The first generation Smart Light Probe, CCLight, developed at Concord Consortium is designed to be powered directly from a Macintosh serial port. This version uses 0-5V RS-485 communication and is not compatible with standard RS-232 serial interfaces which use positive and negative signal levels.
The CCLight was developed by Concord's NSF-funded Science Learning in Context Project (SLiC). The CCLight is one of a class of small instuments combining sensors and interfaces we call SmartProbes. Checkout the SmartProbe home page for more information.
The CCLight is calibrated when it is manufactured and can be recalibrated in the field later by the user if a suitable reference luxmeter is available.
The CCLight probe has both a Low and High range which is set with a swicth located on the case.
The low range is 0-5000 Lux with a sensitivity of 1.4 Lux per unit of ADC resolution. In the Low range the green led flashes once per second. The high range is 0-125000 Lux with a sensitivity of 40 Lux per unit of ADC resolution. In the High range the green led flashes twice per second. Bright overhead sunlight typically will produce an illumination level of about 100000 Lux.
The light sensor used is a Hamamatsu S1087 photodiode. This photodiode has a built-in near-IR blocking filter which shifts the response to mainly visible light with a range of 320 to 730 nm and a peak response at 560 nm. This is much better for measuring illumination than standard Si photodiodes whose peak response is in the near-IR at 960 nm.
When the probe is connected to an active serial port it will turn on and transmit data in the standard Vernier Serial Box format at 2400 bps, and 53.9 data samples per second. This means that the standard Vernier Data Logger program can be used to collect and display data from the probe. CCLight has only one Port a however the calibrated data from the probe is reported in Port 1 and uncalibrated data is reported in Port 2.
With the appropriate program the CCLight probe will leave Data mode and enter Command mode where recalibration is done. This capability is not built into Data Logger. An end user program for recalibration is not available yet.
To use any CCLight probe with DataLogger you will need a copy of the Data Logger experiment and calibration file. You can download a self-extracting-archive here:
Data Logger Calibration and Experiment Files for CCLight probes on the Mac
The experiment and calibration files are named as follows
CCSmartLight-high
CCSmartLight-high.CLB
CCSmartLight-low
CCSmartLight-low.CLB
You can automatically start Data Logger and load the calibration file by double-clicking
the correct experiment file for the gain switch setting.
If you have technical questions about the CC Smart Light Probe you can write to me, Stephen Bannasch at stephen@concord.org.