Mac Mini, MIDI and monitorless use

Tonight was frustrating all around.  It totally sucks when your programming and the equipment is all set up correctly and then what appears to be an OS issue gets in the way.  We have a brand new Mac mini running OS 10.7x for driving installations.  Works great until we unplug the monitor.  Once that happens the MIDI stream freaks out, slows down or otherwise doesn't do its job.

After doing web searches and trying various attempts to "trick " the computer, I opted to take apart a cheap VGA flat screen so we can fit it in the security box.  A student show is being installed and failure is not an option.  How demoralizing would it be to get all that stuff in order and then be defeated so capriciously.  I am a firm believer in testing and making sure stuff works.  It is awful to walk into an interactive show and then not understand what is going on or to have the interactivity not function because of a computer crash etc.  Things must work!

So,   the immediate problem appears solved.  Now to find out a real solution.  I have posted to cycling74's forum and am crossing my fingers hoping an answer will be forthcoming.

Sound as a trigger and Solenoids

After a review of the videos being produced by the class, I asked the Core group to build up a program to control the tripping of a solenoid attached to a rudimentary lever arm.  After a couple of dead ends they got it to trigger.  Just for fun I added onto the patch the ability to trigger the device by using a microphone and loud sounds.  This clip shows just that.

The solenoid is a 12volt Dc device tied directly to a wall wart power supply.  This device is plugged into the Elation Cyber Pak.  When the AC channel of the pack turns on, the solenoid is powered and thus pulls shut.  Even so, it may not have the power needed for the student project I had envisioned, plus it is very noisy making a loud "thunk" when tripped.  Regardless, the thing is a riot.  It was especially entertaining when shouting for a while when one of the full time faculty (Valerie Mendoza) stuck her head in through the side door, no doubt wondering what the relative shouting and other vocalizations we were doing to trigger the thing.

The cool object for the night was the "split" object allowing a range of numbers to be selected.  The other odd discovery was the arm not triggering when the lights were off (we had attached a lit candle to the arm end).  We found that the Miditron was still active with a photo cell sensor.  This overrode the audio trigger.  Another good nights work.    Next will be motors.

Miditron and Potentiometer

Made some excellent progress this evening.  The Miditron PDF is pretty thorough and simple, this is why I couldn't quite figure why it wasn't performing the way I expected.  We had a photo-resistor in terminal one that I could only get to read in digital mode.  It just wouldn't give any information when set to analogue in.  I had assumed that this was because I didn't know the resistance of the component.  Tonight we had the photo cell in terminal one and a 100k ohm Pot in terminal 3.  Not working except in digital mode.  After re-reading the documentation we moved it to terminal 2 as the terminals must be used in sequence.  After this also failed, I reset the board to factory default.  Instantly we were getting analogue readings on terminal one.  When I switched it to digital and and term 2 to analogue, term two did not read.  The lesson is the terminals must be set to the same mode to function.

After this minor discovery, we were good.  With the pot functioning I threw together a quick patch allowing the control of ann audio files playback speed.




Here is the image of the patch used for making the sounds.  Super simple.  Had terminal two set to "control change"  and used that to control the playback speed of the file via an SfPlay object.

Tonight we made headway in figuring out the Elation Cyber Pak 8 midi/dmx dimmer pack.  The core group ( the three students and myself that are working out the bugs of the software and hardware before  teaching it to the rest of the class )  started going through the dimmer documentation.  It is pretty thin at best, it took us a while of trial and error and web searches to determine the device responds to only one midi channel and the dimmers are tied to a single midi note.  If the pak is set to 4 channel, then midi notes 1 through 4 are used.  As the velocity of the note is increased, so is the power to the channel.  We were using the noteout object in max.  I am almost certain I can use the midiout object.  The immediate issue with the noteout object is that we get pulses of whichever duration is currently set.  The next thing to test will be if I can just send a midi note on and then a midi note off as distinct events.

The rest of the class is engaged in the first of the video projects.  An essential "warm-up" exercise in Adobe Premiere.

Video of tonights work.