LUX1000 User Guide: Difference between revisions
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<metadesc>The Light Phidget measures the ambient light level from 188 μlux to 220 klux and connects to a port on your VINT Hub.</metadesc> | <metadesc>The Light Phidget measures the ambient light level from 188 μlux to 220 klux and connects to a port on your VINT Hub.</metadesc> | ||
[[Category:UserGuide]] | [[Category:UserGuide]] | ||
== | ==Part 1: Setup== | ||
{{ | {{PT1 Deck Sequence}} | ||
== Part 2: Using Your Phidget == | |||
===About=== | |||
The LUX1000 measures brightness (illuminance) from 188 microlux (starlight on a moonless night) to 220,000 lux (direct sunlight). | |||
[[Image:LUX1000-about.jpg|850px|link=]] | |||
==Using the | ===Explore Your Phidget Channels Using the Control Panel=== | ||
You can use your Control Panel to explore your Phidget's channels. | |||
'''1.''' Open your Control Panel, and you will find the '''Light Phidget''' channel: | |||
[[Image: | [[Image:LUX1000_Panel.jpg|link=|center]] | ||
'''2.''' Double click on the channel to open an example program. This channel belongs to the '''Light Sensor''' channel class: | |||
{{UGC-Start}} | |||
{{UGC-Entry|Light Phidget: |Measures the illuminance in the area the LUX1000 is facing | |||
| | |||
In your Control Panel, double click on "Light Phidget": | |||
[[Image:LUX1000-LightSensor.jpg|center|link=]]}} | |||
{{UGC-End}} | |||
{{UG-Part3}} | |||
== Part 4: Advanced Topics and Troubleshooting == | |||
{{ | {{UGC-Start}} | ||
{{UGC-Addressing}} | |||
{{UGC-DataInterval}} | |||
{{UGC-Graphing}} | |||
{{UGC-Firmware}} | |||
{{UGC-Entry|Dynamic Gain and Sampling| | |||
| | |||
[[Image:LUX1000_response.jpg|link=|375px|thumb|The response of the photodiodes depending on the wavelength of the incoming light.]] | |||
The LUX1000 can measure the intensity of light in the range of 188µlx to 220klx. The device achieves this wide range due to its ability to dynamically change the gain value on its measurements, in addition to changing the amount of integration time taken per measurement. Changing the gain coarsely affects the range, while changing the integration time finely affects the range. | |||
Because of these dynamic ranges, you may see momentary saturation when trying to measure large changes in light intensity in short periods of time (for example, a strobe light). Once the light level stabilizes, the sensor will settle back into optimal range settings.}} | |||
{{UGC-Entry|Spectral Response| | |||
| | |||
The light sensor on the LUX1000 is designed to sense light in a way that emulates the response of the human eye. However, digital light sensors work very differently than our eyes do. Using the photoelectric effect, the photodiodes in the sensor will generate current when struck by incoming photons. The problem is that the range of wavelengths that these photodiodes respond to vary depending on what materials they are made of, and none of them have the same response as the human eye. | |||
The solution, offered by the chip used in the LUX1000, is to take readings from two different photodiodes. One photodiode detects only IR light (light invisible to the human eye), and one photodiode detects both visible and IR light. The device weights the measurements with coefficients based on calibration testing. Then takes the difference between the IR component from the combined IR and visible light. The result is a workable approximation of brightness, as seen by a human eye.}} | |||
{{UGC-End}} | |||
Latest revision as of 21:17, 17 January 2022
Part 1: Setup
Part 2: Using Your Phidget
About
The LUX1000 measures brightness (illuminance) from 188 microlux (starlight on a moonless night) to 220,000 lux (direct sunlight).
Explore Your Phidget Channels Using the Control Panel
You can use your Control Panel to explore your Phidget's channels.
1. Open your Control Panel, and you will find the Light Phidget channel:
2. Double click on the channel to open an example program. This channel belongs to the Light Sensor channel class:
In your Control Panel, double click on "Light Phidget":
Part 3: Create your Program
Part 4: Advanced Topics and Troubleshooting
Before you open a Phidget channel in your program, you can set these properties to specify which channel to open. You can find this information through the Control Panel.
1. Open the Control Panel and double-click on the red map pin icon:
2. The Addressing Information window will open. Here you will find all the information you need to address your Phidget in your program.
See the Phidget22 API for your language to determine exact syntax for each property.
The Change Trigger is the minimum change in the sensor data needed to trigger a new data event.
The Data Interval is the time (in ms) between data events sent out from your Phidget.
The Data Rate is the reciprocal of Data Interval (measured in Hz), and setting it will set the reciprocal value for Data Interval and vice-versa.
You can modify one or both of these values to achieve different data outputs. You can learn more about these properties here.
Note: Graphing and logging is currently only supported in the Windows version of the Phidget Control Panel.
In the Phidget Control Panel, open the channel for your device and click on the 
icon next to the data type that you want to plot. This will open up a new window:
If you need more complex functionality such as logging multiple sensors to the same sheet or performing calculations on the data, you'll need to write your own program. Generally this will involve addressing the correct channel, opening it, and then creating an Event Handler and adding graphing/logging code to it.
The quickest way to get started is to download some sample code for your desired programming language and then search google for logging or plotting in that language (e.g. "how to log to csv in python") and add the code to the existing change handler.
Filtering
You can perform filtering on the raw data in order to reduce noise in your graph. For more information, see the Control Panel Graphing page.
Graph Type
You can perform a transform on the incoming data to get different graph types that may provide insights into your sensor data. For more information on how to use these graph types, see the Control Panel Graphing page.
Firmware Upgrade
MacOS users can upgrade device firmware by double-clicking the device row in the Phidget Control Panel.
Linux users can upgrade via the phidget22admin tool (see included readme for instructions).
Windows users can upgrade the firmware for this device using the Phidget Control Panel as shown below.
Firmware Downgrade
Firmware upgrades include important bug fixes and performance improvements, but there are some situations where you may want to revert to an old version of the firmware (for instance, when an application you're using is compiled using an older version of phidget22 that doesn't recognize the new firmware).
MacOS and Linux users can downgrade using the phidget22admin tool in the terminal (see included readme for instructions).
Windows users can downgrade directly from the Phidget Control Panel if they have driver version 1.9.20220112 or newer:
Firmware Version Numbering Schema
Phidgets device firmware is represented by a 3-digit number. For firmware patch notes, see the device history section on the Specifications tab on your device's product page.
- If the digit in the 'ones' spot changes, it means there have been bug fixes or optimizations. Sometimes these changes can drastically improve the performance of the device, so you should still upgrade whenever possible. These upgrades are backwards compatible, meaning you can still use this Phidget on a computer that has Phidget22 drivers from before this firmware upgrade was released.
- If the digit in the 'tens' spot changes, it means some features were added (e.g. new API commands or events). These upgrades are also backwards compatible, in the sense that computers running old Phidget22 drivers will still be able to use the device, but they will not be able to use any of the new features this version added.
- If the digit in the 'hundreds' spot changes, it means a major change has occurred (e.g. a complete rewrite of the firmware or moving to a new architecture). These changes are not backwards compatible, so if you try to use the upgraded board on a computer with old Phidget22 drivers, it will show up as unsupported in the Control Panel and any applications build using the old libraries won't recognize it either. Sometimes, when a Phidget has a new hardware revision (e.g. 1018_2 -> 1018_3), the firmware version's hundreds digit will change because entirely new firmware was needed (usually because a change in the processor). In this case, older hardware revisions won't be able to be upgraded to the higher version number and instead continue to get bug fixes within the same major revision.
The LUX1000 can measure the intensity of light in the range of 188µlx to 220klx. The device achieves this wide range due to its ability to dynamically change the gain value on its measurements, in addition to changing the amount of integration time taken per measurement. Changing the gain coarsely affects the range, while changing the integration time finely affects the range.
Because of these dynamic ranges, you may see momentary saturation when trying to measure large changes in light intensity in short periods of time (for example, a strobe light). Once the light level stabilizes, the sensor will settle back into optimal range settings.
The light sensor on the LUX1000 is designed to sense light in a way that emulates the response of the human eye. However, digital light sensors work very differently than our eyes do. Using the photoelectric effect, the photodiodes in the sensor will generate current when struck by incoming photons. The problem is that the range of wavelengths that these photodiodes respond to vary depending on what materials they are made of, and none of them have the same response as the human eye.
The solution, offered by the chip used in the LUX1000, is to take readings from two different photodiodes. One photodiode detects only IR light (light invisible to the human eye), and one photodiode detects both visible and IR light. The device weights the measurements with coefficients based on calibration testing. Then takes the difference between the IR component from the combined IR and visible light. The result is a workable approximation of brightness, as seen by a human eye.
