeout. Common reasons include the device not being plugged in, incorrect addressing parameters (serial number, channel, hub port), the device being busy (opened by another program), or a power issue.

fix Verify the Phidget is physically connected, powered on (if needed), and not already in use by another application (e.g., the Phidget Control Panel). Double-check any `DeviceSerialNumber`, `Channel`, or `HubPort` parameters you've set, or increase the `openWaitForAttachment()` timeout.
```
PhidgetException: BUSY (or a similar message containing 'Resource Busy')
```
cause The Phidget device you are trying to open is already open by another process or application. This could be the Phidget Control Panel, another instance of your program, or a different application.

fix Close any other programs or instances that might be using the Phidget, including the Phidget Control Panel. If you suspect a background process, check your operating system's task/activity monitor.
```
PhidgetException: DEVICE_NOTATTACHED (or a similar message containing 'Device Not Attached')
```
cause The program is attempting to interact with a Phidget channel that is not currently attached or has become detached. This can occur if the device was unplugged, lost power, or the `openWaitForAttachment()` call failed or was not used, and the program tried to access the device before it was ready.

fix Ensure the device is firmly connected and powered. Use `openWaitForAttachment()` with a sufficient timeout before attempting to read from or write to the device. Implement `onAttachHandler` and `onDetachHandler` to manage the device's state.

Warnings

breaking Upgrading from Phidget21 to Phidget22 involves significant API changes. Object structures have been broken into more modular components, property and method names have changed (e.g., `open()` instead of `open()`), and outputs/settings are no longer persistent across channel opens/closes.
Fix: Review the 'Upgrading Code from Phidget21 to Phidget22' guide in the official Phidgets documentation and rewrite affected parts of your application, focusing on the new modular object model and event-driven programming. Ensure you are importing from `Phidget22` and not `Phidgets`.
gotcha HID USB Phidgets on macOS (legacy devices) require special driver installation or the Phidget Control Panel to function correctly, even with the Python library installed via pip. Newer USB and VINT Phidgets do not have this requirement.
Fix: Install the necessary macOS libraries or the Standalone Control Panel from the Phidgets website. Check your Phidget's product page specifications to determine its USB stack.
gotcha Phidgets require specific addressing parameters (e.g., `DeviceSerialNumber`, `Channel`, `IsHubPortDevice`) for unique identification. Incorrect or missing parameters are a common cause of devices not attaching or 'Timed Out' errors.
Fix: Double-check that the addressing parameters match your physical Phidget device and its connection. If unsure, try omitting parameters with `openWaitForAttachment()` to allow the library to find any available device of the specified class.
gotcha Many Phidgets, especially certain VINT devices or hubs, require external power to operate correctly. A lack of power can lead to 'Device Not Attached' or 'Timed Out' errors.
Fix: Ensure that your Phidgets and any connected VINT Hubs have the appropriate external power supply connected and functioning.
gotcha The Phidget Network Server (used for remote Phidgets) can be blocked by firewalls, preventing Python applications from connecting to remote devices or discovering them.
Fix: Add `NetworkServer.exe` (typically in `C:\Program Files\Phidgets\Phidget22\`) to your Windows Defender Firewall exceptions, or configure your firewall to allow connections for the Phidget Network Server.

Install

pip install phidget22 Install with pip

Imports

*
wrong:
```
from Phidgets.Phidget import *
```
correct:
```
from Phidget22.Phidget import *
```
Phidget22 uses 'Phidget22' as the top-level package, distinguishing it from the older Phidget21 library which used 'Phidgets'.
TemperatureSensor
```
from Phidget22.Devices.TemperatureSensor import TemperatureSensor
```
Device-specific classes are found under `Phidget22.Devices`. It's common to import specific device classes for clarity.

Quickstart

This quickstart initializes a `TemperatureSensor` object, registers event handlers for attachment, detachment, and temperature changes, and then waits for a sensor to be connected. It prints temperature readings to the console as they occur. The program includes basic error handling and a clean shutdown.

import time
from Phidget22.Phidget import *
from Phidget22.Devices.TemperatureSensor import *

def onAttachHandler(self):
    print("Attach Event: " + self.getDeviceName())

def onDetachHandler(self):
    print("Detach Event: " + self.getDeviceName())

def onTemperatureChangeHandler(self, temperature):
    print("Temperature: " + str(temperature) + " °C")

def main():
    try:
        # Create your Phidget channels
        temperatureSensor = TemperatureSensor()

        # Set event handlers
        temperatureSensor.setOnAttachHandler(onAttachHandler)
        temperatureSensor.setOnDetachHandler(onDetachHandler)
        temperatureSensor.setOnTemperatureChangeHandler(onTemperatureChangeHandler)

        # Open your Phidget and wait for attachment
        print("Waiting for Phidget TemperatureSensor to be attached...")
        temperatureSensor.openWaitForAttachment(5000)

        print("Press Ctrl+C to Exit\n")
        while(True):
            time.sleep(1)

    except PhidgetException as e:
        print("Phidget Exception: " + str(e.code) + " - " + e.details)
    except KeyboardInterrupt:
        pass
    finally:
        try:
            temperatureSensor.close()
        except PhidgetException as e:
            print("Error closing Phidget: " + str(e.code) + " - " + e.details)

if __name__ == '__main__':
    main()

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