Detailed Design Review Project P13363 Members: Justine Converse (IE) James Cover (CE) Alexander Eschbach (EE) Jason Hang (ME) Ashley Trode (EE) Guide: Gerald Garavuso

Our Focus Mount sensor on 2 keys (1 white and 1 black key) Microcontroller will be able to get input from sensor and output a MIDI recognizable signal Sensors will 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 at the same time MIDI mapping will be the limitation to which parameters can be mapped Will use blackberry trackball for sensor

Engineering Specs/Requirements

System/Flowchart

System Diagram

What we decided last time Conduct further research and testing for two concepts... *Blackberry trackball/trackpad *Capacitive touch sensor

Capacitive Touch Testing (Initial) Simple RC circuit built with square wave input Touched leads of the capacitor Discovered that touching both leads has a more noticeable effect

Capacitive Touch Testing (Initial) One capacitor testing Rise time changes if a touch exists Left (no touch), Right (touch)

Capacitive Touch Testing (Sensor) Touchpad breakout board is from sparkfun Twelve electrode capacitive touch inputs per chip Microcontroller is needed to interpret the signal Microcontroller can tell when touchpads are contacted and when they are released The time touched could be used for sensitivity

Schematics - Capacitive Touch Circuit

Trackball Testing (Sensor) Trackball breakout board is from sparkfun 4 directions and a push button can be detected and outputted as a digital signal using four hall effect sensors and a push button The frequency of the digital signal is controlled by the speed of the trackball The position can be found by counting how many digital highs there are in a certain amount of time

Schematics -Trackball Circuit

Risk Assessment

Decision Based on Testing & Risks Move forward with Trackball Sensor o Easier to program  Repeatable results  Less data to manipulate

Schematics - Main Circuit Board Will consist of Microcontroller (still need to pick) power regulator inputs of trackball sensors MIDI circuit

Pseudocode (Interface Test Program) Initialize Microcontroller o Board Setup (Pin IN/OUT) o Interrupt Setup (Enable, Edge trigger) Wait for interrupt from trackball o Turn on LED o Delay o Turn off LED o Clear Interrupt

Pseudocode (System) Initialize Microcontroller o Board Setup o Interrupt Setup o System Setup  Buttons to change parameters  Sensitivity  Musical parameter per axis Wait for interrupt from trackball o Start timer o Count number of rotations in time period o Determine magnitude + speed Modify incoming MIDI signal

System Diagram

Timing Diagram

Pseudocode - MIDI Send 'Note On' Message o Key press Send 'Aftertouch' Message o Sensor data Send 'Note Off' Message o Release key

MIDI - Background MIDI - Musical Instrument Digital Interface An electronic musical instrument industry standard protocol set in 1983 Allows for easy communication and compatibility between digital musical instruments, computers, and other related devices Captures note events and music parameters adjustments and encodes them in a digital message This digital message can then be interpreted and decoded into music

MIDI - Types of Messages Channel Messages - used for controlling one or more of the 16 MIDI channels or for controlling musical notes using a specific MIDI channel System Exclusive Messages - longer MIDI messages that are used for a variety of purposes System Common Messages - Some standardized features that are used for controlling the playback of songs in MIDI format System Real-Time Messages- Used for timing and clock signals

MIDI - Channel Message Digital Signal

MIDI - Issues Individual control of certain parameters is impossible within the MIDI specification Creating a message that complies with the MIDI specification that other devices will understand

MIDI - Resolution Additional software is required for full control of all parameters Find contacts that know more about the MIDI specification or know where to find related resources o Music shops o RIT library o Manufacturers o Organization that controls/owns standard

Test Plan (Software) Play 1 key without sensor, get output Play 1 key with sensor, get output o Fast and short o Fast and long o Slow and short o Slow and long o Sensitivity o Multidirectional Play two keys, get output o One with sensor, one without o Both with sensor

Test Plan (Hardware) Unaltered keys o Normal Play  Have a pianist play the keyboard normally  Measure the forces applied to the keys o Maximum Play  Play the keys aggressively  Measure the forces applied on the keys Altered keys o Normal Play  Apply the force measured from playing normally o Maximum Play  Apply the force measured from playing aggressively

High Level Plan Overall system plan for the location of the components o Sensor o Wires o Microcontroller circuit board Microcontroller circuit location

Placement of Sensor on Key Discussed where pianist place their fingers when playing. Realized that there is no set location, usually all over the keys. Determined where NOT to place the sensors. Constrained to structure of the white and black key. Black key has a very limited amount of space. Extra material necessary to support sensor as well.

Key Drawings - SolidWorks Model of keys - SolidWorks Model key insert

Key Drawing SolidWorks Model of black key with key insert, PCB board and trackball sensor

Drawing of the Key Insert

Bill of Materials

Plan for MSD II

Conclusions/Questions Electrical How to create a MIDI recognizable signal, will our design work? Choice in microcontroller Do the capacitors and resistors need to be close to the hall effect sensors? Mechanical Best way to put sensor into key?