Abstract:

This paper presents a simple method that can be used to interface simulations of digital systems with hardware connected to the computer that can extend student experience during laboratory works.
The system is composed of software and a hardware part. The software is designed to monitor the simulations on the computer screen and to provide user-like interaction with the simulation interface and exchange interaction data with the hardware part.
The hardware is used to interface the simulation running on the PC with external input and output devices. Input signals are converted into inputs for the simulation interface; outputs from the simulation interface are converted into output signals that control output devices. The system can work with various types of simulations and can be used in university labs to test digital control systems with low to moderate complexity.
The simulations can be issued by generic simulation software (ex. simulators of relay or logic diagrams) or can be the result of dedicated simulators of specific proprietary hardware like microcontrollers, smart relays or programmable logic controllers.
Simulations created with animation programs can also be interfaced with the external hardware. For example, a simulation of an elevator system can be interfaced with an external hardware that implements at a smaller scale the elevator and its user control panels.
The software part monitors pixels on the screen that change color during simulations by periodically reading the displayed colors at interest point positions and comparing them with the previous values. If the color has changed at any interest point, the corresponding output value in an output register is set to “1”. Otherwise the value is set to “0”. Status of the output register is sent to the hardware part activating hardware outputs corresponding to “1” values in the register.
Points of interest on the simulation interface are put in relation with hardware inputs. Status of the hardware inputs are read and recorded in an input register. Modification of the input register is checked periodically and any value modification in the input register results in a virtual mouse click at the corresponding associated interest point.
Using the two components (hardware and software), any simulation can be transformed into a digital system which student can make to interact with the real world improving the understanding gained during the laboratory work.
Full paper will present the implementation and operation of the proposed method.

Keywords:

Simulation in education, interfacing simulators with real world.