If You Own A Camera You Need To Try Light Graffiti

November 22, 2013 by 24 Comments

Do you have a camera that’s capable of controlling how long of an exposure it takes?  With this and any small light source, you can make a really awesome illuminated image like the one featured above.  Combine this with the hacking skills that you’ve hopefully learned from reading Hackaday, and the visual possibilities are endless.

Let’s look at the background of this entertaining light hacking technique, and how you can make images like this yourself!

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Learn Engineering And Draw Narwhals

November 22, 2013 by 23 Comments

narwhals

Using LEGO robots and other ‘intro to robotics’ platforms is a great introduction to kinematics and programming, but if you’re teaching a classroom of people who don’t know what a 1/4-20 screw is, perhaps it’s not the right introduction to engineering. That’s the thinking behind NarwhalEdu’s upcoming, Kickstarted online course: give kids a bunch of servos, bolts, and a microcontroller, and they’ll be able to build anything, and not just what the instructions for a Mindstorm’s robot says.

Robots, Drawing, and Engineering is an online course built around a simple SCARA arm robot. It’s made out of laser cut hardboard and powered by three servos and an Arduino Nano with an extension shield. After building this robot in the first hour of the online class, students then learn a little programming and get their robot drawing everything from narwhals to nyan cats and faces.

In the second part of the course, students then tear apart their robot kit and start making other, cooler interesting devices. There’s a contest for the coolest project that will hopefully go a long way to show how creative engineering can be.

Two videos below of the NarwhalEdu SCARA arm in action.

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Building A Crystal Clear Whiteboard

November 22, 2013 by 77 Comments

[Michael Peshkin] teaches mechanical engineering at Northwestern University. He likes to use diagrams to illustrate his point, but he also likes to face his students when doing so. His solution was to develop this clear whiteboard which ends up unlocking a lot more than just some hand-drawn schematics.

It’s a bit hard to see what he’s written on the board in the image above but squint and see if you can figure out what’s wrong with this style of teaching? Everything he’s writing is backwards. That’s not actually a problem in this case as [Michael] uses flip teaching. He records and posts all of his lectures online. Classroom time is then used for question and answer on the lecture subjects. In order to get the text to read the correct way he just bounces the camera off of a mirror.

The board itself is a huge sheet of tempered glass attached to the metal frame using bolts through holes in the pane. This leave the edges free. He added extruded rail to the top and bottom to embed strips of LEDs. They light the inside of the glass, and excite the fluorescent dry erase marker ink making it much more visible. [Michael] didn’t stop with the board, he  also rigged up a lighting system that gives him a lot of options, and uses a monitor for dealing with digital overlays. He can put up a diagram on the computer, watching the monitor to see where his marker is making annotations. All this happens in real-time which means no post production! See a demo of these features after the break.

This could all be done without the glass at all, but that would make it quite a bit more difficult for the person doing the writing.

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Using DMA To Drive WS2812 LED Pixels

November 22, 2013 by 17 Comments

It’s pretty well known by now that the LED pixel hardware which is starting to be commonplace, both WS2811 and WS2812, needs pretty strict timing in order to address them. There are libraries out there which mean almost no work on your part, but that’s no fun. [Elia] started looking into what it takes to drive the hardware, trying out a few 8-bit micros before moving to 32-bit with the help of an STM32VL Discovery Board. The move to a beefier processor brings a lot of speed, but why bit bang everything? He came up with a way to use the PWM and DMA features of the chip to drive the LEDs.

DMA is the Direct Memory Access unit that allows you to change the values being sent to the pixel without interrupting the processor. This is done by pre-loading the data at a memory location. This buffer is automatically read by the DMA unit — its values are used to set the PWM timer compare trigger in order to send out logic values show in the diagram above.

If you do want to delve further into this topic here’s a collection of techniques for driving the WS2811.

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Tricky Repair Of Power Driver For CNC Machine

November 22, 2013 by 24 Comments

tricky-power-driver-repair

Designing and building something from scratch is one thing. But repairing fried electronics is a much different type of dark art. This video from [Mike’s Electric Stuff] is from more than a year ago, but we didn’t think you’d mind since what he accomplishes in it is so impressive. He’s got a burnt out pick and place hybrid power module which isn’t going to fix itself.

The power module construction includes a part that has chip-on-board-style MOSFETs and the circuitry that goes with them enclosed in a black plastic housing. It’s kind of like a submodule was encapsulated using the same plastic as integrated circuits. After cracking it open it appears the bonding wire has burnt away. [Mike] connects a jumper wire to one of the board traces in order to use an external MOSFET. This is much easier said than done since the module substrate is ceramic designed to dissipate heat. We’re amused by his technique of melting the jumper into the plastic housing to protect it from the heat sink that goes over the package. In the end he gets his CNC running again. This may not be the best long-term fix but he just needed to continue running until a proper replacement part arrives.

Oh, one more thing: the Metcal vacuum desolderer he uses in the video… do want!

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A Low-Cost Modular High Altitude Balloon Tracker With Mesh Networked Sensors

November 21, 2013 by 2 Comments

[Ethan] just tipped us about a project he and a few colleagues worked on last year for their senior design project. It’s a low-cost open hardware/software high altitude balloon tracker with sensors that form a mesh network with a master node. The latter (shown above) includes an ATmega644, an onboard GPS module (NEO-6M), a micro SD card slot, a 300mW APRS (144.39MHz) transmitter and finally headers to plug an XBee radio. This platform is therefore in charge of getting wireless data from the slave platforms, storing it in the uSD card while transmitting the balloon position via APRS along with other data. It’s interesting to note that to keep the design low-cost, they chose a relatively cheap analog radio module ($~40) and hacked together AFSK modulation of their output signal with hardware PWM outputs and a sine-wave lookup table.

The slave nodes are composed of ‘slave motherboards’ on which can be plugged several daughter-boards: geiger counters, atmospheric sensors, camera control/accelerometer boards. If you want to build your own system, be sure to check out this page which includes all the necessary instructions and resources.

Making The Worst Linux PC Useful

November 21, 2013 by 16 Comments

AVR

After seeing [Dimitry] build the most minimal Linux computer ever, [Kyle] decided he needed one for himself. In true hacker fashion, he decided to take this build for the worst Linux PC one step further: he would add I2C to his version, making it somewhat useful, considering the number of I2C peripherals out there.

This build is based on [Dmitry]’s ARM Linux computer emulated on an 8-bit AVR. It’s a full-blown Linux computer with 16 MB of RAM courtesy of a 30-pin SIMM, a lot of storage provided by an SD card, all running on an emulated ARM processor inside a lowly ATMega1284p. [Kyle] built this clone over the course of a few months, but from the outset decided he wanted to implement an I2C protocol on this terribly under specced computer.

After booting his computer, [Kyle] eventually got an I2C module loaded by the kernel. With an I2C module and a few spare GPIO pins, he set out to create something to attach to this terribly slow computer – an ancient LED dot matrix display. With a real-time clock, this display became a clock  with the help of a homebrew program written in C. Considering the speed of the emulated processor, the program takes nearly three seconds to read the RTC and display the current time to the display. We’re thinking it was a wise choice to only implement hours and minutes in this clock.

If having a useful computer running at about 10 kilohertz isn’t enough, [Kyle] also compiled the classic text-based adventure Zork. It actually runs, proving you don’t need Megahertz of power to do something useful and fun.