MT4 and MT6 Trackballs

Trackballs are ideal for applications that require the precise positioning of a cursor on a display screen. Daco trackballs are extremely robust and are designed to provide an exceptionally smooth, free and linear action.

We have designed our trackballs to deliver the highest performance under the most difficult conditions. In many trackballs the encoder shafts used to sense rotation are also used to support the ball. This design leaves the device vulnerable to damage because any shock applied to the ball is transmitted to the encoders.

The use of inflexible suspension points means that, if the trackball is mounted at an angle or is subjected to vibration, the contact between ball and encoder can be broken, thereby stopping meaningful electrical output. And as the ball can never rotate in the direction of both encoder shafts simultaneously, there is a bias in the ball’s rotation that prevents it from operating smoothly.

Daco trackballs feature separate support and encoder shafts, optimising function and usability.

Ball rotation is sensed by two high-quality optical encoders that, in our modular designs, contact the ball via a soft polyurethane foam roller chosen for its resistance to compression set, flame and corrosion. The foam’s flexibility allows it to “ride over” any small particulate contamination, which can cause jamming on other trackball encoders. This also ensures that contact between the ball and the encoders is maintained even if the trackball is mounted at an angle or is subjected to heavy vibration.

We have engineered the encoders specifically for demanding applications. They have very low friction and inertia, which means there is minimum effect on the “feel” of the trackball’s operation.

The ball itself is supported by six stainless steel ball bearings – within a polymer bearing – that are free to rotate in any direction. This means that there is never a bias in the direction of operation. Any excessive force applied to the ball is transmitted through the lower polymer bearing into the robust housing holding it, thereby avoiding damage to the encoders.

The result is a highly-reliable and cost-effective design.

 

Electrical

Excitation Voltage: 5 ± 0.5 VDC
Current: 150 mA + output current
Output voltage, per encoder TTL compatible true square wave on output A (Yellow) and B (Orange)
High: 2.7V min.
Low: 0.8V max.
Output current, per encoder 18 mA max sink; Fan out of 10 TTL
Insulation, per encoder >10M ohms at 500V
Direction sensing +X: XB leads XA by 90 ± 30°
+Y: YA leads YB by 90 ± 30°
Typical Resolution 1.5 inch ball: 150 pulses per ball revolution
2.0 inch ball: 200 pulses per ball revolution
2.5 inch ball: 250 pulses per ball revolution
3.0 inch ball: 300 pulses per ball revolution