In this first part of Arduino Pitch Detector, I describe the hardware parts and their interconnects.\(\)
The Arduino receives input through a microphone, displays results on display and outputs the MIDI commands through USB Serial on the Arduino itself.
This project uses input from amplified microphone and outputs to a TFT display and USB-midi connection. It reuses the USB connector by replacing the firmware on the ATmega16U2 companion chip as described on the page Sending MIDI Events.
The components listed below are available from hobby stores like Adafruit and Sparkfun, or from electronic supply shops like Mouser and Digikey.
|Arduino UNO R3||$6.22|
The optional screen costs $19.95.
Notes about the schematic
For the microphone, I use the Adafruit microphone breakout. because it has a 1.25V DC bias and includes an automatic gain control. Other microphones will work for as long as they have a DC biased output, and the output signal is strong enough.
The popular Arduino UNO R3 forms the heart of the system. Note that the
REPLAY signal was only used during debugging.
If you’re going to reprogramming the Atmega16u2, you need access the companion chip header (ICSP1) as marked in the illustration below.
For the display, I chose an 1.8″ TFT LCD screen. I went back and forth between using the Adafruit breakout and Shield. The advantage of this particular LCD screen is that it comes with a library and includes a μSD card reader. The module connects to the Arduino using the SPI interface. More details about SPI can be found in the article Math Talk.
Replay Push push button
Occasionally, I use a push button to replay stored MIDI notes. The push button is active low. To use this, you need to enable USB_MIDI in the
When this switch is closed during power-up, the companion chip functions as a UART/USB-MIDI bridge. Otherwise, it does its usual UART/USB-SERIAL conversion. Refer to MIDI events for details.
The next page of this article describes the signal path and introduce the software modules.