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Recent progress
Some projects I’ve been working on of late:
- Made some progress on the MIDIbox SID – I did some more work on getting the enclosure(an old 2U satellite receiver) ready and figured out the next batch of parts necessary to get it completed.
- Did a serious revamp on the Arduino Sequencer last night – it now has a power switch, start/stop switch, and two indicator LEDs (built into the start/stop switch). I also attacked the code pretty extensively to account for these new features. It still needs some tweaks, but once they’re done I’ll post the code here.
- More-or-less finished the Arduinome I’ve been poking at since January (longer if you include parts accumulation- I got the unsped shield & MAX7219 over a year ago). It still needs a little mechanical work- it as yet has no base, and no hole for the USB cable, but it’s pretty much together and usable.
Still plenty of other backlog to clear, and reissues to reissue.
I leave you with a video of the Arduinome in action:
RPM Challenge – my personal 2010 rules.
As I’ve sort of mentioned before, I’m taking a ‘sabbatical’ from most of my DIY activity next month in order to record an album for the RPM Challenge(my third). It won’t be completely ‘cold turkey’, so don’t worry about me – I will allow myself a little hack time at the project nights popping up with the Cleveland Hackerspace community that’s starting to come to fruition. But no PCB soldering – that’s right out…
Rules for the album that I will be recording:
1) Basically all DIY gear. That means built, repaired, or modified by me. Since I’ve fixed my DR-110 and my MG-1, they’re fair game. The DR202, which has had nothing done to it, isn’t, so I can’t use it.
1a) Non-DIY microphones are allowed this time. Signal Intercept only used a DIY’d contact microphone for bizarre reverb purposes, but I’m going to allow real mics this time, if for no other reason than to use my newly finished PAiA Tube Mic Pres…
1b) I will allow myself the use of one MIDI controller keyboard – the Alpha Juno-1, and only used for MIDI notes – not as a synth.
1c) computer-based patch editing on the MIDIBox SID is allowed, since I don’t have a control surface for that done yet.
1d) computer-based recording is allowed, if for no other reason than digging up blank tapes for the four track is a pain. I’ve also built my own USB interface, so that’s a good reason too. No plugins though. Just use the computer as a straight-ahead multitrack recorder.
2) Since I have a DIY sampler now (the WTPA), in theory I could just sample a non-DIY instrument and call it a day. I think that for non-DIY instruments or samples from somewhere random, that the sample shall have to be captured into the sampler using a microphone, just to add some complexity. Sampling the modular or a DIY instrument can be done direct.
Any other rules I should impose upon myself?
And finally, in other news, the Arduino module I’ve been prototyping for a few weeks is now somewhat operational – in a “still on the breadboard, getting power from the laptop” kind of way – but operational enough to use it next month.
Arduino Trigger-to-MIDI converter
OK, the trigger-to-MIDI clock converter seems relatively happy (though I think the MIDI in on my AN200 isn’t? That’s going to require some more tests…).
I hacked on it a bit tonight trying to determine how drifty the generated MIDI clock was relative to the incoming trigger pulses from the DR-110. At first it was pretty ugly. I then added some compensation to the clocking to account for all of the work the Arduino is doing. After some trial-and-error, it’s relatively tight – total drift by my rough calculations was something like 10 milliseconds over a five minute period. Compare that to an earlier drift of 120 ms in a minute…
Here’s the code: trigger2midisync.pde
Hardware-wise, there’s a trigger input on pin 2 (use a zener if you’re worried about blowing stuff up…), and the MIDI out is the standard (TX, GND, and 5V through a 220 ohm resistor going to the pins of the MIDI port).
You may want to configure some of the #define statements in the code. STOP_TIMEOUT is the amount of time that needed without triggers needed for the converter to decide to stop. I’m using 2 seconds. Changing DIVIDE_SLICE would be important if your trigger source is something other than 4ppqn, and CODE_OVERHEAD_TIME is used to adjust drift in your deployment – 10 worked really well for me in my tests tonight, but it could be anything for others.
Once it’s hooked up and connected to your MIDI source and your trigger source, start sending a series of pulses to pin 2. On the first pulse, MIDI Clock start should get sent, and by the third pulse or so the sync will be “synced” – there will be an offset, but it should remain fairly constant. Now, once the pulses stop, clock will continue to be sent until STOP_TIMEOUT milliseconds have passed.
Next test will be syncing the DR-110 to the very-nearly-finished x0xb0x to see how well that keeps up – I did all my tests tonight with a Yamaha RY10, with both it and the DR110 just playing a “four on the floor” kick pattern.
Questions? Comments? Improvements?
Building building building…
Been a while since there was an update, so let’s see what’s on the bench of late:
- x0xb0x – Yeah, I took the plunge and self-sourced a kit (not that hard since there’s a guy on the forums selling the rare parts kit for a reasonably fair price). It’s soldered up and mostly working, except for an extremely weird intermittent problem I haven’t completely solved yet. It’s unclear what the actual problem is, but I think I have a pretty good workaround ready to go. I also had issues with the USB chip early on, and then pulled since it was highly suspect when I first started having trouble. Now I’ll have to try to re-solder it again…
- Haible varislope filter/phaser – Pretty much done! I think I need to reverse some of the pots and adjust some things, but it’s working reasonably well.
- A trigger-to-MIDI Sync converter – Decided to do this with an Arduino so that I could at least clumsily sync my DR-110 to other stuff (x0xb0x, AN200, etc.). Code will be posted soon, once I add in start/stop functionality and test it a bit more thoroughly.
- MIDIBox SID – I’ve got the CORE, SID, LCD, and a pair of Banksticks up and running. Worked great under computer/MIDI control, though I think a noise gate will be necessary for the bad 6581 VCA. Waiting for DINx4 and DOUTx4 boards, and then I’ll have to figure out the control surface – it will be more complicated than the basic one, but less complicated than the “full control surface”.
Whenever the PCBs show up, I also plan on building a pair of XR2206 VCO modules, as well as a few other modules on the horizon. Gotta start thinking about a new rack as well. I’ve got the first pair of Vector rails, but lining it all up is going to be careful work.
Also coming soon: A pair of PAiA Tube Mic preamps- the phantom on my mixer died (just as I got some condenser mics! curses!), so these are going to replace that functionality. I’m going to hotrod them a bit with better parts and some ECC83 tubes to replace the 12AX7s it ships with. Ordered some pedal PCBs as well – a Big Muff Pi clone, and a Rebote 2.5 delay.
I think I’m also going to have to move the electronics area to a bigger room with bigger tables, but that’s probably at least a month or two out.
post-weekend project update
Well, since issuing my March Manifesto, I think I’ve managed to break both rules so far. Excellent! Bear in mind, the parts were semi-unobtanium for cheap (CD4006′s and a 74C922 – fifty cents apiece!), and the new project is something that isn’t going to happen any time soon (an Arduinome – I ordered the shield PCB, and I have a MAX7219. That’s going to be the extent of its progress for quite a while. Must. Clear. Module. Backlog. First.)
I did make some progress on the USB audio interface, but at the moment, it’s only usable as an incredibly expensive USB-powered LED. Not Good. I’ve painstakingly continuity-tested all the traces on the PCB to pins on the PCM2902, and those all check out, but there may be a bridge or something along those lines, or I fried the chip. But so far, it’s getting power from USB, the LDO voltage regulator is working, and maybe the IC is doing something? I’m seeing Vccci/2 on the Vcom pin, but the board isn’t getting recognized by either of the computers I’ve attached it to. Frustrating.
In a worst-case scenario, I do have another PCB (cost me just as much to get two as it would have one), and another PCM2902 (yay pairs of samples!). So I can either build a second one, try the other chip in this one, or some strange combination.
In preparation for whatever I decide to do, I was looking around the Curious Inventor site at some of the surface-mount soldering tutorials, when I found this. I then ended up running out to my local fabric store and finding a slightly different model (a Darice Craft Heat Tool, which is from an Ohio-based company, and the unit is made in Taiwan, in case anyone is looking and wants to know such things.) I haven’t tried using it to solder anything yet, but I did desolder some surface mount parts from a scrap PCB, and it worked really nicely.
I also attempted to get some aluminum panels for various projects, but failed – the posted hours for my local Metal Supermarket didn’t match reality. I will be going back on Friday.
And lastly, I came up with some more ideas I’m not implementing any time soon – a smallish “Analog Computer” module (say 4 op-amp’s worth, think this but way simpler), and a rather crazy Lunetta panel (not sure if I’ll fully do it the way I envisioned – maybe if I can find an ALU chip (74181 or the like) for cheap…)