Using an Apple II microcomputer for real-time control in a behavioral laboratory

This report describes the hardware and software developed to implement an Apple II (48 KB) as a real-time control device for operant experiments. The hardware has a straightforward design, so that it is readily understandable and can be built by individuals with only minimal experience in the use of integrated circuits and other electronic components. The software routines listed below represent an approach to controlling and handling the data generated by an operant experiment. Using these routines, we are able to record each response and experimental event, the time of the occurrence, and the conditions at that time.     

An experimental psychology laboratory system for the Apple II microcomputer

A system for on-line control of experiments is described that uses the Apple II microcomputer and requires no knowledge of programming. This system, APT, is used to construct test files, randomize stimulus order, and conduct experiments. Construction of an experiment is very easy through use of an interactive program. APT provides powerful options for controlling stimulus duration, feedback, and response type. Programs are available to conduct either a sequence of tests without any experimenter present or a single experiment. Over 200 subjects, ranging from 18 to 86 years of age, have completed a battery of cognitive and abilities tests using the system.     

Writing high-quality statistical software for Apple II microcomputers

The purpose of this paper is to describe some principles and techniques that programmers should consider when trying to improve or create a statistical package. Four computational issues are discussed: accuracy, speed, computing probabilities, and error trapping. A single-array data structure is proposed for use within the program. Several other input-output issues are covered, including menus, command languages, questions, data input and editing, CRT and printer formatting, and graphics.     

A microcomputer interface for control of real-time experiments in cognitive psychology

A microcomputer system for real-time control of experiments in cognitive psychology is described. The microcomputer serves as an interface that allows a remote timesharing computer to control the timed display of textual material on CRTs and collect response times accurate to 1 msec. It can control two CRT subject stations presenting the same or different experiments and control other devices such as slide projectors and tape recorders. It is argued that such special-purpose microcomputer interfaces provide a real-time laboratory with significantly less effort than does the more traditional laboratory minicomputer.     

Some simple Apple II software for the collection and analysis of observational data

Two general-purpose software packages for collecting and analyzing observational data from a variety of settings are discussed. One package is designed for coding mutually exclusive behavioral states using the Apple’s keyboard as an input device. The other is designed to monitor temporally overlapping behaviors, and it makes use of the Apple II’s built-in game-control button inputs to indicate up to three behavioral states that may occur simultaneously.     

A microcomputer interface for applications requiring large numbers of subjects

While most small microcomputers are powerful enough to control intricate experiments, a major limitation of many is their limited I/O capability. An interface for the KIM-1 or similar small microcomputer is described that provides for up to 128 or more inputs. The basic components of the interface are a series of shift registers through which the incoming data are manipulated and read by the microcomputer. Provisions are also made to latch the incoming data, allowing detection of very high rates of or even simultaneous data input. The interface is modular in design and can be expanded by increments of eight inputs. Use of the system to monitor a large number of running wheels is discussed.     

A simple infrared photocell device and its interface to an Apple computer

This paper describes a simple infrared photocell circuit that is inexpensive and easy to construct. The light source and detector are housed inexpensively and are focused so the light and detector may be separated over significant distances. The circuit may be used in a variety of conditions, including total darkness and bright fluorescent lighting, without having to readjust or recalibrate the circuitry. Output from the circuit may be used to drive other transistors or electromechanical relays. With minimal additional circuitry and hardware the signal may be interfaced with an Apple computer.     

Graphics software and hardware for RT-11 systems

A general-purpose graphics package is described that allows the user to generate figures with a supraset of the basic CalComp plotting subroutines. The software runs under RT-11 on an LSI-11 with 28K words of memory. The graphics subroutine library is approximately 200 blocks long. The plotting tasks are passed over an RS 232 line to a simple extension of an inexpensive and commercially available graphics controller. The controller implements these tasks as plotting instructions to a color television, a vector display, and a digital plotter. The graphics subroutines are written in FORTRAN and are invoked by the user as subroutine calls from a FORTRAN program. The graphics controller is a modified Motorola “Micro Chroma 68 Kit.” The board is based on the 6808 microprocessor and 6847 video controller. It provides eight graphic modes from 64 by 32 eight-color graphics to 128 by 192 four-color graphics to 256 by 192 two-color graphics. The present software and hardware implements the graphics subroutines as 256 by 192 two-color graphics, as 512 by 512 vector graphics, and as stepping instructions for a digital plotter.     

A method for analyzing the motion of an object on a VTR screen with an Apple II computer

To detect position on a video tape recorder (VTR) monitor screen, two different types of apparatus were developed. One was a light pen, and the other was an instrument similar to an X-Y tracker. These were designed to work with the Apple II computer. Their circuit diagrams are presented.     

A microcomputer interface for decoding telemetry data and displaying them numerically and graphically in real time

A microcomputer (IBM-PC) interface for decoding ultrasonic telemetry pulse-modulated signals from either unisensor or multisensor (time-multiplexed) transmitters is described. Pulse intervals, recorded by the interface, and corresponding independently measured parameter levels (i.e., swimming directions, speeds, depths, water temperature, and ambient irradiance levels) are entered into a calibration file. The IBM-PC uses this file to convert the signal’s pulse intervals to sensor states and displays these in real time. States of up to eight multiplexed sensors can be displayed concurrently in either numerical or graphical format (as histograms) with low resolution (16 axis divisions) or, for a particular sensor, with high resolution (70 axis divisions). The circuit components mount on the IBM Prototype Card (with foil for interfacing logic) allowing easy installation in the IBM-PC’s expansion slot. The 35K of controlling software is written in Pascal with four subroutines in assembly language.     

A large-scale expandable I/O port interface for the TRS-80 microcomputer

Described is a large-scale expandable input/output port interface for the Tandy Corporation TRS-80 microcomputer.     

Limitations of high-level microcomputer languages in software designed for psychological experimentation

The execution times of microcomputer high-level-language commands can be long enough to be of concern in experiments in which precise timing is a consideration. The problems in developing standard BASIC timing routines are addressed. A technique for using the Model III TRS-80 real-time clock to calibrate BASIC timinig routines is described, and representative execution times of selected commands are reported. It is concluded that high-level languages are too slow and that execution times are too variable for critical timing in experiments. On the other hand, machine language programs can provide the needed precision and control.     

A split-screen electronic messaging system for Apple II computers

A method is described for configuring an Apple II+ or Apple IIe computer to create a multiuser, multiwindowed, electronic messaging system for use in computer-mediated communication research.