Crist Instrument Co., Inc.	111 West First Street
		Hagerstown, MD 21740
		Phone: 301-393-8615
		Fax: 301-393-8618
		Email

SECTION 7 - SEARCH COILS, SCREENS & OPTICAL SYSTEMS

MAGNETRACK 3000 EYE TRACKING SYSTEM

Front View of the Magnetrack Complete set-up of Magnetrack with the coil-frame (Oscilloscope not included)

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The Magnetrack 3000 Eye tracking system is a completely analog system. The complete system includes a search coil frame of the customers needed size, and a modular driver/receiver system. Because the unit is modular, the Magnetrack 3000 can be configured around your specific investigations. You can begin with the basic system and add other modules as your research needs change. Just refer to the table below and select the unit or units that best suits your needs.

The basic model for eye tracking includes two drivers; one for the vertical and one for the horizontal coil frame. It includes one or more receivers depending how many coil-sensors your experiment needs (eye coils, forehead coils etc). 3D eye tracking can be achieved by adding a third driver and coil frame. The system can be configured the way you want. The control module has 6 slots and can receive 6 different modules of any kind; present modules (like our drivers, receivers and reward modules), future modules or custom made modules!

There are two driver modules with 4 frequencies each, giving you an option of 8 frequencies to choose from. This permits up to four 2-coil systems to operate adjacent to one another without interference. The low frequency driver range is from 70-85 kHz. The High frequency is from 90-105 kHz.

Switching between different sizes of the field coil frames requires a simple replacement of the capacitor boards. Capacitor boards are available for different sizes of Crist field coils . For field coils made by other manufacturers we need the inductance of your field coil frames. We will send you a small replacement daughterboard that plugs into our driver board. With this simple procedure one can drive any coil size or make he/she wants from just one unit making it a real space saver!

Our receiver output can give you up to 24 Volts peak-to-peak and it operates 360° Vertically or Horizontally. This in theory gives you a sensitivity of 0.075 ° for a noise level of 10mV (SNR=68db) and for an angle range of 180 ° (min to max). If your experiment requires less of an angle range (as it probably will) e.g. an angle range of 90 ° , then the sensitivity will increase!

Features:

1. Monitors eye movement 360 ° horizontally and 360 ° vertically.
2. Modular design aids in upgrading and customizing it to any degree based on research need.
3. Ability to monitor 3D movement by adding another set of field coils.
4. ‘Sync’ switch restores synchronization, so it doesn’t matter how you place the coil frame.
5. Flexibility to increase the resolution of the output using the Advanced Settings.
6. Need not have a separate Reward-System as this unit may include our new reward-system controller that can be operated with a wireless from a remote location.
7. Theoretical accuracy of up to 0.075 °.

Customized modules for other than eye tracking or rewards are a phone call away.

• Our famous Reward unit has also been configured to fit into the Magnetrack 3000 unit. No need for a separate control unit for your rewards when space on your rack is limited. For additional information on the Digital Rackmount Reward Controller Unit (5-RLD-D1 & D1B) also refer to the paragraphs in Section 5 of our catalog.

7-MTS-Magnetrack 3000 Eye Tracking System

Ordering Matrix

Notes:

(Same function as 5-RLD-D1-B but in Magnetrack 3000 module)

MAGNETIC FIELD COILS (SEARCH COILS)

The Magnetic Field Coil has a non-conductive frame that supports the coil windings to produce a linear magnetic field at the center of a cube. It is driven by an electronic driver system, which when operating creates the linear magnetic field. Our field coils work best with the Magnetrack 3000; but, can be configured to work with other manufacturers control units. These coils come in a variety of frequencies and power levels.

Crist Instrument coil frames are available in a variety of sizes to fit various eye detector systems. The coils are available in 15-inch, 18-inch, 22-inch and 36-inch. Coils of other sizes can be produced upon request. If your organization owns a coil driver system produced by another manufacturer that does not provide the coil frame, we would be glad to produce it to their specifications in any size.

7-SSCP-15 Search Coil, 15-inch (38.10cm)

Designed to fit over most Standard size Chairs and to rest on side supports (wings). The inside opening diameter is 13 inches (33.02cm). The Coil diameter at the winding is 15 inches (38.1cm) and the outside diameter is 18 inches (45.72cm) on each side.

7-SSCP-18 Search Coil, 18-inch (45.72cm)

Designed to fit over a Large Chair or when your Standard Chair has options which would interfere with the 15 inch fitting over those options. As with the 15 inch, it rests on side supports (wings). The inside opening diameter is 17 inches (43.18cm). The Coil diameter at the winding is 18 inches (45.72cm) and the outside diameter is 22 ½ inches (57.15cm) on each side.

7-SSCP-22 Search Coil, 22-inch (55.88cm)

Special order. The inside opening diameter is 20.125 inches (51.12cm). The Coil diameter at the winding is 22 inches (55.88cm) and the outside diameter is 26.375 inches (66.99cm) on each side.

7-SSCW-36 Search Coil, 36-inch (91.44cm)

Special order. This is one of our full sized coils. To make it easier to center the chair within the coil a lifting device is recommended. See Section 8, Laboratory Structures. The inside opening diameter is 34.5 inches (87.63cm). The Coil diameter at the winding is 36 inches (91.44cm) and the outside diameter is 41.5 inches (105.41cm) on each side.

7-OIM-AF (0) Eye Mask

The Eye Mask is designed to hold different color filters and occluders. This mask fits over the eyes similar to a pair of glasses and can be mounted on the three-part head holder (6-FHC-S2) on the primate chair. It can also be adapted to mount on a variety of other fixtures.

TANGENT SCREENS

Tangent Screens are one of the components used in studying the central visual system and visual behavior modes. Our Tangent Screens create a minimal image distortion and provide remarkably good light transmission. This screen works well for both front and rear projection. It is the result of over two years of developmental work and has been used since before 1989.

The screen material used is Lumiplex, providing a smooth texture with minimal pattern. As tested with a light source of 32.4 cd/m2, it has been attenuated to 15.8 cd/m2 when measured by a Tektronics Luminance Probe. Image intensity, under those conditions, for rear projections is reduced no more than 51%. It has been reported to us by some investigators to be reduced by no more than 15%. When establishing and repetitively recording visual receptive fields, the screen can be written on with a wax crayon or a felt-tip pen.

7-QTS-L1 Moveable Tangent Screen

This Tangent Screen is mounted on a frame that hangs from the ceiling. It can be moved in a straight line for a selected distance from the subject in order to aid in radian calculation. If it is preferred, it can be swung upward and latched in place near the ceiling. This will allow for a Touch Screen Monitor or some other device to be positioned in its place without interference. This is also a good storage position in that it is less likely to be damaged when not in use. The top of the screen has a hinge mechanism and linear bearings that allow it to travel easily along the visual center line, while the hinge allows for the storage position.

We recommend that installation of this type of screen be executed by Crist Instrument Technical Staff or at the very least by highly skilled craftsmen. Detailed instructions can be provided as needed. Help is only a phone call away. Installation is not included in the price of the screen.

7-QTS-L2 Stationary Tangent Screen

This model is fixed in place from the floor to ceiling with a preset distance from the center.

7-QTS-L3 Tangent Screen on Platform