How To Build OpenOCD With Stellaris Launchpad Support

November 19, 2012 by Mike Szczys 11 Comments

The stable version of OpenOCD (an open source On-Chip Debugging software package) doesn’t have support for the ICDI protocol used by the Stellaris Launchpad board. But it is pretty easy to build your own OpenOCD from source after patching it to use the protocol.

We’ve already seen an open source tool used to flash binary images to the TI ARM board. But that can’t be used with GDB. With the recent inclusion of USB-based ICDI in the OpenOCD development branches we gain all the features that come with the package. We’re quite happy hear about this as we use OpenOCD for many hardware architectures and this makes development for this board feel more like normal.

Our Stellaris Launchpad hasn’t just been sitting in the closet since we got it. We’ve learned a lot by using the lm4tools to program the chip as we work our way through the online workshop. We’re really beginning to like the Stellarisware peripheral library that has been provided. For us it works in a much more intuitive way than the one that STM uses with their ARM Discovery boards. We’d recommend taking a look at the workbook PDF (which is basically a verbose listing of what’s in the video series) and the library reference (called SW-DRL-UG-9453.pdf) which is in the docs folder of the Stellarisware package.

[via Dangerous Protoypes]

Large Area X-ray Detector

November 16, 2012 by Mike Szczys 17 Comments

This is an x-ray detector built by [Ben Krasnow]. It’s an interesting combination of parts working with an oscilloscope. The result is an audible clicking much the same as you would hear from a Geiger counter

He’s measuring backscatter, which is the reflection of x-rays on other objects. Because the signal will be quite weak compared to waves emitted directly from an x-ray source he needed a large collector to measure them. He started by gutting an x-ray image intensifying cassette. This has a phosphor layer that glows when excited by x-rays. The idea is that the glowing phosphors do a better job of exposing film than direct x-rays can. But [Ben’s] not using film. He built that pyramid-shaped collector with the phosphor material as the base. At the apex of the pyramid he mounted a photomultiplier tube (repurposed from his scanning electron microscope) which can detect the excited points on its surface. His oscilloscope monitors the PMT, then issues a voltage spike on the calibration connector which is being fed to an audio amplifier. Don’t miss his presentation embedded after the break.

[Ben] mentions that this build is in preparation for a future project. We’d love to hear what you think he’s working on. Leave your guess in the comments section.

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Python Script Lets You Monitor Multiple Serial Devices At Once

November 16, 2012 by Mike Szczys 17 Comments

Not knowing what’s going on inside of your electronics projects can make it quite difficult to get the bugs out. [John] was bumping up against this problem when working on wireless communications between several devices. At just about the same time his friend came up with a script with lets you monitor multiple serial devices in one terminal window.

We’re used to using minicom, a Linux package that does the job when working with serial connections of all kinds. But [John] is right, we’re pretty sure you can only connect to one device per minicom instance. But [Jim’s] Python serial terminal (available in this git repository) allows you to specify multiple devices as command line arguments. You can even use wildcards to monitor every USB connection. The script then automatically chooses a different color for each device.

The image above is from [John’s] wireless project. Even without any other background this shows how easy it is to debug this way rather than tab back and forth between windows which gets confusing very quickly.

POV Wheels For A Longboard

November 16, 2012 by Mike Szczys 9 Comments

If you don’t mind working with really small components this POV wheel project for a longboard will certainly attract some attention.

The name of the game here is small and cheap. Small because the wheels are only 72mm in diameter (about 2.8 inches). Cheap because [Ch00f] wants to produce and sell them locally. He went with an ATtiny24 microcontroller driving fifteen LEDs. Obviously this will present a problem as the uC uses a 14-pin SOIC package and that’s just not enough I/O to drive the LEDs individually. Add to that the issue of storing patterns to be displayed and you start to run out of program memory very quickly.

But obvious he pulled it off. The image above shows the wheel displaying the CT logo (for ch00ftech.com) and there are several other patterns shown off in the clip after the break. The LEDs are multiplexed, but the wheel spins fast enough that this turns out to be okay. The rotation is measured by an IR reflectance sensor aimed at the stationary axle. A CR2032 powers the device, with some counterweights added to keep the wheel balanced.

Our only concern is the fragility of the exposed electronics. But if you hit the right BOM price we guess you can just replace the board as needed.

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Raspberry Pi Driven Polargraph Exhibits High Precision Drawing Ability

November 16, 2012 by Mike Szczys 23 Comments

This polar graph draws some amazing shapes on a dry erase board. Part of that is due to the mounting brackets used for the two stepper motors and the stylus. But credit is also due for the code which takes velocity into account in order to plan for the next set of movements.

The Go language is used to translate data into step commands for the two motors. This stream of commands is fed over a serial connection between the RPi board and an Arduino. The Arduino simply pushes the steps to the motor controllers. The inclusion of the RPi provides the horsepower needed to make such smooth designs. This is explained in the second half of [Brandon Green’s] post. The technique uses constant acceleration, speed, and deceleration for most cases which prevents any kind of oscillation in the hanging stylus. But there are also contingencies used when there is not enough room to accelerate or decelerate smoothly.

You can catch a very short clip of the hardware drawing a tight spiral in the video embedded after the break.

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AVR Minecraft Server Lets You Toggle Pins From The Virtual World

November 16, 2012 by Mike Szczys 21 Comments

Wanting to test his skills by building a webserver [Cnlohr] decided to also code a Minecraft server which allows him to toggle pins from inside the game. The rows of switches seen above give him direct access to the direction register and I/O pins of one port of the ATmega328.

The server hardware is shown in the image above. It’s hard to tell just from that image, but it’s actually a glass substrate which is [Cnlohr’s] specialty. He uses an ENC424J600 to handle the networking side of things. This chip costs almost twice as much as the microcontroller next to it. But even in single quantities the BOM came in at under $20 for the entire build.

In the video after the break [Cnlohr] and a friend demonstrate the ability for multiple users to log into the Minecraft world. The simulation is fairly bare-bones, but the ability to affect hardware from the game world is more exciting than just pushing 1s and 0s through some twisted pairs.

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Hackaday Links: November 15, 2012

November 15, 2012 by Mike Szczys 14 Comments

Another way to break out dual pin headers

[Uwe] wrote in to share his technique for breaking out dual pin headers. He uses two single pin headers, a piece of protoboard, and a dual row pin socket to make an adapter. This is removable where the other method we saw this week was not.

Web-based slide show hack

Wanting to use an old Android tablet as a digital picture frame, [Gordon] coded up a simple way to use an HTML page to scan your picture directories to feed a rotating background image.

The simplest hot plate

For his chemistry experiments [Charlie] is using a plain old clothes iron for a hot plate. he simply clamps it upside down to the bench. It doesn’t have any stirring abilities, but we already have an old iron in the shop which we use for toner transfer so we’ll have to keep this in mind if we ever need to heat chemicals (might be a good way to warm etchant).

A charging VU meter

This Cambrionix series8 universal charger has columns of LEDs that are animated when a device is charging. [Steve Tyson] works for the company and has had some fun messing with the firmware. He’s showing off the display as a VU meter.

Game Boy knockoff teardown

This wide-form-factor Game Boy is a knockoff from way back when the original system hit the market. You won’t want to miss this lengthy post that takes a look at what’s inside. [Thanks Neil]