Building sensors for the Scratch programming language

[Kevin Osborn] is making it a bit easier for young programmers to write programs that interact with the physical world. The device he’s holding in the picture is an Arduino based accelerometer and distance sensor meant for the Scratch language.

Scratch is a programming language developed at MIT. It has kids in mind, and focuses on graphical building blocks. This can make it quite a bit easier to introduce youngsters to programming concepts without the roadblocks and gotchas that come with learning syntax.

As you can see in the clip after the break, [Kevin’s] Arduino sketch includes hooks that automatically pull the accelerometer and distance data into the Scratch environment. We figure his example provides everything you need to get just about any type of sensor up and running, be it a magnetometer or LDR (both of which would make a nice burglar-alarm type project). Give it a try with your own hardware and see what you can accomplish.

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Retrotechtacular: The Blit has given me access to the power of multiprogramming!

We normally try to be descriptive with our titles. But when that statement pops out of the narration with notable excitement it made us chuckle. This installment of Retrotechtacular is a promotional video for the Blit. It’s a graphics-based hardware terminal for Unix systems. It’s biggest boast is the ability to run (and display on screen) several different programs at once — an activity called multiprogramming. But there is also the “digitizing mouse”. On board is a 68000 microcprocessor 256k of RAM (they call it a quarter meg), and connects via RS232. The screen is 800 by 1024; that’s right, it’s a portrait orientation.

Notable in this episode are some classic eyeglass frames, and rad synthesizer sounds for scene transitions. Whatever happened to videography technique that uses a dimwitted companion to ask that all-knowing narrator stupid questions?

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Want to play Pong on your Oscilloscope?

I always have! I don’t know why, but I like the idea of using an oscilloscope screen as a general use video display. Why not? In my case it sits on my desk full time, has a large screen area, can do multiple modes of display, and is very easy control.
Making an oscilloscope screen do your bidding is an old trick. There are numerous examples out there. Its not a finished project yet, so be nice. It is actually rather crude, using a couple parts I had on hand just on a whim. The code is a nice mixture of ArduincoreGCCish (I am sorry, still learning), and includes the following demos:

  1. Simple low resolution dot drawing
  2. A font example
  3. A very quickly and badly written demo of pong

The software runs on an Attiny84 micro controller clocked at 16Mhz, paired up with a Microchip MCP42100 dual 100k 8 bit digital potentiometer though the Attiny’s USI (Universal Serial Interface) pins. This is a fast, stable and accurate arrangement, but it requires sending 16 bits every time you want to change the value of one of the potentiometers so its also very piggy. I was just out to have some fun and did not have a proper 8 bit DAC. This was the closest thing outside of building one.
Join us after the break for pictures a (very) brief video and more.

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Displaying graphics on an oscilloscope

[Andrew Rossignol] was curious one day and decided that he wanted to display graphics on an oscilloscope after playing around with the X and Y inputs.

[Andrew] started out with a resistor ladder on the DAC of his AVR Butterfly. He was able to to draw a line on the oscilloscope’s screen but bandwidth limitations forced him to reconsider his approach. A friend wrote a Python script to generate C code so the ports of the Butterfly can be toggled. After getting the Butterfly to generate a voltage for every non-white pixel, [Andrew] was impressed with the results so the code was modified determine the brightness of each pixel. The setup managed 10 shades of gray and careful selection of what graphics to post on the build log assured the project a little bit of blog cred.

There are a few ways to display a picture on an oscilloscope, like plugging the Hsync and Vsync into the inputs of a scope. Except for a few music visualizations, we haven’t seen a scope display generated from a microcontroller. Great work [Andrew], but we’d like to mention there’s a grayscale Hack a Day logo from way back when.

Check out a video of [Andrew]’s oscilloscope after the break.

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Spy Video TRAKR: software and first hack

Our initial view of the Spy Video TRAKR “App BUILDR” site had us believing this would be an internet-based code editor and compiler, similar to the mbed microcontroller development tools. Delving deeper into the available resources, we’re not entirely sure that’s an accurate assessment — TRAKR may well permit or even require offline development after all. Regardless of the final plan, in the interim we have sniffed out the early documentation, libraries and standalone C compiler and have beaten it into submission for your entertainment, in order to produce our first TRAKR hack!

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Behind the scenes of a 1K graphics demo

Programmer/designer [Steven Wittens] has posted a fantastic write-up on the black art of producing compact demo code, dissecting his own entry in the 1K JavaScript Demo Contest. The goal is to produce the best JavaScript demo that can be expressed in 1024 characters or less and works reliably across all standards-compliant web browsers.

[Wittens] details several techniques for creating a lot of visual flash in very few bytes, including the use of procedural graphics rather than fixed datasets, exploiting prime numbers to avoid obvious repetitions in movement, and strategically fudging formulas to save space while adding visual interest. These methods are just as applicable to other memory-constrained situations, not just JavaScript — some of the contest entries bear a resemblance to the compact microcontroller demos we’ve previously showcased, except running in your browser window.

The contest runs through September 10th, allowing ample time to come up with something even more clever. Whether he wins or not, we think [Steven] deserves special merit on account of having one of the most stylish blogs in recent memory!

Art From Code: Generative Graphics

[Keith Peters]’ blog Art From Code is devoted to his beautiful graphics from computer source code, also known as generative art. Although [Peters] is reluctant to reveal his source code, algorithmic graphics can be created with the help of tools like ActionScript, Flash, and Flex. There are some great tutorials that can start you on the path to making your own evocative art.

[via Neatorama]