Digital I/O
Creating a noise generator and step sequencer
This lecture explains how to work with digital input and output on Bela. Like Lecture 6, this lecture involves building simple circuits on a breadboard to connect to Bela. In this case, the lecture focuses on gates and triggers in modular synthesis using the digital I/O pins with a pushbutton.
Table of contents
- What you’ll learn in this lecture
- What you’ll make in this lecture
- Code examples
- Recommended parts
- Additional references
Lecture 7: Digital I/O
What you’ll learn in this lecture
- Digital inputs and outputs on Bela
- Working with pushbuttons
- Gates and triggers
What you’ll make in this lecture
- A noise generator and a step sequencer
Code examples
digital-io: A complete example showing digital input and output with a white noise generator.
step-sequencert: An example to be completed during the lecture, using a button press as a trigger to advance a step sequencer changing the frequency of an oscillator.
Recommended parts
Running the examples in this course assumes that you have a Bela Starter Kit or Bela Mini Starter Kit. Note that the analog outputs are only available on the original Bela board, and not on Bela Mini.
This lecture also uses several electronic components:
- Solderless breadboard (Rapid, Adafruit)
- 1x pushbutton (Rapid, Adafruit)
- 1x LED (any colour) (Rapid, Adafruit)
- 1x 10k resistor (Rapid, Adafruit)
- 1x 220 ohm resistor (Rapid, Adafruit)
- Jumper wires (Rapid, Adafruit)
Additional references
Working with electronic circuits
- Breadboards for beginners by Adafruit
- Voltage divider tutorial by SparkFun
Sensors for audio and music
- Introduction to potentiometers by Rod Elliott. Contains a deeper dive into the how and why of potentiometers, especially for audio.
- SensorWiki by the Input Devices and Musical Interaction Laboratory at McGill University. Surveys the sensors used in digital musical instruments.