Bringin’ Saxy Back

Designers: Angela Cho, Jenna Freedman, Minyoung Ryoo

Client Coordinators: Linda Cates, PT

Supervising Professor: Kevin Caves

Abstract

Our client was a saxophone player who had a stroke leaving him with limited use of his right hand. We built a device that allows our client to play the soprano saxophone again without the use of the right hand via buttons that can be easily reached by the left hand and foot pedals. These buttons actuate solenoids that press down the right handed keys. We also built a stand that supports the entire weight of the device, while still allowing our client to adjust the instrument to his preferred height and playing angle. The stand was designed to allow our client to set-up and disassemble it independently, and our client demonstrated that he could perform this task. The stand supports the entire weight of the saxophone and allows for adjustments in height and angle. As for the performance of the device, all but one solenoid closed its corresponding key fully.Saxy Fig 2

Introduction and Background

The client is an accomplished saxophone musician who had a stroke four years ago. He has right side hemiparesis, which is, weakness on right side of the body caused by a stroke in the left side of the brain.1 This has left him with reduced movement in his right upper extremity (arm), which limits his ability to hold the saxophone in the correct playing position. The active movement he does have in his right arm is somewhat affected by spasticity, which presents as inability to open his right hand. The inability to open his right hand prevents him from playing most notes on the saxophone.

Multiple companies have built one-handed saxophones, such as Flute Lab3 and Russel Winds2. These products are extremely expensive. Aside from price, there are other constraints for our particular device to be both useful and practical. For example, the device must be storable. The client must also be able to assemble it independently. Finally, the device needs to be able to be played with the same speed that he was used to prior to the stroke.

Project Goals

The goal of the project is to develop a way for the client to play the full range of notes on the soprano saxophone with one hand. The solution will allow the client to play the saxophone with the fluidity and tempo that he wants. It will also allow the client to play for extended periods of time. Additionally, it will produce similar sound quality and pitch to that of a normal saxophone. Finally, the device will be something that can be independently set up and broken down.

Design and Development

Overall our modifications implement a new key system by actuating solenoids when a button is pressed to close the right-handed keys. The solenoids require a lot of power, but the use of a saver circuit significantly reduces the amount of power drawn, which in turn prevents the solenoids from heating up and makes using them a feasible option. Platforms attached to the support structure of the existing rods on the saxophone provide a surface for the placement of the buttons, the solenoids, and the circuit boards. A stand supports the entire weight of the device, while allowing the client to adjust the height and angle of the instrument to his preferred playing position. The device meets all the needs for our client to be able to play the saxophone again.

Fingering/Switches

The first step in developing our saxophone was to create a new fingering concept that allowed all the notes to be played without using the right hand. We developed a key map that could play almost the full range of the saxophone using only the left hand and two foot pedals. Our key map takes advantage of a few things: when any of the main right handed keys are pressed down, all of the left handed keys are pressed down; and when any of the right hand side keys are pressed down (labeled E/F, C), only the left hand palm keys are being pressed (not shown in diagram, but they do not require the use of any fingers). This modified key system allows the full range of the soprano saxophone to be played.

Solenoids/Circuits

The next step in development was to find a way to implement our key system. To do this we used solenoids to press down the keys when a button is pressed. We found a solenoid that both extended long enough and with enough force to press down any key, but it drew a lot of power and heated up quickly. To solve the heating problem, we implemented a saver circuit that would reduce current to the solenoid after the initial activation and reduce the power being consumed by it without reducing its ability. Using this circuit, the solenoid only heated up a few degrees after 30 minutes of continuous activation.

Saxy Fig 1

Figure 1: Components of Project

Platforms

Next we needed a way to place the buttons and solenoids in the proper position for our design to work. To solve this problem, we designed platforms that sit above the face of the saxophone. The platforms at the top of the saxophone hold the buttons within reach of the left hand (see Figure 1), while the platforms at the bottom hold the solenoids in the proper position over the right handed keys.

Stand

The final part of our design is a stand to support the saxophone. We want our client to be able to play the sax for long periods of time without hurting himself, but remaining comfortable instead, therefore we repurposed a music stand to support the saxophone (see Figure 1). The stand is adjustable in height and angle, which allows our client to play while either standing or sitting with any horn angle he wants. A metal casing is attached to the sax that slides into place via an adaptor at the top of the stand. This allows the client to easily attach and remove the sax from the stand, while also holding it steady when he plays. A box that houses the circuits is positioned at the base of the stand, and a DB-25 cable connects it to the buttons and solenoids on the saxophone.

Evaluation

In order to evaluate the effectiveness and quality of our device, we first tested our device with the client to assess the functionality. All but one of our solenoids functioned perfectly. The second right hand key was not able to be completely closed which caused the notes below it to be effected. When this second solenoid was pushed down manually, all of the notes were able to be played. To test the functionality of the stand our client assembled and disassembled it during our final client meeting, and he was able to adjust every component independently within ten minutes. The pitch of the saxophone was not affected by our device because the device only closes the valves and does not modify the instrument body. Our client said the pitch of the instrument was good, and he was pleased with the quickness with which he could play.

We tested the amount of force our stand could support by attaching a pull spring scale to the top of instrument stand and pulled it to 20 lbs. The stand showed no signs of stress. Our design specification was to support 15 lbs. To evaluate our client’s satisfaction with the device, we gave him a survey. The survey and the results can be seen in Appendix C.3: Satisfaction Measures.

Discussion

We developed a way for the client to play the full range of notes on the soprano saxophone with one hand. The use of solenoids allows the client to play the saxophone with the fluidity and tempo that he wants. The saxophone stand allows the client to play for extended periods of time. Additionally, the sound quality and pitch is the same as a normal saxophone because there weren’t any modifications made to the saxophone body. Finally, our client can set it up and break it down independently. Overall, the client was satisfied with the device.

References

  1. “Muscle Weakness After Stroke: Hemiparesis.” National Stroke Association. Web. 3 Sept. 2015.
  2. “Russell Winds – Band Instrument Repair, Modification.” N.p., n.d. Web. 27 Oct. 2015.
  3. “Saxophones for One-handed Playing – Flutelab.” Flutelab. N.p., n.d. Web. 16 Sept. 2015.

 

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