Business Card Sequencer

Business Card Sequencer

Boards for this fun little sequencer, which can also be used as a tiny keyboard, were handed out to everybody who attended Knobcon 2016. If you're wondering what to do with your board, or want to get one of your very own, you've come to the right place.


Connections, From Left to Right

Power In: 7-15VDC, tip positive (Don't reverse it or it will get mad). Just find a voltage source on your synth somewhere. If the notes being played by the sequencer seem flat, the power supply you have chosen may be dropping too much under load. If you can't or don't want to use your synth to power the sequencer, you can use a 9V Battery or AC power supply.

Clock In: 0-5V is ideal, but going outside that range won't hurt it. Step will advance on rising edge.

CV Out: 1 volt/octave, C=1V/2V/3V. Connect to the CV in on your oscillator (or filter or whatever)

Gate Out: On=+5V. Plug this into your VCA, EG, etc. Gate timing follows the clock when the sequencer is running, buttons when in Ready mode, and stays on while programming.



Push Run to start playing a sequence. The true green Run LED will light to tell you that you are in Run mode. Push it again to Pause. The sequencer steps can be programmed while paused.

Push reset to stop the sequence, go to step 1, and enter Ready mode. The blue step LED will blink to let you know that you are in Ready mode. This means that when you press Run again, the sequencer will play step 1 on the next clock pulse instead of skipping it and going to step 2.

If you want to start on a different step, you can use the step left and right buttons to pick a different one.

While in Ready mode, you can use the note buttons to manually play tunes without messing up the sequence you have stored in memory. Gate timing will follow your button presses.

Programming is done while the step LED is steady (not Ready mode) and the sequencer is not running. You can enter Programming mode by pressing Reset a second time, or pausing a sequence with the Run button. Use the step left/right buttons to pick which step you want to program, then press the note you want that step to play. The new note is automatically stored in non-volatile memory.

Remember about the step LED:

  • Blinky = Ready Mode = Will start on selected step = Can play keyboard live
  • Steady = Programming = Any notes you push will get saved in that step

The sequencer keyboard covers 3 octaves, so you can use the octave up/down buttons to transpose the keyboard up and down. The green and orange LEDs will tell you which octave the keyboard is currently set to.

In addition to standard notes, you can also program a Rest or a Loop command into a step. A Rest step holds the previous note and doesn't fire the gate. Loop makes the sequencer go back to step 1. You can use this to create any length sequence you want. For example, if you only want steps 1-13 in your sequence, you would make step 14 a Loop step.

Starting with firmware version 1.1, the sequencer operates with a built-in clock from power-up until it receives its first external clock pulse. The internal clock rate can be adjusted up and down while the sequencer is running using the step buttons. Once the unit has switched to external clock mode, the internal clock can be restored by holding down the reset button for about 2 seconds (soft reset) or removing/restoring power to the unit.

If you received your parts kit at Knobcon, you have firmware v1.0. If you wish to have internal clock functionality, contact us and we'll figure out a way to make that happen. If you ordered your parts kit online then you already have firmware v1.1.


Getting Parts

You can get the complete sequencer kit at any of these vendors

Here's a BOM if you want to source your own parts:


RefDes Part Value Qty Vendor Vendor Part No.
C1 Ceramic Capacitor .1uF 1 Mouser
C2 Electrolytic Capacitor 10uF 1 Mouser
D1 LED, 3mm White 1 LED-Switch
D2-D17 LED, 3mm Blue 16 LED-Switch
D18-22, 25-31 LED, 3mm Yellow 12 LED-Switch
D23 LED, 3mm Orange 1 LED-Switch
D24 LED, 3mm Green 1 LED-Switch
D32-33 LED, 3mm Red 2 LED-Switch
D34 LED, 3mm True Green 1 LED-Switch
D35 (if present) 1N4148   1 Mouser 512-1N4148TR
J1-J4 3.5mm Jack   4 Mouser
PCB1 PCB   1 Division 6 BSEQBOARD
R1 (if present) Nothing NO   Move along Do not populate!
R2-R3 Resistor, 1/8W 1K 2 Mouser
R4, 6-9 Resistor, 1/8W 100-ohm 5 Mouser
R5 Resistor, 1/8W 100K 1 Mouser
S1-20 Tact Switch 6mm 20 Mouser
  1 Mouser
VR1 L4931CZ50 or 78L05   1 Mouser



Business Card Sequencer

Note: You don't have to use the same LED colors we did; you can use any colors you want. Here's what we picked:

  • Clock: White
  • Steps: Blue
  • Notes: Yellow
  • Loop/Rest: Red
  • Octave Down: Orange
  • Octave Up: Green
  • Run: True/Pure Green

Assembly is fairly straight-forward; solder the parts in from shortest to tallest so your workbench will hold them in place when you flip the board upside-down to solder:

  • Resistors (polarity doesn't matter) and diode (if present; make sure stripe on diode lines up with stripe on silkscreen)
  • LEDs (Short pin = negative(-) = flat side = square solder pad)
  • IC (pin 1 goes toward CLK IN jack)
  • Ceramic Cap (polarity doesn't matter)
  • Jacks
  • Voltage Regulator (be careful soldering this; the pins are very close together!)
  • Electrolytic Cap (negative (-) stripe/short lead goes down toward IC)
  • Buttons

For a visual BOM and more detailed assembly instructions, download the PDF version!


Programming the PIC

You can either get pre-programmed PICs from one of these vendors (or see complete parts kits above), or you can download the code (v1.1) and program it yourself. Depending on your programmer, you can either do it before you solder it to the board, or you can use the ICSP port on the left side of the board to program it once it's already on the board:

Pin Function
1 (Square) Vpp (MCLR pin)
2 +5V (Vdd pin)
3 GND (Vss pin)
4 Data (PGD pin)
5 Clock (PGC pin)
6 <NC>



If you want to mount the board behind a panel or in a box, here is a drawing of the panel component layout.

Business Card Sequencer Panel Layout



An enclosure kit is now available for the sequencer. The top panel is a PCB, and the sides and bottom are made from laser-cut acrylic.


Enclosure Kit