Specifications of the Lumina 3G Controller
The USB port can operate in one of two modes: Keyboard or Standard:
In Keyboard mode (also known as HID mode), your computer “sees” the controller as a keyboard, making it possible for any program to handle the controller’s output. Key press and scanner triggers can be sent to computer in different preset formats, selected from the front panel. No driver installation is necessary.
In Standard mode, your computer “sees” a device that is connected as a serial communications port. It is supported by several programs like SuperLab, E-Prime, Presentation, Inquisit, and others; C++ and Python libraries are also available. Several protocols (data formats) are supported and can be selected from the front panel. Supported baud rates are 115200, 57600, 19200, and 9600.
Time from button press to having a signal out (on Accessory Connector and USB ports): less than 500μs.
Time from scanner trigger input to having a signal out: less than 10 μs.
Typical USB driver delay when controller is in Keyboard mode: up to 10 milliseconds.
Typical USB driver delay when controller is in USB Standard mode: 5 to 16 milliseconds.
Light sensor latency: less than 10 μs. This is the latency of the Lumina controller only; see below for the light sensor’s response time.
Accessory Connector II
5 parallel output lines (TTL) to indicate button presses on response pad 1
An OR’d output line that is active when any button is pressed on response pad 1
An OR’d output line that is active when any button is pressed on response pad 2
3 lines to indicate when light sensor detects light, timer is reset, or an fMRI trigger is received
8 general purpose TTL output lines that can be controlled from computer
8 general purpose TTL input lines
External input to reset built-in timer
RS-232 serial output
To get around delays inherent in USB drivers, the controller can send time-stamped information in both Keyboard and USB Serial modes. The timer can be reset via a light sensor or an external TTL signal. In USB Serial mode, the timer can also be reset via a command sent over USB.
The controller provides two methods for accepting triggers from fMRI scanners:
Fiber optic, suitable for Siemens scanners. Minimum pulse duration is 5μs.
When used in conjunction with other Cedrus products such as m-pod (and depending on their availability), the following signals are available on Accessory Connector II:
To make all these data signals available while still using a small connector, the data lines are multiplexed and require some electronics to demultiplex them. They are not readily useable. The timer reset line is not multiplexed.
Serial input/output signals are available on Accessory Connector II and are not multiplexed. An m-pod is needed to convert the signals to RS-232 levels, the standard that is used in computers’ serial ports. m-pod also provides a standard DB9 connector. Supported baud rates are 115200, 57600, 19200, and 9600.
For maximum safety, the electrical trigger input can be optically isolated, guaranteeing that no unwanted electricity flows between the controller and your MRI scanner. When optically isolated, the input needs nominal 5mA and a minimum of 1mA. The input has a 100 Ohm resistor to limit the current to about 30mA if the source is not current limited. When not optically isolated, the connector sources current from 5V through a 1k resistor so the driver needs to sink 5mA.
Electrical, suitable for GE and Phillips scanners. Minimum pulse duration is 5μs. This input accepts both TTL and differential voltage signals.
XID, or eXperimental Interface Device, is technology first used by Cedrus in 2001 on Lumina’s first generation controller and later adopted on all Cedrus hardware products. The current 3G Lumina controller’s firmware implements the XID 2.0 platform. The firmware is upgradeable.
The Lumina controller ships with a medically rated, UL-60601 certified AC adapter. It accepts 100-240VAC, 50-60Hz input, and produces regulated 9VDC, 2.0A max. CE certified. See Accessories page for more information.
The optional Copper Outpost allows the Lumina controller to recognize two Lumina response pad sets instead of just one, allowing for a maximum of eight buttons.
The Copper Outpost can sit on a desk or be wall mounted. Its power is provided by the controller; no separate AC adapter is needed.
Cedrus Light Sensor
The Cedrus Light Sensor allows the Lumina controller’s built-in timer to be reset without delay — useful when taking advantage of the controller’s time stamping feature. It is available in two colors: black and white. Notches are molded in on three sides to allow for easy positioning on the screen.
Response time (dark to light):
Release time (light to dark):
360-970 nm (visible light)
The response and release times are dependent on the amount of light.
The Cedrus light sensor is small, measuring a mere 8mm (W) by 20mm (L) including the wire’s strain relief (8 by 14mm without it).