Hardware Requirement​

  • TI CC3200 Launchpad x2
  • A wireless AP
  • Amazon Web Servers (AWS) account
  • Ultrasonic Distance Sensor RCWL-1601   
  • Adafruit VS1053 Audio Codec  

Part A

Functionality

  • ​Sense the distance between the hand and the head of the instrument,
  • Translate the number into a note,​
  • Send the note to the cloud.

Implementation

  • The distance sensor is powered by a 5V voltage source. It has a trigger pin which is an output signal from the board to the sensor send the ultra-sound signal to measure distance in coordinated with a timer on the CC3200 board
  • The AWS is used by creating a thing with three certificates and flash them into the board to enable to connection, use http_post to send the note variable to the cloud and update the thing status.

Part B

Functionality

  • The user interface is implemented with UART that instruct the user to switch instrument type and play the note.
  • Play this instrument by shifting the position of your hand on the left and plug the string on the right, which the movement on the right hand is read by an accelerometer and therefore trigger the corresponding sound.
  • The sound is then outputted though the audio jack to earphones or a guitar amplifier.

Implementation

  • The MIDI is supported by a 5V voltage source. Five MIDI functions are used in here to set the instrument, set the channel, set the volume, play a note and stop playing a note. The communication between the board and the MIDI is via UART channel 1, which is set to be pin7 on the board as a TX and connected to the RX pin on the MIDI. 
  • The error message checks are implemented to make sure that the user can only enter mode 1 and 2 when in the menu, and can only enter a instrument number that is valid for MIDI when it is in mode 1.
  • The AWS is used by creating a thing with three certificates and flash them into the board to enable to connection, use http_get to get the note variable to the cloud and input the note to MIDI
  • The accelerometer is communicating with the board via I2C. The data of three axis are transmitted in a single package and parsed to read x, y, z axis separately. When the x axis receives an increase of acceleration, which indicate that the pluck of a string happened because the hand starts to move the sensor with a notable speed, the sound is triggered. The threshold is set to 60 at this point.
  • The output is connected to audio jack that has three pins: ground, left channel and right channel.