Monthly Archives: November 2015

Not Original, But, Still Kind of Cool…

To make a long story short, I ended up at one point, buying two little 3x3x3 LED cubes from Radio Shack. They were about $20 a piece. Ultimately, the point was to mount them on my Udoo Quads (http://www.udoo.org) and control them through the Serial comms port using a Python script. While I had some trouble porting over the code from the Arduino it was meant to run on, once I figured out what I was missing it was a snap.

I even asked Dave to look at it, he couldn’t figure it out either, the answer came to me in a flash of insight. The cube is a Charlieplex system, and I was confused about the order in which the pins controlling the LEDs were being set high and low. To both of us at the time, it made sense, setting them high, turns the LED’s on, setting the pins low would turn them off.

Turns out it was the opposite. What we both missed was that, when the pins are low, they are grounded. Thus, if you are putting in 5v at each end, you get nothing, ground the cathode end and the power flows…. and we both  missed that part, that the cathode was set high to “shut off” the LED’s.

Anyhow, I kept one of the cubes for other purposes. I wanted a cube in a different color so I sourced almost all the parts from eBay and assembled one from scratch in Blue 3mm LEDs with an Arduino prototyping shield. See the video below for the Cubes in action.

Aside from having a cool little 3x3x3 LED cube, I had a purpose for controlling them with the Udoo’s. At the moment, I use the Udoo’s mostly for experiments, while they are not doing anything in particular, they are running Litecoin crypto coin mining software. They really aren’t powerful enough to make any Litecoin worth having, BUT, when the mining software submits a hash, it takes the cube out of demo mode (cycling through all the patterns it has except for one special one) and then display’s the special one. Basically when a hash is submitted, the cube pulses itself.

The two Udoo’s the cubes are on, will never find a block or get much in the way of work hashes, but it is a neat conversation piece.

Holiday Cheer

I worked on this project last year. Electronics by me, wreath’s by my wife. We made two of them. We also make a pretty good team. Most of the parts by Adafruit… ahaha…

eWreath

eWreath with the LED’s off

Of course, it looks better with the lights on…

eWreath with the lights on

eWreath with the lights on

Basically, its a typical wire wreath (from Joann’s) with some extra wide gift ribbon hot-glued and wired up to the wreath wire. Inside is a strip of Adafruit Neopixels also wired up to the frame.

The Neopixels are driven by an Adafruit Trinket mounted in a project case. The colors can be programmed in code and they cycle. I was heading towards a more ambitious configuration where I’d use something that had WiFi or Bluetooth, so I could control it from a cell phone or tablet. I am saving that for Version 2. I’d upload a video, but the best one I have is larger then the max limit for uploading videos here. 🙁

The colors can be changed to suit the holiday since the Neopixel strip is RGB and you can program most colors. Next year we might put it out during Halloween with a nice Orange glow.

And that is one of the more interesting things. The Neopixels are quite bright. Seen the picture above, the brightness and color was turned down a bit because in full red it washed out the picture. I was hoping the ribbon would diffuse the LED’s… and it did somewhat, but the Neopixels are REALLY bright.

 

 

Forgive the rapid fire posts…

I took my independent blog offline… more or less, actually, GoDaddy took it offline… I had… technically… made the mistake of selecting a Windows environment for my hosted content. GoDaddy eventually turned over the Windows based hosting to Plesk. But even so, that was only for a year at the current rate I pay. After that, who knows.

So I set the Plesk stuff up… I wasn’t happy with it… I let the blog and site lapse as they turned it off. I saved the content, hoping to deploy it someplace else… I will eventually do that… but I kind of got distracted with other projects.

Of course, I skulk around the Element14.com community looking for pointers, tips and occasionally… parts for my electronics hobby.

Periodically they have these things called “Test Drives”. Basically you submit an application about what you plan on doing with the thing/stuff they are test driving and if you are chosen, then you get one of the things/stuff’s to test drive and do a write up. I was fortunate to have been selected for a Raspberry Pi 2 test drive; which was quite awesome. I wasn’t completely happy with the test drive though because I ran into some minor problems along the way with software, BUT, thankfully I learned a thing or two in the process. For example, I wanted to run performance tests on it. While I did that, I ran into a dead end at the Linpack series.

However, this lead me to another test suite, that I use regularly now for testing these little small board computers.

Today, I discovered they have another road test. This time with what looks like an introductory course in Microcontrollers and C. Of course, one of the things you have to do in the application is list some of your projects… with my personal blog offline… that kind of messes me up a bit with links to project content… so I am posting them here in rapid fire progression so I have a place to link to them for the application.

While I think I am probably a good candidate for the “microcontroller” part of the course material, the “C” part, not so much. While I certainly could use a refresher, my experience with… a number of more recent languages (C#, Java, JavaScript), which are descended from C/C++… and the fact I already know C and C++, kind of makes that part mostly just review material for me.

Although, I believe C with Microcontrollers, is not exactly like C as an application language… there might be some surprises there for me. At one point I tried using some “C” trickery on an Arduino and… well… it didn’t go so well… for some reason Arduino’s aren’t so good at handling dynamic array’s using “calloc” or the more C++ like “new” statement.

Anyhow, should be interesting if my application is accepted. Otherwise, back to the O’Reilly books for me.