The Haydn Step Sequencer

Current Status:

• Last updated : 02-Feb-23
• 1. Most of the front panel hardware had been fully debugged although there was an issue with some of the LEDs that were not as bright as they should have been, probably because they were hard-wired to the Mega2560 processor and its pins can't supply much in the way of current. A simple transistor buffer was on the test bench to boost the LED brightness but I felt that this was unnecessarily complicated and spent some time hunting down a couple of ultra bright LEDs.
• 2. The analogue-style faders were working nicely. There was a minor ghosting problem although it was judged insignificant.
• 3. Timing was spot on across all four MIDI channels.
• 4. More work was required on the editor pages. One or two were in the wrong place.
• 5. The LCD Placement wasn't perfect and there were issues with the contrast on some models.
• 6. The Desktop model had a really nice silk screen front panel although the rack mount was still blank.
• 7. The Mega2560 processor wasn't able to support USB and this instrument needs USB.

Next steps:

• 1. Figure out what's left to do on the software
• 2. Design the USB protocol etc
• 3. Design a new CPU card around a Teensy 3.5
• 4. Solve the LCD mounting issue
• 5. Finalise the artwork for the rack-mounting version and get the panel printed up
• 6. Design an enclosure for the rack-mounting version
• 7. Fix the desktop enclosure so it doesn't suck and fall apart

The current version uses an Arduino Mega2560 as its central processor. I can either leave it as it is and just finish the existing system or we can take a small risk and port the software to a Teensy 3.5, which is +5v tolerant and will work with the current hardware but also gives us USB support. Which direction we go will depend entirely upon how important USB is for this machine. What do you think? Let us know.