PRE2017 4 Groep2

From Control Systems Technology Group
Jump to navigation Jump to search


A semi-professional guitar player, called Joop, has suffered from a stroke. This caused the right part of is body to be numb for the most part. He cannot play the guitar anymore. This project is all about him and starting a journey to get him back on the stage.

Information about Joop

Joop is a guitarist, who had played in three bands. In the summer of 2017 he suffered from a stroke. This caused brain damage, which in turn led to loss of functionality of the right side of his body. He has some difficulty with talking. He can move his right just from his shoulder and he can still walk with a rather stiff leg. The functionality in his right hand is completely gone except for his index finger and thumb, which he can still pressure agaist one another. Joop does not experience any pain in the right side of his body, fortunately. In the six month following the incident, Joop went a lot forward with his health. After the six months the improvements stagnated.

The kind of music used to play were from bands like Pink Floyd, Led Zeppelin and Van Halen. He played this using a plectrum and a lot of feeling coming from his left arm in bending the notes. This is the music we strive for to bring back to the guitar for Joop.


The focus of this project is to make a start in the direction of making it possible for Joop to play the guitar again. This includes finding out what are the possible ways to create an interface for him, with which he could play again. These interfaces need to be natural for him and should fit within his style of playing.

The goal for this project is to make a clear overview of the movements Joop can make. Joop should be able to use these movements for a couple of hours at a time, comfortably. These movements should also be natural and contribute to bringing his previous style to life again. This means that Joop should be able to use these movements or combination of movements to play fast songs and solos from Van Halen, for example.


The process that is used for this project is mostly iterative. The first step is a literature review. For all possible ways for Joop to play the guitar, there need to be little tests. This contributes to a concept or more concepts for an interface. These are shown under the section tests. They will be carried out one after the other. Every test contributes to the knowledge about the movements that are possible to use for a new interface.

Literature Review

In this project a foot pedal has been made and a mechanism which replaces the strumming hand. The system on the guitar strums each string of the guitar while the player frets each string[1]. The signals from the foot pedal are send wirelessly to the unit on the guitar, which actuates the strings based on the signal. The strings are played by knobs that go up or down over the strings controlled by actuators. These knobs are attached to the actuators by a spring. These knobs wear out in a couple of hours. Currently, the actuators can only play the strings at one volume.

This is a paper that shares a mechanism on the neck of the guitar which replaces the fretting hand. This done by a mechanism that pushes down the strings when commanded to using a foot pedal[2].

This is a company that makes custom instruments voor people with physical disabilities. They do this by, for example, using conductive paint. That makes for a kind of piano like playing experience[3].

This company has made a universal stand. This stand is also suitable for a guitar[4].

“Experiment with “open tunings” on the guitar – a guitar in open tuning requires less complicated fingering of chords and can be played using a slide to bar all strings on a fret to produce the notes desired. The guitar can be played lying face up on one’s lap, with the right hand fingers picking strings, and the left hand using the slide bar to the required fret. This may sound complicated to a non guitar player, but a guitar teacher who is familiar with open tunings and playing blues style guitar will understand this method. It’s important to keep an open mind and have an adaptive approach to the training. Usually where there’s a will, there’s a way. Playing a guitar with a slide is used in many styles of music and it’s kind of a shortcut to playing sooner. For one-armed guitarists – tune the guitar in open “g”, place face up on lap, place steel or glass slide on left pinky to bar frets. Attempt to strum with remaining fingers – or if the other arm has any gross movement, with that arm.”[5]

Experiments with Joop

While the right side of Joop's body cannot be used for playing guitar, the rest of his body is completely fine. Therefore, other parts of Joop's body need to take over the functionality of his right hand. Some experiments need to be carried out to see what other movements are useful and natural for Joop.

Foot piano

The name of the experiment says it all. A keyboard to be played with a foot is being used to see how easy it is to get used to this kind of movement. A tube around the largest toe is used to play the individual notes.

Joop played like this for two times 15 minutes a day for a week long.


At the end of the week, the ability to play the piano with the foot is there but the speed is quite low.

Actual outcome

After the one week practice, Joop was able to some songs on the piano with his foot but he needed to go slow to be able to play the songs.


The side-wards movement in his foot is not fast enough. So, it will not be possible to have kind of keyboard, with a key for every string. Although the playing experience was very comfortable.

Foot pedal

In this experiment a MIDI foot pedal will be used to 'pick a string'. This is done by having a different note played at different angles of the pedal. This is needed to see if the up and down wards motion of the foot has the comfort of the previous experiment and the speed that is needed to play the guitar. It is set-up so that when a certain is held on the pedal, one keystroke on the keyboard can generate a note. (change in air will trigger the chosen string using a MIDI breath controller[6]). The goal is to see how reliably Joop can pick the angles of the pedal with his foot. For the pedal six different ranges are used to imitate the six strings on the guitar. Every range has the same size.

Products used

- Expression pedal[7]

- 6.3mm audio female jack to 3.5mm audio male jack adapter[8]

- 3.5mm female jack to usb adapter[9]

- USB microphone [10]


Joop is able to use this pedal for a couple of hours without any strain. Although it will be getting used to, a week is enough time somewhat reliably pick the right angle for the right note

Actual outcome