PB204 Sync Sequencer

There is a new version of the sequencer use the PB206 Sequence (Total) Recall instead

That is the latest 8 step sequencer for the Paper Bits. One can change steps, speed and the value of two independent CV output. Because it has an external trigger input one can easily synchronize them. It's evan possible to build an 16, 24 or 32 step sequencer out of two, three or more of them.


Assigning CV

Set the MODE switch to CV.
To change the output for each step one select a value with the BEAT/CV potentiometer and in pressing the button for a specific step the selected voltage will be assigned to that step.
Depending on the selection of the CV switch it will be independently stored for the output 1 or 2.


Set the MODE switch to BEAT. Now one can change the length of each step. One can select a value by rotating the BEAT/CV potentiometer and in pressing the button at a specific step the selected value will be assigned to that step.
It just will work if the Ex-Trigger switch is OFF.


To change between 2 and 8 steps one can use the STEP potentiometer.
If one select 1 step the Sync Sequencer goes into the 1 STEP MODE. By rotating the SPEED potentiometer one can now move to each individual step. That makes it much easy to program the sequencer.

Change the Speed

The speed of the sequencer can be changed with the SPEED potentiometer or with an external control voltage. For the external control the EX-SPEED switch has to be on ON and with a jumper one can choose if the voltage source coming from BUS 1 or BUS 2.
If the Sequencer is in the STEP 1 MODE one can change the active steps with the control voltage, too.

External Trigger

If one wants to use an external trigger signal one has to set the Ex-Trigger switch on ON. If the TRIGGER jumper is set the trigger signal will come from the GATE BUS. If the jumper is not set then one can use the pin marked with IN for a trigger signal input.



  • Resistors:
  • 8x 220 Ohm
  • 3x 10 kOhm
  • 3x 1 kOhm
  • Capacitors:
  • 2x 22 pF (ceramic)
  • 3x 100 nF (foil)
  • 1x 1 nF (foil)
  • Electrolytic Capacitors:
  • 1x 2200µF
  • 1x 10 µF
  • Diodes:
  • 8x LEDs 3mm
  • Crystal:
  • 1x 16 Mhz
  • IC:
  • Atmega328P-PU
  • Mechanical:
  • 1x 28pin IC socket
  • 1x pin strip 1×14
  • 2x pin header, female 90° 1×3, 1×2
  • 2x pin header, male 90° 1×3, 1×2
  • 9x push buttons (2 pins)
  • 1x mini switch
  • 5x jumpers
  • Potentiometers:
  • 3x 10k


Once you're board is ready, you will need to burn the Arduino UNO bootloader on the Atmega328 chip (some chips already come with a bootloader).
Follow the instructions to burn the bootloader:
burn the bootloader

Insert the chip into the IC socket and connect it to you're computer using a USB to Serial board. For example one like that: Arduino USB Serial or that one: Sparkfun Breakout Board Here is a manual for doing so: https://www.arduino.cc/en/Guide/ArduinoProMini
Or use your Arduino as a Serial Adapter

Open the Arduino IDE software on your computer and upload the following code to the board (Arduino UNO): syncsequencer_03.zip

and voila ready to step!


The PB204 Sync Sequencer was designed by Wolfgang Spahn, 2019-20.
It is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Creative Commons License