Data Sheet

Sensor Documentation Modern Robotics, Inc.
Version 1.4.3 32
Commands:
The command register may be set to any of the values from the command table. Once a
command value is entered into the command register the value will be saved in the
EEPROM.
Active Measurement Mode
Command = 0x00
In active measurement mode, the sensor takes a reading by illuminating a
surface with a white LED and measuring the reflected light. Active mode is useful
in identifying the color of a surface.
Passive Measurement Mode
Command = 0x01
In passive measurement mode, the sensor takes a reading without the white LED
on. Therefore passive measurement mode is most useful in determining the
color of a light source like an LED.
Operating Frequency
Command = 0x35(50Hz) or 0x36(60Hz)
The operating frequency is provided to enable the sampling to coincide with the
normal flickering associated with artificial lighting. This helps to reduce signal
noise and other issues. The operating frequency can be set to 50Hz or 60Hz.
Black Level Calibration
Command = 0x42
Black level calibration will run 64 measurement cycles to obtain an average value
for each of the 3 color channels.
During black level calibration, the sensor should be placed such that no surface is
within 1.5m forward of the sensor elements. The calibration process last about
1.5 seconds and when calibration is complete, the LED will blink briefly and then
the command register will be reset to 0x00 or 0x01 depending on the mode save
in EEPROM.
Black level calibration must be completed before white balance calibration.
White Balance Calibration
Command = 0x43
White balance calibration will run 64 measurement cycles to obtain and average
value for each of the 3 color channels and are adjusted according to the black
level calibration values.
During white balance calibration, the sensor must be placed approximately 5cm
(2in) from a white target. The target must be very white and not allow light to
pass through the material. At least 3 sheets of high quality copy paper will make
a satisfactory white surface for calibration. The calibration process last about 1.5
seconds and when calibration is complete, the LED will blink briefly and then the
command register will be reset to 0x00 or 0x01 depending on the mode save in
EEPROM.