A variable-interval timer

A variable-interval timer with an audible tone output was designed to pace participants in human-factors studies. The timer can be operated in a continuous (recycling) mode or in a time-out (“beat-the-clock”) mode. In the continuous mode, the audible tone is emitted at the end of the preset interval and a new timing cycle is begun. In the time-out mode, the research participant must depress a switch both to avoid the tone and to begin a new cycle. The time interval can be digitally programmed for intervals from 1 sec to 2 h and 45 min. The operation of the timer is described, and construction details are provided.     

Transistorized timer for sensory-behavioral research

A timer circuit is presented that can produce pulse durations ranging from 1 to 20,000 msec. The timer has high reliability, is inexpensive, and simple to construct.     

Miniature reaction timer with memory

A pocket-portable instrument is described for the self administration, in the field, of simple reaction time trials with variable warning foreperiod. The device will store 100 reaction times in milliseconds for later readout in the laboratory, in addition to displaying them to the S at the time of the trial.     

An accurate repeat cycle timer.

This timer was designed to provide a compact and quiet unit to control the presentation of visual stimuli by means of a slide projector, but it is not limited to this use. It is a solid state device, ready for use as soon as switched on, and is made largely from commercial logic units. The output is in the form of contact closures: the ON relay and the OFF relay give short pulse closures at the beginning of their respective cycles. With circuit values as shown in Fig. 1, times, from 0.5 to 10 sec in increments of 0.5 sec with an accuracy of ±1%, are selected by separate switches on the ON and the OFF cycles. Single interval solid state timers have been described by Saslow and Markowitz (1964) and by Tapp and Clark (1964).     

Apparatus noiseless electronic switch and timer

In psychoacoustic testing and experimentation the avoidance of extraneous stimuli is most important, but the elimination of such cues is often difficult. A circuit is described which enables sound stimuli to be switched on and off in a manner which produces no unwanted transient signals. The circuit may be adapted to function as a noiseless changeover switch.     

A token-actuated timer for line-voltage devices

A token-actuated timer that detects the insertion of a flat washer (“token”) is described. The unit provides a timed line-voltage output and counts the number of times the line-voltage device has been operated. Using behavioral token economies, this device has been used to control the television watching of children by monitoring television watching time, and by controlling the amount of time the television is on.     

Using a token-actuated timer to reduce television viewing

A child watching an excessive amount of T.V. was provided a behavioral program featuring a token-actuated timer. Earned tokens were used to activate the T.V. for thirty-minute periods. The token-exchange system effectively reduced T.V. viewing and the reductions were maintained at two follow-up points. The principal contribution of the study is the development and evaluation of an electronically controlled device that was used to check the accuracy of parent-reported data.     

An inexpensive digital millisecond timer and event counter

A simple circuit for a digital millisecond timer and event counter is described. The total cost of the unit including all components, a power supply, and an enclosure is less than $30. Daily use in simple reaction time experiments has demonstrated the reliability of the design.     

A simple special-purpose interval-duration timer for acoustic research

A special-purpose interval-duration timer is described. The device is designed to interface with commercially available psychophysical packages, to be used in time interval calibration. The extremely low cost of materials justifies the construction of this essentially single-purpose device.     

A delay timer for presenting auditory and visual probes

A circuit designed to present auditory or visual probes is described. The circuit allows the probes to be delayed by a specified amount of time, and the volume (for auditory probes) or intensity (for visual probes) may also be adjusted. The circuit may be triggered by any device capable of emitting an electronic pulse-such as a computer or a tachistoscope.