What is Human Machine Interface?

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  • Written By: Mary McMahon
  • Edited By: O. Wallace
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  • Last Modified Date: 08 October 2019
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A human machine interface (HMI) is an interface which permits interaction between a human being and a machine. Human machine interfaces vary widely, from control panels for nuclear power plants to the screen and input buttons on a cell phone. Designing such interfaces is a challenge, and requires a great deal of work to make the interface functional, accessible, pleasant to use, and logical. Some engineers specialize in developing human machine interfaces and changing the ways in which people interact with machines and systems.

Two components are needed in a human machine interface. The first is an input. A human user needs some way to tell the machine what to do, to make requests of the machine, or to adjust the machine. Examples of input devices include keyboards, toggles, switches, touch screens, joysticks, and mice. All of these devices can be utilized to send commands to a system or even an interlinked set of systems.

The interface also requires an output, which allows the machine to keep the human user updated on the progress of commands, or to execute commands in physical space. On a computer, for example, users have a screen which can display information. A robot, on the other hand, may move in response to commands and store data on a hard drive so that people can see how the robot responds, learns, and navigates the world. Outputs can also include things as simple as status lights which alert people when toggles or switches have been activated.


The technology behind the human machine interface is constantly improving. Researchers have developed interfaces which can be controlled with the mind, for example, seeing applications for this technology among stroke patients and other people with severely restricted modes of communication. Likewise, outputs have become much more sophisticated over time.

As many people have noted, a poorly designed human machine interface can be extremely frustrating. On one end of the scale, the interface may be buggy or nonfunctional, causing difficulty because it does not work as intended. On the other end of the scale, the interface works, but it is designed in such a way that it is confusing and challenging to operate because it is not intuitive for users. The art of designing intuitive interfaces requires a deep understanding of how humans interact with their environment and an awareness of the psychology of designing interfaces in a way which will be accessible to a broad spectrum of humans. What works for an engineer in a human machine interface, for example, might not be as easy for a member of the general public.


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Post 4

I am a marine electrical engineer. I am interested in the HMI uses for a power plant on a sea vessel.

Post 3

User interface designs are considered for ergonomic effectiveness. This means that they are valued based on how accessible and easy they are to use. We will probably see billions of people using virtual reality and video games in the near future due to the fact that they are becoming increasingly easy to use. All you have to do is move your body, instead of learning the buttons on a controller. The potential of video games for education and execution of complex tasks is immense.

Post 2

Today, we are getting closer and closer to bridging the layman and the machine, creating layers and layers of code which simplifies which each layer. Certain codes are becoming like human language, and human language will soon be translated by machines for global purposes.

Post 1

When the computer was first introduced in its current screen format and with a personal bent, it was dismissed by many. The savvy Bill Gates saw the potential of such a mechanism. Like the model-T before it, Bill wanted to be a leader in bringing this personal computer to everyone. Today, we benefit from this risk which he and others like him chose to take.

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