DorkbotPDX people doing strange things with electricity

Jim Larson and I are doing an informal intro to Arduino programming class
at CSE at 7-9 PM on Tuesday May 14.

We'll be going over some simple programming basics like BLINK, Buttons,
Stepper Motor Controls, Serial Communication. Depending on the class we may
tailor the subjects to the individuals' projects being considered.

Be aware that that is Memorial Day weekend. Some of you may be out of town
with family that weekend.

Truly,

Mark Allyn
Portland, Oregon
[link]
971-563-7588

Hey Dorkbotters,

Darren Kitchen of Hak5.org is doing a nationwide travel tour thing. He's
scheduled to come into Portland May 25th and 26th (Saturday and Sunday). It
doesn't look like he has a venue yet.

It's our off week that weekend, but I imagine a number of people here would
be interested in whatever he's up to/doing/whatever.

A few people last night asked about the video to LEDs code running on
the Beaglebone Black.

Here it is:

[link]

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I have a contact at Alfa in Taiwan who, for some reason, asked me about
putting together a better datasheet for a WiFi access point they sell.
(AFAIK, it's a cheap Atheros AP running OpenWRT...at any rate, that's
their product that I've used happily and successfully in the past.)

Does anybody here do that kind of thing, and need extra work? I'd like

Hello Fellow Dorkbotters,

A while back I ended up sorting through a lot of my old stuff and will be
bringing it tomorrow for the Free parts/stuff table/speaker.

Among those things:

- A canon powershot S400 (digital elph) including battery, charger, and
case. The battery doesn't hold a charge, but AFAIK the camera still works

I'm bringing the 1920 LED display to Dorkbot tomorrow.

The code now plays live video from a webcam with animated GIF overlays,
triggered by DDR-like stomp pads.

So far I only have a couple GIFs created. If you'd like to animate
LEDs, please bring a 60x32 animated GIF file to the meetup!

The Gluion is an OSC sensor interface device based on the Altera Cyclone I
FPGA. I bought a pre-release version in 2004 to use with Max/MSP for video
installation control. it was a somewhat buggy beta product back then.
Since the Arduino came out I've never really used it for much. I'll bring

Ironically, solder sucking/wick can make it worse, since it will remove
most, but not ALL the solder. At that point, you wind up with the mimimum
amount of solder necessary to hold things together, and no easy way to get
at it with an iron. Sometimes it pays to have a lot of solder, so it
retains enough heat to stay molten while you pull connectors/wires out.

Best tool I've found is the desoldering iron from radio shack, especially
when modified with a small vacuum hose. Unfortunately, I took apart the
vacuum attachment for another project, but there is a stock desoldering
iron down at BrainSilo - stop by Thursday night during open house and try
it out. Or just buy one, they aren't expensive - and it works

I have a metcal desoldering station. my guess is you are running into RoHS solder which melts at as higher temp and is much harder to desolder. You might try diluting the rohs solder with normal solder to reduce its melting temp. Basically just add normal solder to the joint after you get rid of as much rohs solder as you can. Then you might have better luck with the solder sucker.

Getting things ready for the DorkbotPDX exhibit at Maker Faire.....

This blog entry is sort-of placeholder page, to be updated with photos and more info during or shorly after Maker Faire.

Click "Read more" for more pictures, source code and other stuff.

I originally published the OctoWS2811 library in February with an example that plays video using a program written in the Processing environment.

For this project, I decided to attempt streaming live video and also overlaying animated GIF images triggered by user input.  Originally I had planned to use Processing again, but with the Beaglebone Black was released, I couldn't resist the opportunity to make it run on such a tiny little Linux board.

Here's a block diagram of the system.  It's from the printed handout (PDF in the files below) I'll have for people at Maker Faire.

The Beaglebone runs this project easily, using about 30% CPU while the video is streaming and GIF files are triggered.  I used the efficient video4linux API, via the v4l2 library (which is installed by default on Beaglebone's Angstrom Linux distribution).

I also used libudev to detect the attach and remove events for the webcam and the USB virtual serial devices from the Teensy boards.  Each board implements a very simple identification query/response, so when udev detects each serial device, it sends the query and parses the response.  This completely avoids hard-coding any device names.  The complete source code is available below, for anyone who wants to use this technique.

Not all has been perfect with Beaglebone.  The main problem has been its poor detection of USB devices connected to its host port.  This post about a musb bug was the best info I found.

Leave your usb hub connected with at-least one device plugged in at
ALL times from the moment you powered it up..

However, this wasn't the only issue.  The Beaglebone Black just can't see some hubs reliably.  Here you can see a bracket I built for a smaller hub which works great on 2 PCs and 1 Mac I tested, but the Beaglebone Black almost never detects it (as if nothing were plugged into its host port).  But it can use this somewhat-larger hub (so now I need to make an bigger mounting bracket).  I'm hopeful future Beaglebones will ship with this problem fixed, but it is something to consider for anyone attempting these sorts of projects using the USB host port.

I should mention I also tried using a Raspberry Pi.  The uvcvideo driver (for the webcam) exists and works on the Pi, but it drops most of the frames.  The resulting frame rate is only a few per second.  It's utterly unusable.  I found numerous threads where people had similar issues on the Pi, without solutions, other than anticipating the native camera.  I found discussions saying some older versions might have a better driver, but I tried several and all were terrible.

On Beaglebone, this Logitech 9000 webcam works great with uvcvideo.  The default Angstrom Linux doesn't have the driver, but it's a simple matter to add it with "opkg install kernel-module-uvcvideo_2.6.39-r102o.9_beagleboard.ipk".  I found this on their website, and I'll attach the file to this message, just in case.

The LEDs are the same 1920 array (60 by 32) I used previously for developing OctoWS2811.  I cut them out of the rubber tubing, because they run pretty hot for indoor use inside those tubes.

Of the 1920 LEDs I purchased from Ray Wu on Aliexpress, 5 have died.  Originally it was only 1 dead pixel and 2 more that would stop working after an hour or two of use.  Here you can see one of the LEDs which was replaced.  I hoping no more die at Maker Faire, but if they do I'll be prepared to cut them out and solder in repacement.

Here are the stomp sensors.  They're just Piezeoelectric speakers, Murata 7BB-27-4L0, taped and glued to cardboard and placed under Soft Tiles foam mat material.

The sensors are connected to an interface board that converts the analog voltage to digital signals using LMV393 voltage comparators.  The Arduino attachInterrupt() function is used to respond to the rising edges.  Teensy 3.0 supports attachInterrupt on all digital pins, so it's easy to connect lots of sensors to just 1 board.  There's a brief timeout after sending any output where additional triggers are ignored.  That helps prevent vibration from triggering the nearby pads.  The complete source code is available below in the attached files.

 

That's about it for now.  I have a long list of stuff to do before hitting the road tomorrow for San Mateo (including making a new bracket for the BB+Hub).  But the project is working pretty well.... well enough I can spend a bit of time updating this blog.

More photos and video ought to appear here as people play with it over the weekend......

AttachmentSize mf2013_handout.pdf89.3 KB ledvideo_06.zip33.3 KB beaglebone_uvcvideo.zip35.67 KB stomp_pads_sketch.zip1.18 KB

The input select switch on my amp needs to be replaced. I spent a great
deal of time with a solder sucker and wick in an attempt to do it myself.
Now I need an expert to finish the job.

If you know anyone, please let me know.

Thanks,

Ken

No fuss. I'll see if they wind up on my rounds today.
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I pick up a number of them at gizmos a couple weekends ago. I'd guess they still have some. I'm pretty sure they were smt style. I can take a picture later if you want.

-c

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Yay! You are a hero. Though since DX wants $2.50 for 20, I might also get
some to add to the parts bin later. If I need one, I'm sure others do too.

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I have 2 in a small pile of parts I was going to add to the free parts
box next Monday.

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So before I order a mess of 'em from Hong Kong, does anyone around here
have ordinary micro-USB sockets for sale or barter?
I need to replace the one in my phone.

Also, FreeGeek has a handful of SMT jellybeans and suchlike these days.

Thanks,
Aaron
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Hello all,

Pardon the intrusions but PLUG is having a non-technical presentation
and discussion about confronting depression in the tech community.

Feel free to pass this on as you see fit.

Portland Linux/Unix Group Meeting Announcement

Who: Yshai Boussi
What: Confronting Depression

Eric-

Landsberg is Wilsonville may have what you're looking for. I have worked
with these guys to cut foam before for tool boxes. They use one of these
machines: [link]

I would say as long as you have a CAD or 2D drawing of the cuts, they
should be able to do it for you.