Tuesday, March 18, 2014

Brain Computer Interfaces (BCI)

Commercially available, relatively low cost Brain Computer Interfaces (BCI) and related software

Is it possible to create music with brain waves? It's a work in progress.

You can find all of my links here : http://delicious.com/tkarches/search/EEG

An incomplete summary :

Mindwave Mobile (Neurosky)

  • Retails for $99 (Brainwave Starter Kit)
  • Works with Mac, Windows, iOS, Android
  • A number of iOS apps (search iTunes store with "neurosky") - most cost $$$
  • Brainwave Visualizer (Mac, WIndows) shows all brain frequency bands - almost too much data
BioZen software : http://www.t2.health.mil/apps/biozen
  • Neurofeedback software
  • Free
  • Developed by the military to help soldiers
  • Runs on Android devices
  • Most input devices supported are based on Neurosky headsets

MindFlex and MindFlex Duel - Toys by Mattel that use the Neurosky electronics. Only uses Attention parameter. Headsets can be modified for full EEG output. These are available relatively cheaply on eBay and Amazon (around $50)

Muse - no product has shipped as far as I can tell - currently taking pre-orders

Melon - another EEG headband, shipping Summer 2014

Bitalino - not for EEG, but is a set of physiological sensors for EMG, EDA, ECG along with a light sensor, an accelerometer and an LED. Can be split up into individual modules. Cost is $150 Euro.

Monday, August 12, 2013

I miss record stores

My son and I went to the local mall yesterday where a new FYE store had opened. While the selection is not great, it was just good enough that I noticed that one of my favorite bands, "Los Amigos Invisibles" had a new album. Actually, they have had 4 albums since I last paid attention.

While the internet is a great resource for finding music, being in a record store provides a much better experience for serendipity. I really miss record stores. I used to stop at the old Record Exchange at least twice per week. I loved their $1 bin. You can take a chance on a $1 CD like you would never would for a $15 CD. Some I bought because I liked the cover.

I need to make the effort to go down to Schoolkids records once/week and buy something there at least once/month, or pretty soon it won't be there.

Thursday, August 08, 2013

Switching from AT&T to T-Mobile

I recently switched my phone service from AT&T to T-Mobile. I did not have any particular problems with their service. Other than the typical crazy business practices that only mobile phone providers can get away with. I have 3 iPhone 4 devices on my account, and two of them are out of contract. Since T-Mobile has separated the phone subsidy from the service costs, I was able to reduce my phone bill from $190 to $90. This did involve paying the Early Termination Fee for one of the iPhones, which was $145. This was a no brainer as I can make back the savings in under 2 months.

I investigated the differences in coverage, and AT&T's 3G coverage is slightly better than T-Mobile's. Interestingly, T-Mobile's Edge (2G) coverage was slightly better than AT&T.

Having done this, There are other carriers (MVNOs) that will let you "bring your own phone", so your options are not limited to T-Mobile. Understand that these MVNO carriers use the infrastructure of AT&T and T-Mobile, so your coverage will not get any better than it would be with either of those carriers

I have some observations and suggestions for those that may want to consider changing carriers :

  • If you are planning to use unlocked phones, make sure you can get them unlocked. AT&T policy is that they will unlock iPhones that are out of contract with no outstanding charges (including ETF fees)
  • Carefully calculate your ETF liability. Payback is much longer if you have a substantial amount of contract remaining.
  • As contracts on your phones expire, get them unlocked, then test with a non-AT&T SIM to confirm the unlock
  • If you wish to keep your existing numbers, initiate the change process at the destination carrier. If you cancel service for your existing phone lines, the numbers will go back into the pool of available numbers
  • As for timing, I would switch less than a week before your billing date. This will minimize the time you will have to wait to close out your old account. If you will need to pay ETF fees, the unlock process may be delayed until the final bill was paid. I mistakenly switched a few days AFTER my billing date, and had the potential of having that third phone unusable for 3 weeks. Fortunately, AT&T was cooperative and performed the unlock once I called them to explain the situation. I did have to call them twice, but everything was very cordial.

So far so good. The only thing I miss so far is being able to forward emails to SMS. Setting this up in GMail involves typing in a confirmation code to verify that the destination address is valid. Unfortunately, T-Mobile's gateway cuts off the message after 160 characters and the confirmation code does not make it through.

Wednesday, July 31, 2013

Ubuntu does not remove old kernels

Ubuntu 12.10 does not do a good job of cleaning up old kernels. If you do a default install and allow Ubuntu to partition your disk, the /boot partition may fill up with no warning. Easy solution : install Ubuntu Tweak to clean out the old kernels.

Once installed :

  1. Run Tweak and click the "Janitor" button
  2. Click the checkbox next to "Old Kernel" under "System"
  3. Click the "Old Kernel" checkbox on the right, then the "Clean" button at the bottom right.

If you want to keep some of the old kernels, click the arrow next to "Old Kernel" checkbox, and they will be listed individually. You can then choose which to delete and which to keep.

Wednesday, April 24, 2013

Don't recycle electronics, repair them

Don't recycle, repair. My wife is now using two 20 inch Samsung LCD displays that I repaired with a well documented fix found on the internet. Spent about $4 in parts and an hour of my own labor. They were about a week away from being in the landfill. If your late model Samsung or Phillips LCD display/flat screen TV has recently stopped working (my Samsung LCD TV died about 4 years after its' purchase), it is probably easily fixed. --tom

Java is a 4 letter word

Got this today from a friend : Java users beware : Exploit circulating for just patched critical flaw So, Oracle just patched Java (again) and almost immediately that patch is being patched. If we were to sum up the cumulative misery (lost time, lost work, endless patching) that Java has inflicted on humanity, it would be a big number. The whole concept of "the same code runs everywhere" NEVER really worked. Whose time are we saving? --tom

Tuesday, March 26, 2013

I found an Optigan!

This past weekend, I found something from my musical "Holy Grail" list....an Optigan! The Optigan was built in the 1970's by Mattel Corp. (yes, that Mattel) in Compton, California (yes, that Compton). Wikipedia has a pretty good overview : http://en.wikipedia.org/wiki/Optigan The Optigan used samples recorded on circular film stock that looks like a vinyl LP, but you can see through it. Each key on the keyboard was mapped to a separate track on the optical disk. There were also tracks for the chord buttons and 5 special effects buttons. The Optigan was built by a toy company, thus the dodgy build quality. Some internal parts would disintegrate, the rubber idler wheel would get hard and the disk would slip. Nonetheless, the Optigan and its' low-tech sampling capablity has appeared in many commercial recordings (and still does to this day...check out the Optigan Facebook page). My main interest is historical. Here is my Picasa album of the teardown. When I brought it home and plugged it in, for the most part, it worked (this is unusual for Optigans). The special effects buttons were intermittent so I had to take off the top to access the buttons. To remove the top, the sides must be removed because they cover the screws that hold down the top. Yay. The pictures show the state of the internals. Not so bad. While reassembling, a small wire which moves the disk assembly fell out. In order to reinstall the part, I had to pry out an internal panel, replace the part (with forceps) and screw it back together. Another common problem is the idler wheel. The rubber has turned hard and slips on the disk. It can be resurfaced, but requires major disassembly to remove the part. Once I have a service manual (or at least a procedure), I may attempt this.

Thursday, March 07, 2013

Raspberry Pi, Puredata and MIDI

My initial test with the Raspberry Pi running Puredata did not go as well as I had hoped. Noticeable noise in the output audio. In my MUS306 class today, MIDI was the topic of discussion. Why not MIDI? Connected my $5 no name MIDI interface to the Pi and started Puredata. Changed the configuration to turn off the audio output and set the MIDI ports. Used my Yamaha QY-10 as the MIDI tone generator. Everything worked perfectly. Now I'd like to see if I can attach controls directly to the GPIO port. This would save me from having to attach another MIDI device.

Hammond Tone Generator - Part 3 - FInding the usable tonewheels

I have tested the outputs of the tone generator...there will be about 60 usable outputs. The other 31 outputs consist of the lower frequencies..the windings on the tonewheel cores include resistance wire which drops the levels significantly. I will have to further dismantle the TG to see if the resistance wire can be bypassed. I don't think that further dismantling is worth the potential of damaging the TG. I know that at least 2 or 3 of the tonewheels are stuck and will be looking at those to see if I can get them working. Fortunately, there appears to be a correlation between the color of the wire from the tonewheel and whether I am seeing usable output. For example, none of the red wires produce usable output. Most of the orange wires provide usable output. If I'm not getting output from an orange wire, something is probably stuck or broken. I have documented all the wire colors and whether I am seeing output. Next step is to recheck the outputs that should be working.

Sunday, January 06, 2013

Hammond Tone Generator - Part 2

I have tested all the outputs of the Hammond tone generator. Some of the levels are lower than others, but all are generating output. The levels are too low to be switched by anything other than physical switches, so they must be amplified. Many of the tone generator (TG) outputs are filtered through a LC filter to suppress harmonics and reinforce the fundamental. If I were to bypass this filter, I would have higher levels from each of the TG outputs. Unfortunately, the harmonics are clearly audible without the filter, so the filters must be retained. The lowest 42 tones have resistance wire wound into the coils, which is required when the TG outputs are connected to the various busbars in the organ, but not necessary if I were to replicate the Hammond wiring scheme (61 keys x 9 wires per key = 549 wires per manual). I plan to use the TG in a more novel way, which has yet to be determined. The TG output levels can be increased by moving the core closer to the tone wheel, but external amplification will probably be required.

Friday, January 04, 2013

The amazing Deacy amp

Was listening to Queen's Greatest Hits and was looking up the band members on the internet. Turns out the bassist, John Deacon, was an electrical engineer. In the early days of the band, he FOUND a amplifier circuit board on the street and decided to try and make it useful. He put the amp in a spare speaker cabinet and the Deacy amp was born. http://www.brianmay.com/brian/briannews/briannewsjun05.html In combination with May's Red Special guitar and a treble booster pedal, the classic Queen guitar sound was born. Expensive replicas have been built : http://www.astrings.co.uk/deacy_amp that achieve 85% of the sound. :-)

Wednesday, December 26, 2012

Hammond Tone Generator Project - Part 1

Early this year, I acquired a tonewheel generator (TWG) from a Hammond series H organ. The H series was rushed into production to compete with offerings from other organ companies, and suffered reliability problems as a result. Here are some photos :
The Tonewheel Chronicles
This TWG had already been removed from the organ and was headed for the dumpster when I picked it up. I have bolted it to a wooden frame to prevent flexing. The Hammond tonewheels organs were produced from 1935 until 1975. Tones were generated by spinning a toothed steel wheel next to an electromagnet. The wheels rotated at a fixed rate, locked to the speed of the synchronous motor. When operating properly, the TWG never went out of tune. This was an improvement over electronic oscillators, where at least 12 oscillators must be tuned to their appropriate pitches. Here is a more extensive description : http://en.wikipedia.org/wiki/Tonewheel So, what can you do with a TWG from a Hammond organ? First, I needed to test the TWG to make sure that it was operating properly.

Sunday, November 18, 2012

Synthesis on the Parallax Propeller

Have been experimenting with audio synthesis on the Parallax Propeller chip. The Propeller is a 8 core multiprocessor chip that can be purchased for $7. It is remarkably capable...the processors share the I/O bus on a time slice basis, so each processor knows when it has access to the I/O bus. Anyway... There is discussion on the forums about a SID Synth project. It runs an emulation of the Commodore 64 SID chip in 4 of the 8 cogs (processors). The processor accepts MIDI input and passes the note commands to the various cogs. Here is a link to the forum discussion : http://forums.parallax.com/showthread.php?133075-Polyphonic-SIDcog-synth-WIP Even more interesting, the circuit is capable of digital audio output via a simple RCA connector, using the S/PDIF protocol. I am using it with a $20 S/PDIF to Analog audio converter. I have the digital audio working, unfortunately not yet with the SID emulation. WIll be working on this. While this is nothing like having real SID chips, it is pretty impressive for what it can do.

Thursday, September 20, 2012

Microsoft Family Security. Useful? Not Really.

I'm trying out Microsoft Family Security on our Windows 7 box. Following is the list of software that my son is "using". Completely accurate, but pretty useless. There are 3 real programs in here : Google Chrome, Nero and Snagit Most of this stuff runs in the background all the time. Apparently there is no way to exclude this background nonsense from the report. I don't want to disallow it, because then everything breaks :

Citrix online plug-in Connection Center 4 hours 8 minutes

Event Monitor User Notification Tool 4 hours 8 minutes

Google Chrome 4 hours 8 minutes

HP QuickPlay Resident Program 4 hours 8 minutes

HPWAMain Module 4 hours 8 minutes

hpwuSchd Application 4 hours 8 minutes

Internet Low-Mic Utility Tool 4 hours 8 minutes

Saturday, June 02, 2012

Politics : Don't like the facts? Legislate them away

Our legislature in action : Climate change may be illegal So, if you don't like the science, make it illegal. This is the legislative equivalent of putting your fingers in your ears and saying "La La La, I can't hear you.

Wednesday, February 22, 2012

Project : Clavinova - where to go from here?

My attempt at repairing the Clavinova CVP-87A did not help (the audio output still sounds terrible), but there was a silver lining. It turns out that the MIDI out still works. I am currently using a Yamaha external MIDI sound module as the sound source. I disconnected the audio output of the mainboard, and connected the audio output of the MIDI module to the external input of the Clavinova. Unfortunately, there is no volume control of the external input -- the volume controls on the Clavinova do not work.

So, it is a perfectly good learning piano. I take my piano lessons on it. I love the way it plays. However, I can only control program changes. The first 10 are on their own buttons, the other 50 are available through more keystrokes. None of the other controls work, including the floppy disk interface. Every key has a corresponding LED, which is used to indicate the position of keyboard splits, among other things.

So my options are :

  • Purchase a new mainboard for about $500, which leaves me with a Clavinova and its' 1993 era voicings. Next year it will be 20 years old.
  • Do nothing and continue to use it as a piano controller with a bunch of non-functional controls. This is practical, but somehow dissapointing.
  • Replace the electronics with something more modern. I have looked at commercially available MIDI controllers. Almost none of them provide for velocity sensing and very few provide for control of 88 keys.

I have thought of building a computer inside the Clavinova. There is plenty of space. I could probably salvage the amplifier boards, but not much else.

Friday, February 17, 2012

Logitech Orbit AF - Only in Ubuntu :-)

Grabbed an old Logitech Orbit AF cam to do some video conferencing. Logitech does not support this device under Windows 7, and Mac OS X does not recognize it. Finally tried Ubuntu 11.10 and the camera WORKS, though the audio does not. Amusing.

Friday, February 10, 2012

It's been awhile : new HP laptop series naming?

It's been a while since I posted. HP has just come out with a new line of laptops -- The HP Spectre. Looked up the definition of spectre on the Free Dictionary : spectre US, specter [ˈspɛktə] n 1. (Spirituality, New Age, Astrology & Self-help / Alternative Belief Systems) a ghost; phantom; apparition 2. a mental image of something unpleasant or menacing the spectre of redundancy Hmmm.

Friday, November 18, 2011

Success : Auto update of Ubuntu 11.04 to 11.10

Did the "click the button" update from Ubuntu 11.04 to 11.10. Zero problems. I did have to ask Mr. Google how to get the old Gnome desktop back. This is the 2nd time I have done a hands off (mostly) Ubuntu upgrade...previously from 10.10 to 11.04. That upgrade was also flawless, but I did have to answer a few questions about keeping files that were to be replaced. I have been using Ubuntu as my primary desktop for the last 3 months, and have been very impressed. The biggest problem with using Ubuntu at NCSU is the problem with configuring the VPN. Which is totally a Cisco problem....their client assumes that Firefox is installed and tries to save the certificate in a .firefox directory. If that directory does not exist, the VPN client fails with a generic message. Why this dependency even exists is puzzling.

Thursday, November 17, 2011

Roland - Why such cheap connectors on expensive gear?

I just finished repairing the 2nd piece of Roland music gear in the past two months. Earlier, I removed the audio output jacks from a Roland SPD-S Sampling Pad and replaced them with a cable to an external breakout box. The 1/4 in output jacks are used more than any other connector on the device, but the parts are of poor quality, and mounted in such a way that guarantees their failure. No strain relief is provided -- all the stress of plugging and unplugging audio connectors is absorbed by the connector and its' solder joints. While the connectors are threaded for a mounting nut, the design does not allow them to be added. Original retail on this device was between $500 and $800. Earlier this week, I repaired a Roland RD-700SX Stage Piano. Original retail was likely between $1000 and $2000. The contacts of the power connector were totally mangled. Rather than use a replacement part that would likely fail again, I used a connector from an old piece of test gear.