http://www.beat707.com"This project was brought to my attention a month ago and it immediately caught my eye as a perfect solution for a sequencer for my 9090 TR-909 clone.
Quick Run Down:
The Beat707 is a Arduino shield (meaning hardware front end) and software for an Arduino (Uno/2009/Mega) hardware platform. The Beat707 hardware can be purchased via their website assembled for $100 (An Arduino MIDI Groove Box Shield). Their website has a number of video demos that I recommend everyone check out. An arduino will run you $15-$65 depending on what you get and where you get it. I opted for an Uno for $30 but am upgrading to a Mega since the code limit for the 2009/Uno has pretty much been met. Anyone looking into getting one, I recommend a mega (Chinese clones are ~$40).
The hardware is simple to assemble, simply join the Arduino and the Beat707 (pins and headers) and upload the software. Arduino has its own software to upload the apps to the hardware and it is trivial to use (no programming knowledge required)
The Hardware:
The controls are straight forward. Sixteen step buttons, 4 navigation buttons, Stop/play/record/shift. Ports are midi in/out, Power, USB. It can be powered via USB and it also has a midi over USB function.
Here is mine. I opted for different style buttons from the kit to better suit my case. I also have two mods installed (more on that later)
The software:
The sequencer consists of 18 tracks: 14 drum instrument tracks, 2 monosynth tracks, and two accent tracks. Each drum voice can be set to a different midi channel and note. The names can easily be edited in the software so you don't have to have them named according the to GM names.
Editing the drum tracks is pretty much identical to the Tr-707. There is a A/B variation for each track giving a total of 32 steps (and it even goes beyond this, however I have not played around with that feature). The combination of the shift key gives access to editing and quick jump parameters (copy/paste/mute/solo etc). Pattern edit mode is your classic x0x style editing and there is also a realtime record where each of the 16 keys represents and instrument (again, like the 707)
The two synth tracks work considerably differently than the drum tracks and each note is entered per step and remains on until a note off event is programmed (to hold notes) or another note begins. There is also a slide function to slide between notes. What I really dig about the synth tracks is that with a keyboard attached, you can simply play in the notes from a keyboard. A clever scheme is used where a light note press (low velocity) is recorded as a rest and a hard press records that note. Both events advance the sequence to the next step. Quite fun to use.
Hacks and Mods:The designer built in quite a bit of expandability so it is very easy to add features. Like I show above, I added an analog pot (which can be assigned to a number of parameters) and an encoder which allows for quick editing of parameters. There are also a number of switch inputs that can be used for a variety of things (footswitch start/stop). Trigger outputs are also built in to trigger non-midi external drum voices.
At this time, there is no case or faceplate for the Beat707 (coming soon afaik) so I designed my own enclosure based on an extruded Hammond box and a CNC made panel. I used lightpipes for the LEDs since they are mounted to the board and SMD parts."
