I’ve become slightly obsesessed with this little Palm OS Sequencer from the distant past. So I thought I’d share a bit about what it can do:

Hedgehog is a pattern sequencer for MIDI-enabled hardware and software that runs on your Palm Pilot. To use Hedgehog, you need some sort of MIDI interface attached to the serial port (the thing the Hotsync cradle or cable plugs into.) Hedgehog sequences 16 1/8th notes (‘ticks’) per pattern and can chain up to 12 patterns in a larger loop.

Each pattern can support 2 discrete channels of MIDI information, and each tick can also send out up to 16 controller messages, to sequence effects or synth parameters with your note information. This is
where Hedgehog is great fun. Hopefully, your gear already supports MIDI controller automation.

The note information is entered on the screen, and can be changed while the sequence is playing.
The ‘X’ on the left represents the state the system is in, you can be in “add note on”, “add note off”,
“add single hit”, and “delete note” mode. The last row of the control bar determines which channel
the data is being changed for. In this manner, you can control perhaps a drum machine and a
synthesizer separately but on the same page, so you can see how the pattern will sound before you
hear it.

Notes that are for channel one appear towards the left of each grid space, and notes for the second channel appear towards the right. As well, a special area to the left of the note editing grid is set aside for octave shifting. If you tap towards the right of the note grid, you can get either an up or down arrow which shifts that note (for just that pattern) up or down an octave. This is great for making dual bassline and melody information, or even just for marking “valid” notes.

The controller information is entered by dragging your pen across a controller bar below the note entry grid, or just tapping each tick’s individual section. There are 16 controller states the sequencer sends out at each tick. Using this system, you can do crazy things like sequence panning information or volume, or your effect’s reverb level per note, or filter level for your samplers… the possibilities are endless. Each square in the grid represents a different controller type, and controllers can also be browsed and changed while the sequence is playing.

Even more fun is the Tweak Bar at the top of the screen. As the sequence is playing (or even when it’s not), you can twiddle the pen over the Tweak Bar to dynamically send controller messages of the type currently selected onscreen. So in addition to the sequenced controller changes, you can “jam” along on another controller. Sequences are made up of groups of patterns. Each pattern can be viewed by tapping on its box at the bottom of the screen. Of course, you can view and edit other patterns that are not playing at the time. A small dot indicates which pattern is being played at the time, however. You can define the start and end position of the sequence loop by using the start/loop/start bar to the right of the sequence bar. Sequences can be from 1 to 12 bars long and can start and end anywhere among the pattern list.

To start, stop, or rewind the sequence, use the transport bar at the left of the screen. This works just like everywhere else you’ve seen it. It also sends out the proper MIDI Realtime messages upon restarting the sequence (hitting rewind while playing) or continuing (hitting stop, then start again) it. As well, you can change the BPM of the sequence here as the sequence plays and view it onscreen.
Lastly, Hedgehog also does some things that no other pattern sequencer does. The Math Bar to
the right of the pattern list can alter your sequence in varying ways. It can randomize the sequence completely from a new seed (either the controller set or the note set, you choose by marking the rightmost box) or vary it only slightly using a Markov chain model. This of course can happen during sequence play.

So, as you can see, even for a very simple little Palm OS App it can do a lot. I plan to do a bit more with this soon and have a few more videos of it controlling stuff, so expect to see it in action again soon.

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