In real time, a brain signal is translated into output commands that accomplish the desire of the user. The most common example of use of such technology is the direct control of a computer cursor by a person or animal using a BCI based on electrophysiological signals.
Emg interface.

What is EMG? It is a technique for evaluating and recording the electrical activity produced by skeletal muscles. It is performed with an instrument called an electromyograph to produce a record called an electromyogram. It detects the electric potential generated by muscle cells when these cells are electrically or neurologically activated. The signals can analyze the biomechanics of human movement.

In Computer Science, EMG is also used as a middleware in gesture recognition toward allowing the input of physical action to a computer as a form of human-computer interaction Source Wikipedia.org.

History of all this.

In 2016 a startup called Emteq Labs launched a virtual reality headset embedded with EMG sensors for measuring facial expression. In September 2019 Facebook (Meta) bought a start up called CTRL-labs that was working on EMG. CTRL-Labs which was co-founded by Internet Explorer creator and neuroscientist Thomas Reardon and Patrick Kaifosh the other co-founder also a neuroscientist who got his PhD in 2016. CTRL-Labs had some patents such as the Myo armband, a gesture and motion control device. This armband measured EEG (electromyography) to translate muscle activity in to gesture-related software inputs. This armband was developed by North, formerly know as Thalmic Labs. The CRTL-Labs wristband can help develop ways to interact with machines without needing a mouse and keyboard or touchscreens. This has the potential to change the was we connect, says Andrew Box Bosworth head of AR and VR at Meta. North now makes a stylish pair of AR glasses known as Foclas. Facebook earlier paid 2 billion for Oculus VR in 2014. How will you control the computing. By the time you have glasses you may want something private. A discreet way to communicate with the device is a critical and a needed reality.