Restarting 3D Prints

Image of a 3D print which was restarted using a different material

If a 3D printer is interrupted during a print, it will usually result in a junk part. Resuming the print can be very difficult. A group of researchers at MIT have built an add-on for 3D printers that uses a laser scanner to evaluate the state of the print, and allows the printer to restart.

While this will allow you to salvage some partially competed prints, the interesting application is switching between materials. In the image above, the lower piece was printed in ABS. The print was interrupted to change materials, and the top cube was printed in PLA. This allows for prints to mix materials and colors.

The add-on was tested with the Solidoodle 3D printer, and can be built for about $60. It requires a laser mounted to the print head, and a low-cost webcam for performing the measurements. While the group will not be continuing work on this project, they plan to open source their work so others can continue where they’ve left off.

After the break, we have a video of the printer performing a scan and resuming a print.

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Raspi Ambilight Integrated In A 19″ Rack Packs Lots Of Peripherals

raspi ambilight

Ambilight systems create light effects around your monitor that correspond to the video content you’re playing. [Sébastien] just build his (French translated to English, original here) and embedded all the elements in a 19 inch rack he bought from Farnell.

As most ambilight systems we’ve covered over the years the HDMI signal is first split in two, one being sent to his monitor while the other is converted into a S-Video signal. The latter is then captured with a STK1160 stick connected to a Raspberry Pi. A python script using the OpenCV library is in charge of extracting the frames pixels and figuring out what colors should be sent to the SPI connected LPD8806 LEDs. A nice web interface also allows to drive the LEDs from any platform connected to his local network. Finally, a standard HD44780 LCD and an infrared receiver are connected to the raspberry, allowing [Sébastien] to control and monitor his platform. Funny thing: he also had to use two relays to power cycle his HDMI splitter and converter as they often crash. You can check out a demonstration video from a previous revision after the break.

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Makers’ Mountain House Promises Productivity Without Distraction

Maker's Mountain House Retreat

Ever wish you could take your projects with you on vacation? Do you ever take time off from your job just to work on things at home? What if you could combine an actual vacation retreat, with the thing you love most — making? A group of people are starting to plan the Maker’s Mountain House, and it sounds pretty interesting!

Makers Mountain House will be a  mountain retreat and makerspace, whose purpose is to provide time and space for makers to create. Makers Mountain House will be open to the public June through October, and reserved exclusively for makers and artists, November through May.

It’s still completely in the planning stages, but the organizers sound pretty serious about making it a reality. It’s planned for somewhere in Upstate New York (unconfirmed) – so if you’re interested in something like this, do them a favor and fill out the quick survey they’ve posted.

And no – just in case you’re wondering – the picture above is just a stock image of a barn. It is rather pretty though! They plan on having shared work spaces in larger buildings, as well as private cabins for people to stay in.

[Thanks KwartsLab!]

Solar Powered Lawn Mower Cuts The Grass So You Don’t Have To

MowerFea2

It takes a lot of power and energy to keep grass levels down to an appropriate level; especially when it’s hot out. If cool glasses of lemonade aren’t around, the task at hand may not be completed any time soon causing the unkempt blades of green (or yellow) vegetation outside to continue their path of growth towards the sun.

Instead of braving the oven-like temperatures which will inevitably drench the person in sweat, this solar powered robot has been created ready to take on the job. With the heart of an Arduino, this device shaves down the grass on a regular basis, rather than only chopping down the material when it gets too long. This helps to save electricity since the mower is only dealing with young and soft plants whose heads are easily lopped off without much effort.

Internally, the robot’s circuitry interfaces with an underground wiring system that defines the cutting zones within the lawn, and proves to be a simple, accurate, and reliable approach to directing the robot where to go. If the device travels under a shaded area, a battery kicks in supplying energy to the engine. When sunlight is available, that same battery accumulates the electricity, storing it for later.

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The BlueOkiris Gameduino Console

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[Dylan] created an easy to make gaming console with an Arduino Uno, a makeshift button, an analog stick, and a TFT LCD touchscreen shield. Plus, he fashioned together a simple button with some duct tape.

So far, he has made 2 games. One is the infamous Pong. The other is a ‘Guess the Number’ type experience. The whole project is run within the code, and does not access the bootloader directly like you would with 2boots or a regular Gameduino adapter.

Build instructions can be found on [Dylan]’s hackaday.io project page (linked above). Essentially, all that is needed is to gather up the supplies, then take the button and analog stick and complete a circuit, fitting the open wires into the slots at digital pin 9. Solder the wires in place and connect ground to ground, 5v to 5v, x to A4, and y to A5. Add the TFT shield, insert a micro SD card, and upload a game.

To see it in action, check out the video after the break:

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Building The NSA’s Tools

Fake ANT Catalog Entry for HackRF

Back in 2013, the NSA ANT Catalog was leaked. This document contained a list of devices that are available to the NSA to carry out surveillance.

[Michael Ossmann] took a look at this, and realized that a lot of their tools were similar to devices the open source hardware community had built. Based on that, he gave a talk on The NSA Playset at Toorcamp 2014. This covered how one might implement these devices using open hardware.

The above image is a parody of an ANT Catalog page, which shows [Michael]’s HackRF, an open source software defined radio. In the talk, [Michael] and [Dean Pierce] go over the ANT Catalog devices one by one, discussing the hardware that would be needed to build your own.

Some of these tools already have open source counterparts. The NIGHTSTAND WiFi exploitation tools is essentially a WiFi Pineapple. SPARROW II is more or less a device running Kismet attached to a drone, which we’ve seen before.

A video of the Toorcamp talk is available on [Michael]’s blog. There will also be a variety of talks on this subject at DEFCON next week, which we’re looking forward to. For further reading, Wikipedia has a great summary of the ANT Catalog.

Arduino SPI Library Gains Transaction Support

Transaction SPI Timing
Transaction SPI Timing

To prevent data corruption when using multiple SPI devices on the same bus, care must be taken to ensure that they are only accessed from within the main loop, or from the interrupt routine, never both. Data corruption can happen when one device is chip selected in the main loop, and then during that transfer an interrupt occurs, chip selecting another device. The original device now gets incorrect data.

For the last several weeks, [Paul] has been working on a new Arduino SPI library, to solve these types of conflicts. In the above scenario, the new library will generate a blocking SPI transaction, thus allowing the first main loop SPI transfer to complete, before attempting the second transfer. This is illustrated in the picture above, the blue trace rising edge is when the interrupt occurred, during the green trace chip select. The best part, it only affects SPI, your other interrupts will still happen on time. No servo jitter!

This is just one of the new library features, check out the link above for the rest. [Paul] sums it up best: “protects your SPI access from other interrupt-based libraries, and guarantees correct setting while you use the SPI bus”.