# Spinning Disc Step Sequencer

## Overview

![](https://cdn-learn.adafruit.com/assets/assets/000/068/869/medium800/feather_IMG_3321_2k.jpg?1546925750)

Play fresh drum patterns with this 16-step disc sequencer, made with **CircuitPython** on **Feather M4 Express** and **Crickit!** It uses **reflection sensors** to read the steps marked on the paper wheel — four tracks of different sound samples can be triggered. The outer clock track keeps everything synchronized.

![](https://cdn-learn.adafruit.com/assets/assets/000/068/871/medium800/feather_IMG_3359_2k_b.jpg?1546926700)

You’ll use a continuous rotation servo to spin the disc, driven by the **Crickit FeatherWing** , plus the capacitive touch pads provide tempo controls to increase or decrease the BPM (beats per minute) of your player. **CircuitPython** code running on the **Feather M4** handles all of the coordination of the elements, and audio mixer playback duties as well.

https://youtu.be/_doZDexfNV8

Sequencers come in many forms. Today, we recognize drum machines, groove boxes, and computer DAW (digital audio workstation) software as typical sequencers. However, the player piano, with its paper roll that actuates valves and hammers to strike strings, or a music box, with its revolving cylinder or disc that plucks a tuned metal comb are also early forms of music sequencers. Our disc-based step sequencer works just like these early sequencers, but uses optical sensing to read the steps to play at the proper time.

![](https://cdn-learn.adafruit.com/assets/assets/000/068/768/medium800/feather_83120728-6F7B-481D-AEDD-398D300795A0.jpg?1546820521 Harke [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons)

## How it Works

The Disc Step Sequencer works like this:

- The Feather M4, running a CircuitPython program, tells the Crickit's servo driver to spin the continuous rotation servo, to which the disc is connected
- Five IR (infrared) reflection sensors watch for black drum pattern step marks and clock step marks (more on this later) on the disc, and send signals through the Crickit's Signal I/O pins to the Feather M4
- Each time the outer sensor detects a clock step, the Feather M4 polls the other four sensors to see if any of them have encountered a drum pattern step
- When one or more of the four drum track sensors are triggered for a given clock step, the CircuitPython audio mixer plays the assocated drum voice sample .wav files over the Crickit's amplifier to the connected speaker
- The tempo can be adjusted by touching the capacitive touch sensors on the Crickit

![](https://cdn-learn.adafruit.com/assets/assets/000/068/772/medium800/feather_disc_diagram.jpg?1546843286)

## Parts
### Part: Adafruit Feather M4 Express - Featuring ATSAMD51
quantity: 1
Featuring ATSAMD51
[Adafruit Feather M4 Express - Featuring ATSAMD51](https://www.adafruit.com/product/3857)

### Part:  Adafruit CRICKIT FeatherWing for any Feather
quantity: 1
for any Feather
[ Adafruit CRICKIT FeatherWing for any Feather](https://www.adafruit.com/product/3343)

### Part: Continuous Rotation Servo
quantity: 1
Continuous Rotation Servo
[Continuous Rotation Servo](https://www.adafruit.com/product/154)

### Part: Miniature Reflective Infrared Optical Sensors 
quantity: 1
5 Pack
[Miniature Reflective Infrared Optical Sensors ](https://www.adafruit.com/product/3930)

### Part: Adafruit Perma-Proto Half-sized Breadboard PCB
quantity: 1
Single
[Adafruit Perma-Proto Half-sized Breadboard PCB](https://www.adafruit.com/product/1609)

### Part: Helping Third Hand Magnifier
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W/Magnifying Glass Tool
[Helping Third Hand Magnifier](https://www.adafruit.com/product/291)

### Part: 5V 2A (2000mA) switching power supply 
quantity: 1
UL Listed
[5V 2A (2000mA) switching power supply ](https://www.adafruit.com/product/276)

### Part: Speaker - 40mm Diameter
quantity: 1
4 Ohm 3 Watt
[Speaker - 40mm Diameter](https://www.adafruit.com/product/3968)

### Part: Through-Hole Resistors
quantity: 1
 220 ohm 5% 1/4W - Pack of 25
[Through-Hole Resistors](https://www.adafruit.com/product/2780)

### Part: Jumper Shunt with Handle (0.1" / 2.54mm)
quantity: 1
10 Pack
[Jumper Shunt with Handle (0.1" / 2.54mm)](https://www.adafruit.com/product/3525)

### Part:  Break-away 0.1" 36-pin strip male header
quantity: 1
(10 pieces)
[ Break-away 0.1" 36-pin strip male header](https://www.adafruit.com/product/392)

### Part: 0.1" 36-pin Strip Right-Angle Female/Socket Header
quantity: 1
(5 pack)
[0.1" 36-pin Strip Right-Angle Female/Socket Header](https://www.adafruit.com/product/1542)

### Part: Break-away 0.1" 36-pin strip right-angle male header
quantity: 1
(10 pack)
[Break-away 0.1" 36-pin strip right-angle male header](https://www.adafruit.com/product/1540)

### Part: Premium Male/Male Raw Jumper Wires 
quantity: 1
40 x 6" (150mm)
[Premium Male/Male Raw Jumper Wires ](https://www.adafruit.com/product/3142)

### Part:  Premium Male/Female Raw Jumper Wires
quantity: 1
40 x 6"
[ Premium Male/Female Raw Jumper Wires](https://www.adafruit.com/product/3633)

### Part: Small Single Row Wire Housing Pack 
quantity: 1
for DIY Jumper Cables
[Small Single Row Wire Housing Pack ](https://www.adafruit.com/product/3145)

### Part: Hook-up Wire Spool Set - 22AWG Solid Core
quantity: 1
6 x 25 ft
[Hook-up Wire Spool Set - 22AWG Solid Core](https://www.adafruit.com/product/1311)

### Part: Black Nylon Screw and Stand-off Set
quantity: 1
M2.5 Thread
[Black Nylon Screw and Stand-off Set](https://www.adafruit.com/product/3299)

## Materials

In addition to the parts listed above, you'll also need:

- White letter sized cardstock or paper, 8-1/2" x 11"
- Printer for printing the disc template
- Black chalk marker for creating patterns by hand (regular markers are too shiny and don't reliably absorb the infrared light)
- Scissors
- Hobby knife
- Soldering iron and solder
- Small screwdriver
- Diagonal cutters
- Chipboard for cutting an 8" diameter disc, or
- [MDF wood circle](https://www.michaels.com/circle-shape-by-artminds/10298974.html#q=298974&start=1) from hobby store
- Glue stick
- Hot melt glue gun and glue sticks

- [Next Page](https://learn.adafruit.com/spinning-disc-step-sequencer/feather-and-crickit-prep.md)

## Featured Products

### Adafruit Feather M4 Express - Featuring ATSAMD51

[Adafruit Feather M4 Express - Featuring ATSAMD51](https://www.adafruit.com/product/3857)
It's what you've been waiting for, the Feather M4 Express featuring ATSAMD51. This Feather is fast like a swift, smart like an owl, strong like a ox-bird (it's half ox, half bird, OK?) This feather is powered by our new favorite chip, the **ATSAMD51J19** -  with...

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Sometimes we wonder if robotics engineers ever watch movies. If they did, they'd know that making robots into servants always ends up in a robot rebellion. Why even go down that path? Here at Adafruit, we believe in making robots our  **friends!**

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Customers have asked us to carry basic perf-board, but we never liked the look of most basic perf: it's always crummy quality, with pads that flake off and no labeling. Then we thought about how people **actually** prototype - usually starting with a solderless breadboard and...

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