Specifications

‍USB

‍The USB port can operate in one of two modes: Keyboard or Standard:

In Keyboard mode (also known as HID mode), your computer “sees” Riponda as a keyboard, making it possible with any software. Key press and light sensor info can be sent to the computer in different preset formats, selected via DIP switches. 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. A Matlab sample is also available.

‍Several protocols (data formats) are supported and can be selected using switches. Supported baud rates are 115200, 57600, 19200, and 9600.

‍Timing

Time from button press to having a signal out (on m-pod and USB ports): less than 500μs.
Typical USB driver delay when controller is in Keyboard mode: up to 12 milliseconds.
USB driver delay depends on the used USB driver and software. When used with SuperLab 6 or our C++ and Python libraries, the delay is 2ms with 0ms jitter. Otherwise, it is 5 to 6 milliseconds.
Light sensor latency: less than 10 μs. This is the latency of the response pad only; see below for the light sensor’s response time.

‍To get around delays inherent in USB drivers, Riponda 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.

‍m-pod Connector

‍The response pad is compatible with Cedrus’ range of m-pod devices. This allows the controller to send event markers to a recording device of your choice, e.g. EEG or eye tracker. The following signals can be marked:

Onset of key presses
Onset of light sensor
Onset of voice key (using a microphone)
Event markers sent via USB

‍Firmware

‍XID, or eXperimental Interface Device, is a technology first used by Cedrus in 2001 on Lumina’s first generation controller and later adopted on all Cedrus hardware products. Riponda implements the more advanced XID 2.0 platform. The firmware is upgradeable.

‍Power Requirements

‍The response pad does not require an AC adapter. It is powered by USB.

‍Cedrus Light Sensor

‍The light sensor is available in two colors: black and white. Notches are molded in on three sides to allow for easy positioning on the screen. The controller can be configured so that detection of light can reset the built-in timer.

Response time (dark to light): 0.05 milliseconds
Release time (light to dark): 4 milliseconds
Spectral sensitivity: 360-970 nm (visible light)

‍The response and release times are dependent on the amount of light.

‍The light sensor is small, measuring only 8mm (W) by 20mm (L) including the wire’s strain relief.