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DIY Stompboxes => Digital & DSP => Topic started by: MikeH on June 13, 2017, 02:20:13 PM

Title: Looking to make a MIDI clock device thingy....
Post by: MikeH on June 13, 2017, 02:20:13 PM
Ok- I haven't done any diy w/ MIDI or digital stuff, so I'm super ignorant to this stuff. Please bear with me.

I have and ehx super pulsar with tap tempo, which I thought would be awesome except tap tempo on a trem is obviously not like tap tempo on a delay, in that no matter how well you set the tempo it eventually goes out of time. Did I say "eventually?" Maybe "immediately" is more accurate. Frustrating when you're playing with a drum machine/sequencer.

Here's what I would like to build (if possible): I have a Micro Korg xl that I also use- I'd like to build a device that takes the midi out from the korg and converts it into clock/tap/whatever works for the pulsar. So I can dial in the Bpm on the korg and the pulsar will sync to the same tempo. The manual has voltage specs for the input on the pulsar, but I don't have that in front of me at present.

Is this something that is possible and/or practical?
Title: Re: Looking to make a MIDI clock device thingy....
Post by: wavley on June 13, 2017, 03:21:09 PM
Check out the Molten Voltage stuff, it should do what you need.  http://www.moltenvoltage.com/products.html (http://www.moltenvoltage.com/products.html)

He'll probably chime in here with more details.

Title: Re: Looking to make a MIDI clock device thingy....
Post by: electrosonic on June 13, 2017, 04:44:26 PM
first result from google -

http://blog.moltenvoltage.com/2015/02/sync-your-ehx-super-pulsar-to-midi-clock.html (http://blog.moltenvoltage.com/2015/02/sync-your-ehx-super-pulsar-to-midi-clock.html)

Andrew
Title: Re: Looking to make a MIDI clock device thingy....
Post by: ElectricDruid on June 13, 2017, 07:00:06 PM
I did a chip that does this job too - MIDI Clock to analog pulses. I had it in mind for analog sequencers, but it'd work for syncing pedals just the same:

http://electricdruid.net/midi-clock-to-analog-gate-pulses/ (http://electricdruid.net/midi-clock-to-analog-gate-pulses/)

The code is online, so it'll only cost you the price of the blank chip, but you'd need to find a friend/Hackerspace/someone with a PIC programmer.

HTH,
Tom
Title: Re: Looking to make a MIDI clock device thingy....
Post by: Processaurus on June 15, 2017, 06:41:26 AM
Quote from: ElectricDruid on June 13, 2017, 07:00:06 PM
I did a chip that does this job too - MIDI Clock to analog pulses. I had it in mind for analog sequencers, but it'd work for syncing pedals just the same:

http://electricdruid.net/midi-clock-to-analog-gate-pulses/ (http://electricdruid.net/midi-clock-to-analog-gate-pulses/)

The code is online, so it'll only cost you the price of the blank chip, but you'd need to find a friend/Hackerspace/someone with a PIC programmer.

HTH,
Tom

Great project, and documentation! Thanks for sharing that.

As a side question, how do you like building midi stuff in assembly language vs C?
Title: Re: Looking to make a MIDI clock device thingy....
Post by: ElectricDruid on June 15, 2017, 01:28:08 PM
Quote from: Processaurus on June 15, 2017, 06:41:26 AM
As a side question, how do you like building midi stuff in assembly language vs C?

Depends how complicated it is. For the simpler stuff, I find assembly is fine. For more complicated things, it's easier to keep track of the logic in C. For example, I did a MIDI-controlled version of the VCDO chip (http://electricdruid.net/voltage-controlled-digital-oscillator-vcdo1/ (http://electricdruid.net/voltage-controlled-digital-oscillator-vcdo1/)) so that only needed to keep track of notes-on/notes-off and pitch bend. That's ok to do in assembly. But when I came to write a full MIDI parser with control change messages and everything, I did it in C.
The other variable is speed, and on the smaller chips speed is often an issue, but in this case, MIDI is so slow anyway that it doesn't seem to matter much. Assembly's quicker, but you'll be hanging around waiting for the next byte to come in anyway, so it probably doesn't make any odds.

Tom