View source for PRX2300 User Guide

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<metadesc>Detect the presence of a small object passing through this sensor. Connects to a VINT Hub using the digital input channel.</metadesc>
[[Category:UserGuide]]
==Part 1: Setup==
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== Part 2: Using Your Phidget ==

===About===
[[Image:PRX2300_About.gif|link=|left]]






The PRX2300 shines a beam of infrared light between its prongs, and can detect when the beam is broken by a small object. This sensor's signal can be read using the Digital Input channel class when it is connected to a VINT hub.

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===Explore Your Phidget Channels Using The Control Panel===

Double click on the Digital Input channel class under the port your PRX2300 is connected to.

[[Image:PRX2300_Panel_Example.jpg|link=|850px|center]]

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== Part 4: Advanced Topics and Troubleshooting ==
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{{UGC-Entry|VoltageInput or DigitalInput?||
You can use the PRX2300 by plugging it into a VINT Hub port and opening that port in '''VoltageInput''' or '''DigitalInput''' mode. For applications that involve opaque objects large enough to block the whole beam at once, we recommend using '''DigitalInput''' mode. For small or translucent objects, using '''VoltageInput''' may be necessary since a partial beam break may not result in a voltage high enough to register a state change (e.g. 1.8V in the case of the HUB0000).}}
{{UGC-Entry|Calibrating the PRX2300||
The PRX2300 has a small trim potentiometer on board to adjust the voltage offset. 

[[Image:PRX2300_pot.jpg|link=]]

If you're using this Phidget in '''DigitalInput''' mode (are detecting large opaque objects that will strongly break the beam), rotate the potentiometer counter-clockwise toward the (+).  No further calibration is needed.

If you're using this Phidget in '''VoltageInput''' mode, we recommend adjusting the voltage offset until it sits at around 1.25V when the beam is not blocked. Next, you should write a short program that will log all of the voltage data to a text file or spreadsheet (and set the data interval to the minimum value in order to catch all of the data), so you can determine which voltage spikes indicate and object and which voltage spikes are just noise. 

For example, suppose you tested the sensor and observed 4 objects pass through, resulting in the following data:

[[Image:PRX2300_graph.jpg|link=]]

If we assume the first two peaks are actually one object that just happened to allow some of the beam to pass, and the fifth peak is a false positive, then we can assume the peaks indicated by the four yellow arrows are the data that correspond with the four objects. In order for our program to correctly identify these, we need to set a high trigger (indicated by the green line) well above the fifth peak, but below the sixth peak. Similarly, in order to prevent the first two peaks from counting as two separate events, we must set the low trigger below the dip in between them, but above the dip between the next two peaks.

Once you've done enough testing to determine where your high and low triggers should be set, you just need to add a bit of logic to your voltage change event. If the voltage is higher than your high trigger, you can set a global variable that indicates that an object has been sensed, and you should not reset that variable until the voltage has dropped back down below the low trigger. Here's and example of what the event handler might look like in Python if our high trigger is 3.75V and our low trigger is 2.7V:

<syntaxhighlight lang=python>

eventTriggered = 0

def onVoltageChange(self, voltage):
    if voltage > 3.75 and eventTriggered == 0
        eventTriggered = 1
        print("Object detected!")

    if voltage < 2.7 and eventTriggered == 1
        eventTriggered = 0

</syntaxhighlight>
}}

{{UGC-Entry|The digital input is stuck on "False" even when the beam is unbroken||
Try adjusting the sensitivity trim pot on the PRX2300. If it's turned all the way clockwise, you will get this behavior. If it's still stuck on "False" after adjusting the sensitivity, try cleaning the emitter and receiver on the inside of the prongs to clear away any debris that could be blocking the infrared beam.
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