GRAD Engineering LLC
Color spot light meter ...
Hardware & Firmware by Ron, PCB by Viktor
The sensor is capable of measuring light output from a LCD display with white luminance levels in the range of 1,000 cd/m2 to 0.1cd/m2. The sensor also measures room light.
The sensor resolution is 0.03cd/m2.
Accuracy at 500cd/m2 is +/- 2%.
Repeatability is +/- 0.1%.
10 readings per second in low resolution mode. (0.3cd/m2.)
1 readings per second in high resolution mode. (0.03cd/m2.)
Does not need to be synchronized to vertical sync.
Factory calibrated to NIS standards.
Clamps to top of monitor. (or any edge)
6 foot USB cable
optional 6 foot Serial cable with optional wall power supply
Measurement arm response time is approximately 0.5 seconds.
The sensor shall comply with in specification for the following ranges, typical with office environments.
1. Operating temperature 16 to 30 degrees Celsius.
2. Operating humidity range is 20% to 80%, non-condensing.
Storage and transit environmental range:
1. Temperature: -20 to +60 degrees Celsius
2. Humidity: 20% to 80%, con-condensing.
USB 1.1/2.0 full speed (12Mb/s)
USB VID, PID, Serial Number and Product Description string
300 byte receive FIFO and 100 byte transmit FIFO, 16millisecond latency
Voltage: 4.5 to 5.5 volts
Current: 450mA max during arm movements. 25mA operating current. Less than 500uA stand by.
Input capacitance less than 10uF. Internally fused at 500mA
USB SOFTWARE DEVELOPMENT information
D2xx (USB Direct Drivers + DLL S/W Interface)
Windows 98, Windows 98 SE
Virtual COM Port (VCP) Drivers
Windows 98 and Windows 98 SE
Windows 2000 / ME / XP
MAC OS-8 and OS-9
Linux 2.40 and up
b. SERIAL (optional)
9600 baud, 8 data bits, no parity bits, 1 stop bit
Tri-state RS232; (for RS232 bus applications) Able to share the PC to Monitor serial port.
Serial port turns on 1mS before data is sent and off 1mS after the end of data.
two character FIFO, no hand shaking
8 pin mini-Din
-Pin 3TXD (data from PC)
-Pin 2: RXD (data to PC)
-Pins 5 Gnd
External power (serial only)
Power supply 6 to 10V at 5mA operating. 450mA during arm movement. 500uA stand by.
Center pin 6 to 10 volts
Outside pin is ground
Pentium PC or better
Windows 2000 or XP
128 MB application RAM, 10 MB free disk space.
The command set is based on one character commands.
Responses are in ASCI. Numbers are in ASCI not binary. Responses end in a carriage return
In serial (RS232) mode the sensor has a two command buffer. It is ok to send more than one command without waiting for the response. Once the buffer is full all additional commands will be lost!
In USB mode there is a very large buffer. It is possible to send hundreds of commands that will take the sensor two minutes to respond to. It is best to limit the number of commands.