Drawbot software aims to do it better than the rest


There are plenty of drawbot projects out there, many of which come with their own special software in tow. While some of these packages are easier to use than others, [Dan Royer] is pretty sure he can do it better.

Looking for a fun and engaging way to teach STEM subjects in schools across the country, [Dan] developed a relatively simple drawbot which can be constructed by a wide range of age groups. While he is trying to get schools to purchase his robot kits, we’re guessing that our readers would be more inclined to build their own.

So what does [Dan] have to offer that might interest you? Well, he says he has developed some drawbot software that’s pretty darn easy to use. Rather than multiple applications generating machine-specific code, his software will transform your picture into a line drawing in one easy step. The app uses a traveling-salesman algorithm to generate drawings with nary a crossed line in sight before outputting the resultant machine instructions in easy-to-use GCode.

We don’t have a drawbot of our own handy to test his software out, so if you do happen to give it a shot, let us know how it worked for you in the comments.

Building an artificial moon for Burning Man


If you were lucky enough to score passes to this year’s Burning Man, be sure to keep a look out for [Laurence Symonds] and crew, who are putting together an ambitious fixture for the event. In reality, we’re guessing you won’t have to look far to find their giant moon replica floating overhead – in fact it will probably be pretty hard to miss.

They are calling the sculpture “Lune and Tide”, which of an 8 meter wide internally lit moon which hovers over a spinning platform that’s just as big across. The inflatable sphere is made up of giant ripstop nylon panels which are home to 36,000-odd sewn-in LEDs. The LEDs illuminate the sphere to reflect the natural color of the moon, though with a simple command, [Laurence] and Co. can alter the lighting to their heart’s content.

If Hack a Day’s [Jesse Congdon] makes his way out to the festival again this year, we’ll be sure he gets some footage of Lune and Tide in action. For now, you’ll have to satisfy your curiosity by checking out the project’s build log.

Gaining low-level SPI access on the Raspberry Pi

Raspberry Pi - rpi

We’ve seen a ton of projects that interface hardware with the Raspberry Pi. But they usually depend on bit-banging. That means they toggle the pins in software to match a specific protocol. The thing is that the beefy Broadcom SoC that anchors the board has a lot of built-in peripherals that are just waiting to be used instead of bit banging. In this case, it’s the hardware SPI peripheral which can be accessed via the bcm2835 library for RPi.

One of the things that would have really complicated this process is the pin mapping between the Broadcom chip and the RPi GPIO header. Since not all pins are broken out, it was either luck or good design forethought that made all of the SPI0 pins from the chip available on the RPi breakout header. The library page (linked above) explains this well. But if you’re looking for more of a working example check out [EngineerByNight's] project with adds an accelerometer using hardware SPI.

Girl decides to restore a car in time for her 16th birthday

When, born hacker, [Kathryn] was 12, she approached her parents with an interesting proposition; she wanted to restore a Pontiac Fiero before her 16th birthday. So, using her babysitting money, parental guidance, and an enviable attitude, she has set out to do just that. The build log linked above is  incomplete as she has not yet reached 16, but is a very good read. Lots of build logs gloss over some of the more basic steps because they’ve done this a time or two. It’s fun to learn along with [Kathryn] as she and her dad work all the way from upholstery and painting to grinding and welding wheel wells.  It seems this project has acquired quite a fan base over the past few months, us included, and even a 3M sponsorship. We look forward to seeing what [Kathryn] does next. It looks like some engine work, along with a lot more welding.

Didn’t [Jeri Ellsworth] have a history of building cars too?

A much larger rainbow board of many ping pongs

[George] started with an 8×8 grid, but just couldn’t help himself from upscaling to this 32×16 pixel ping pong ball display. That’s right, It’s a 512 pixel array of fully addressable RGB LEDs diffused with one ping pong ball each.

We featured the predecessor to this project back in January. That one was an 8×8 display using a Rainbowduino as the controller. [George] took what he learned from that build and expanded upon it. The larger display is modular. Each module starts as an 8×8 grid which connects back to the Arduino using a breakout shield with some Ethernet jacks used as quick connects. The LEDs are driven by 595 shift registers, with transistors which protect the logic chips from the currents being switched.

He had a lot of help soldering all the connections for the display and ended up bringing it to show off at the Manchester mini maker faire. See it in action in the video after the break.

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Force carbonating root beer with dry ice

[Paul] is sick and tired of his homemade root beer being flat. He analyzed the problem with his carbonation techniques and ended up with a method of force carbonating beverages using dry ice.

He starts of by discussing the various methods that are used to carbonate beverages. There’s the old yeast and sugar trick that takes place inside of a sealed bottle. But this takes time, and if you don’t calculate the mixture correctly you could have over or under carbonated bottles (or exploding bottles in the case of glass beer bottling). [Paul] himself has tried the dry ice in a cooler full of root beer method. The problem is that the cooler isn’t pressurized so the carbonation level is very low. You need to have cold temperatures, high pressure, and the presence of carbon dioxide all at the same time in order to achieve high levels of carbonation.

His solution is to use a 60 PSI safety valve. He drilled a hole in a plastic bottle cap to receive the valve. He then drops a few chunks of dry ice in and seals it up. The valve will automatically release the gas as the pressure builds past the 60 PSI mark. What he ends up with is a highly carbonated beverage in a matter of minutes.

If you don’t mind spending some cash you can use an adjustable pressure regulator. This way you can carbonate just about anything.

[Thanks Steven]

Make a cardboard bookshelf in less than a day

Lucas came up with a real winner when upcycling cardboard to use as a bookshelf. It’s visually pleasing, can be built basically for the cost of glue and a mounting brackets, and you don’t have to feel bad if you decide to get rid of it later on.

What he saved in raw material cost he spent in labor. There are 23 different layers of cardboard that went into the project, not including the spacer squares between each piece. The vast majority of the time spent in the clip after the break shows a fast-time video of him cutting out the layers. It apparently took about eight hours of cutting, and we’d image he’s got a claw of a hand after all of that work.

This is hanging from a single L bracket positioned in the square opening with two nails to keep it level. We’d suggest including a better mounting technique in your design. If you have some ideas about this please let us know in the comments.

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