CED 4904 Joystick

The CED 4904 is a battery-operated device that generates X-Y analogue voltages intended for manual control of the position of a cursor on a screen. A downward push on the control knob causes a switch closure that can be used to signal an event to the recording equipment.

Finger-operated X-Y direction motion with 30 degrees of tilt in any direction.

Usage

Connect a pair of BNC cables from the X and Y output BNCs to two analogue inputs of the recording equipment, and assign these inputs to be X and Y position respectively. It’s important that the d.c. input resistance of these inputs is 1 MOhm or greater.

Use another BNC cable to connect the 4904 Event output to an input on the recording equipment that accepts switch closures, if this function is required. Note that the CED 4904 does not source any voltage from this BNC connector, so will not show the switch state if connected, for example, to an analogue input.

When the power slide switch is in the ON position, the CED 4904 can be woken from its standby state by a short push on the rectangular ON pushbutton. It will remain in this state with the LED flashing every few seconds for about 7 minutes, at which point the LED will begin to flash rapidly. The rapid flashing indicates that the CED 4904 is about to turn off its power automatically. Use the rectangular push button to cancel this state and revert to normal slow flashes. Use of the push button at other times re-starts the 7-minute timeout period.

Battery life

In the interest of prolonging battery life, switch off the CED 4904 using the slide switch between usages, rather than relying on the auto-off feature.

The internal electronics of the CED 4904 drain around 3mA from the battery when the position knob is within about 80% of its maximum range. Beyond this excursion, to achieve ±5V output from a 9V battery, the internal range extension mechanism is smoothly activated. However, doing this consumes a further 5mA of battery power for each axis that is in range-extension. The spring-loading of the control knob usually means that the range extension is not activated during rest periods, but in order to reduce battery consumption, the user should avoid objects resting against the CED 4904 that result in the control knob being forced to one side.

$450