P13363Touch Sensitive

Piano KeysJustine Converse (ISE)

James Cover (CE)Alexander Eschbach (EE)

Jason Hang (ME)Ashley Trode (EE)

Introduction - Background• A typical MIDI (Musical Instrument Digital Interface) controller allows for the

flexibility of musical parameters beyond just playing notes with the use of a wheel or joystick that controls all keys at the same time.

• MIDI allows for easy communication and compatibility between digital instruments, computers and other related devices. It captures note events and music parameter adjustments and encodes them into a digital message.

• This message can then be interpreted and decoded into music. This tool is designed for the musician to play the keys of the instrument with one hand while controlling parameters with the other.

Project Objectives• The sensors will only be implemented into four of the piano keys, two white

and two black to demonstrate feasibility

• Sensors will have the capability to be mapped in two dimensions to be able to control two separate music parameters

• One dimension will be able to change a user selected parameter (i.e. volume, vibrato, etc.) over each individual key and the other dimension will change pitch bend over all keys Roland PCR 300 will be altered to incorporate this new sensors into the keys

• Microcontroller will be able to get input from these sensors and output a MIDI recognizable signal.

MicroController - Stellaris Launchpad

• Chosen because of speed, number of ports, and compatibility with 5V logic.

• The frequency of the Stellaris controller is high enough to process the necessary input within the expected delay, and can also output a MIDI message that complies with the MIDI specification.

PCBs

Sensor Main

Implementing Sensor into Keys• Needed to be able to incorporate the trackball and sensor PCB into

the key

• Current Roland PCR 300 key design made it difficult to build in needed components

• Created a new design made including trackball & PCB easier. New keys designed to look and function the same as existing ones and be compatible with existing Roland PCR 300.

• Both keys utilize a new notch function that allows the trackball and PCB to be easily inserted into the top of the key

• The new keys were prototyped with the use of rapid prototyping on a 3D printer

CAD Drawings of White & Black Keys

Programming

Programming

Testing

Software• 1-trackball testing

o Roll in x directiono Roll in y direction

• 2-trackball testingo Play 1 key with trackball, 1 withouto Play 2 keys with trackball

Testing

Hardware:Keys

o Prototyped key material was different than actual production key.o Not reasonable to compare the two for strength testing.o Tested whether it fit and functioned like a normal key when replaced in the

keyboard.o Tested whether the key had a similar feeling while being played as the

original key

PCBo Connect all the signalso Verify that outputs are working (up, down, left, right)o Signals did not output, changed the hall sensors and verified againo Signals still did not output correctly, repeated until no hall sensors were lefto Verified main board being able to communicate with sensor boards

Results

• Only able to implement 3 sensors instead of 4. Not all axis work on the 3 implemented sensors due to hall affect sensors being burned out.o Due to lack of budget to buy moreo Didn’t have access to right tools

• Able to implement trackball sensors successfully into 3 keys with the use of rapid prototyping

Bill of Materials

Budget

Demonstration

• Able to demonstrate 2 axis control with pitch and modulation on one key

Questions?