Thinkertank’s Chess Sequencer is a step matrix sequencer made from a chess board.

Placing chess pieces on the board switches notes on. In the demo above, the sequencer is being used to control software synths on a Mac via USB.

Features:

• Key – The key switch is a 12 step selector switch, where you can select every half note from C to B. The software lets the key wrap so that if you continue to turn it clockwise you will getting higher and higher octaves. Counter-clockwise gives lower and lower. This way you can transpose to all octaves and notes in the midi range.
• BPM – A potentiometer let you slide from 20 to 220BPM. This range can be altered in the top of the Arduino code to anything you like.
• Stroke – This is an important feature. If you have several pieces in the same column and the stroke knob is heading straight up, the notes will be played simultaneously. If you put the stroke slightly to the left, they will be played from top to bottom like an upstroke on a guitar. Slightly to the right will be like a downstroke on a guitar. This sounds a bit like a music box, where only one note is played at a time. If you set the knob to the extreme left or right, the notes in the column will be divided equally time wise on the available time to the next note. Example: Given that a column represent an 8 note, two pieces in the same column will be played as two separate 16?s after each other, three pieces as triplets, four pieces as 32?s etc.
• Steps – You have the possibility to adjust how many columns to playback, from 8 to 5, so you can make odd rhythm figures. I am using the same 12-step switch as the Key selector, so I think I will expand the possibilities with this knob later.
• Echo – A potentiometer lets you analogly choose delay time, synched to the BPM, for a midi echo. That is that every note is repeated one time with a lower velocity. Turning it ccw turns it off.
• Hold / Pause – This is a three-step switch. In the middle position all is played normally. Pulling it down will stop the playback. Pending echos will be allowed to finished. Pushing it up will freeze the play fields and controls until you put it in middle position again. This give you possibilities to make changes while the sequencer keeps playing the last setup. Then, when ready, you can apply the new setup.
• b / bb – These three stage switches let you pull the note for each row down a half or a whole note. The default scale with all switches up is a whole step scale sounding kind of eerie. By setting the switches you can make it play most scales.

See the Thinkertank site for details.