Solder KB2040 Pins

Solder header pins to the Kee Boar (similar to this Feather configuration), then press it into the breadboard as shown in the diagram.

Prepare the AW9523

Jumper Soldering on AW9523

Solder header pins onto the AW9523. Connect it to the KB2040 with a short STEMMA QT cable, then press it into the breadboard as shown.

Solder both address jumpers on the AW9523 in order to prevent the LEDs from all lighting at startup. Soldering the jumpers sets the I2C address on the board to 0x5B which sets the chip's initial boot state. 

Play/Pause Switch

Add the tactile switch to the lower right corner of the board as shown. You'll use this to start and stop your sequencer.

You'll wire this to GND and a KB 2040 IO pin later.

Step Switches

Each PB-86 step switch has pins for the switch (both Normally Open and Normally Closed) as well as the LED anode and cathode, and these pins won't work on a breadboard, due to their arrangement. So, we made a convenient breakout PCB set for it.

You can see the full pinout info here.

Step Switch Breakout Soldering

Snap off the breakout PCBs.

Then, cut your header strip into five-pin lengths.

Place the header pins into the breadboard as shown, then solder the breakout PCBs onto them.

Place the switch into the PCB as shown and then solder all six legs.

Repeat this process for the remaining fifteen switches, then you'll add them to the breadboard and start wiring them as shown in the steps below.

Breadboard Wiring

Switch Wiring

Start with the GND and LED + connections to the breadboard power rails -- making short wire "staples" helps to keep things neat.

Switch Wiring Continued

Wire the KB 2040 GND and 3v3 pins to the breadboard power rails as shown. Remember to connect all of the breadboard power rails to each other.

Wire the bottom row of switches as shown here, connecting their normally open (N.O.) switch contacts to the GPIO pins of the KB 2040.

Be methodical and careful about it, since there is quite a lot of wiring it can become confusing to troubleshoot later!

Play Button and Switch LED Wiring

Connect the play button as shown here.

Wire the LED- pins from the switches to their associated pins on the AW9523. These will drive the current for the LEDs.

Top Row Switches

Next, you can add the top row of switches and wire them the same way you did with the bottom row, but all going to their own pins on the KB 2040 and AW9523.

Add the Display

Add Display

Plug the 14-segment LED backpack into the AW9523 with a short STEMMA QT cable. Also, plug in a longer cable at this time that will connect to the rotary encoder breakout.

Due to the position of the STEMMA QT connectors, the board can't lay flat on the breadboard, so you'll mount it on the overhang of the breadboard.

In order to secure it to the board, create some "staples" with pairs of pin headers modified as shown. You could alternatively use double-stick foam tape, hot glue, or another method.

Add Rotary Encoder

Connect the rotary encoder to the STEMMA QT cable coming from the 14-segment LED backpack.

In order to secure it to the breadboard, solder pin headers and press it into the breadboard as shown.

Your build is complete -- this is a good time to use a continuity tester to double-check that you don't have any shorts from power to ground. Next, move on to coding the Drum Sequencer!

This guide was first published on Jan 11, 2023. It was last updated on Mar 25, 2024.

This page (Build the 16-Step Drum Sequencer) was last updated on Mar 08, 2024.

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