Dotty: A new project with triggers (part 1)

After building the NanoGrids I was still looking for a nice drum trigger sequencer. I want to have a bit more control over the drum’s then the Grids is giving. And stuck in my room with Covid I started designing something. There are a few modules out there that you can buy/build. Some really nice one’s also.

The Story

A few weeks back i got sick and had to spend a few weeks in isolation. Maybe I was lucky because I didn’t get really sick and I was in a room with my computer, Kicad, Arduino’s and breadboards.

I was thinking what was missing from my eurorack and I always liked the Roland drum programming on my MC-303. I needed something like a step sequencer for my drums.

There are some out there, just to name a few: Triggerhappy (diy), Erica Synths drum sequencer (about 550 euro), Robaux SWT16+ (my fav), BigButton (lookmumnocomputer) and lots more. Still all didn’t do it for me and I wanted something a bit different. At this point I didn’t know what I wanted so I just started building something. What I did know was I needed buttons lots of them.

I wanted to build Dotty (just give it a name) with cheap parts, Arduino, led’s a few resistors, maybe some cheap dip package chips and easy to build. These where my starting point one day later it came to this.

The Leds became Led dot Matrix. These you will find on ali, ebay or other sources. A Arduino Nano and 16 buttons. It looks rubies but it works, well kinda.

The next few day’s I started programming code in Arduino Ide. Making some basic functions, using the led matrix to display it all. I now could set step, clear them and some other nice stuff you would expect from a sequencer.

When writing the code I started thinking about other functions. This lead to …more buttons. I was starting to reach the limits of the Nano. It only has a few pins. There are some devices out there that can extend these pins.

A was wrapping my head around all options, and made a few decisions. And after a few days of coding, more prototyping on breadboarding it came to this.

More buttons.. But also trigger out to test respond time of the Arduino. This was the last prototype I build. I think most technical functions are proven, the code is basis alpha version. I thought it was time to make a pcb out of it.

The design of the pcb in Kicad took me a few day. Placing all the component, footprints, silkscreens and traces.

The image is one of three boards. This is the control board. It shows 32 buttons, 8 leds, 2 jack’s in and 8 out and 3 led matrix ‘s.

These boards are production right now and I hope to get them in a week or so. If it’s like the NanoGrids I will take a few revision before releasing it someday. It’s a ongoing project and design, nothing is final.

But he there might be a new drum trigger sequencer in the near future with some features that might be fun to play with. So more to come and still a lot of work to do.

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