The 1000N Custom Test Machine is based on the Phidgets technology. This page describes the different Phidgets components of this machine.
Phidgets
Phidgets are a range of modular sensors and actuators designed to simplify the interaction between computers and the physical world. Their operation is based on a plug-and-play concept, allowing users to easily connect sensors and actuators to their computer using Phidgets hardware.
Wireless VINT Hub
The main element of this test machine is the Phidgets wireless VINT HUB. It offers a convenient solution for utilizing Phidgets sensors and actuators in remote locations without a direct computer connection. It enables accessibility through your local network via the Phidget Network Server.
Each port on the hub is configurable to function in various modes, streamlining the interaction with VINT devices, analog sensors, or logic-level circuits. Furthermore, each port includes dedicated power and ground pins, offering direct access to the Hub’s 5V regulated power supply.
That way, the user only needs to connect to the Phidgets wireless VINT HUB by wi-fi or ethernet to drive the machine composed of several Phidgets actuators and sensors.
More documentation about the Wireless VINT Hub can be found here.
4A Stepper Phidget
The stepper motor used for 1000N Custom Test Machine is driven by the 4A Stepper Phidget.
There is also two limit switches in this machine. When hit, the 4A Stepper Phidget stops the motor.
In the python module Crappy the 4A Stepper driver corresponds to a Machine Block for the Actuator: Phidget4AStepper.
More documentation about this driver can be found here.
Wheatstone Bridge Phidget
The Wheatstone Bridge Phidget serves as a load cell interface, enhancing the signal received from a load cell and delivering a reliable, digital output. By applying calibration parameters (gain), it can accurately transform the raw load cell output into precise force measurements.
The load cell used for the 1000N Custom Test Machine an S-type load cell. It can measure with accuracy loads up to 100 kg which is about 1000 N.
A load cell utilizes the principle of strain gauges, which are thin conductive wires attached to its surface. When a force is applied, the material undergoes strain, causing a change in the electrical resistance of these strain gauges. This change in resistance is then precisely measured and converted into an electrical signal with here, a Wheatstone bridge, providing an accurate representation of the applied force.
Through calibration of the load cell, the relationship between the variation in the cell’s electrical output and the variation in the applied force has been calculated: gain = 3.265e+05 N/V.
More documentation about the load cell can be found here.
In the python module Crappy the Wheatstone bridge corresponds to an IOBlock for the InOut: PhidgetWheatstoneBridge.
More documentation about the sensor can be found here.