How To Bend PVC The Nice Way

October 27, 2017 by 32 Comments

PVC pipe is a valuable material to the backyard hacker. It’s cheap, readily available, and comes in a range of different sizes. However, what do you do if you need to bend it? The typical approach would be to grab a heat gun or blowtorch, warm it up, and go from there. These methods can get messy however, with kinks and melted surfaces spoiling the final result. Now [Linn] has released a video with a method that delivers impressively neat results.

A bending jig can help create repeatable results.

The method is simple, using that classic hacker staple — duct tape. The end of the pipe is taped off, and the pipe filled with sand. With the correct amount measured out, the sand is heated on a cooktop, then poured back into the pipe. After giving the heat some time to soften the plastic, the pipe can then be manipulated into the desired shape.

[Linn] does a great job of explaining the process in a clear and concise manner, and shares tips on how to use a bending jig to guide the final shape. Results are best with smaller pipes that are easier to heat through, but larger sections can be manipulated with patience.

We can’t wait to see what [Linn] builds with this new technique. The possibilities could be further expanded by combining with these PVC fittings designed just for building stuff.

[Thanks to George for the tip!]

Skynet Will Have Bobcats

October 26, 2017 by 40 Comments

There are so many autonomous devices nowadays that can run Skynet Inside(TM) that it’s hard to keep track. But one was still missing: the versatile Bobcat. When we say “Bobcat”, we mean track loader — it’s just one of those things that the name and the brand stoke together so strongly that it’s hard to actually recall the technical name. A company by the name of Built Robotics is betting on autonomous track loaders as being a big part of the future of construction.

The tractor can navigate, excavate, and carry a 1,000 pound load with 1 cm precision using its LIDAR, specially designed to work with high-vibration, high-impact environment of construction excavation. Additionally, the lasers also allow the robot to measure the amount of material it has scooped up. But the precision does not come from the LIDAR alone. To position the robot, Built Robotics uses augmented GPS, which combines an on-site base station and GPS satellites to produce accurate location data.

It is supposed to be completely autonomous: given a location and holes to dig, it can plan and execute the work. It resembles a self-driving car, but the challenges are actually quite different. Cars are mean to drive around and reach a destination without touching anything. Like the CEO of Built Robotics says:

“If a car is changing the environment around it, then something’s gone really wrong.”

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Hollow State Memory

October 26, 2017 by 12 Comments

A lot of people like tubes either for their audio sound or their collectible value. [Uniservo] likes oddball tubes. His recent video (see below) shows a radechon — a computer memory tube. These were apparently widely used in RADAR sets until recently and has some similarity to a Williams tube.

The tube is essentially a CRT that illuminates a sheet of mica or another dielectric instead of a phosphor screen. The dielectric has a fine mesh grid in contact with it. By depositing charge on the mica, the tube can store an analog value. In theory, the tube could store about 16 kbits of information, but in practice, the resolution was less.

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Thermite Creates A Sword

October 26, 2017 by 26 Comments

Thermite can cut cars in half but [TheBackyardScientist] relies on its ability to create rather than destroy. In fact, thermite was the key component when he casts a solid metal sword. The casting doesn’t require a furnace since the heat is produced by the thermite itself.

In case it wasn’t abundantly clear: this procedure is not without risk.

[TheBackyardScientist] compares two types of iron oxide, red and black, then judges their usability based on the post-ignition mass. His goal is to get the most metal from a single reaction. He also adds some stainless steel beads to improve the quality of the casting and to utilize some of the excess heat.

With encouragement from his neighbors and a couple of trials with fire bricks, buckets, and sand, [TheBackyardScientist] is successful. The resulting sword is treated, given a handle, sharpened, then scientifically tested with a variety of things found in a regular kitchen.

If you look in the background of [TheBackyardScientist]’s workshop, you may notice his molten PEWter gun. This steel sword is an upgrade from his recycled pewter sword a few years ago.

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Reconstructing A Blurry QR Code

October 26, 2017 by 4 Comments

QR Codes are a two-dimensional type of matrix barcode that are used for a variety of uses. They’re one way of turning a long piece of string data into an easily machine-readable format. For this reason, they can be used to store private keys for encryption and crypto-currency purposes. [Roger Ver] attempted to use a QR code containing a private key to give away some cryptocurrency on TV, but the code was blurred out by the broadcaster. Not ones to give up easily, [Michael] and [Clément] decided to see if they could reconstruct it anyway. 

The work begins, as so many cryptographic exploits do, with the collection of as much of the plaintext key as possible. By stepping through the footage frame by frame, small pieces of the unobscured QR code were found, as well as some of the private key itself. By combining this with enhanced images of the blurred code, the team were able to put together less than one third of the QR code. The team had other tricks up their sleeve though – they knew the QR contained a private key of a particular format, and were able to figure out the QR code was 41×41 pixels.

By using this data along with a careful study of the QR code format, the team were able to put together some code in Python to brute force the key. After 838849 trials, the key was found, and the team were able to claim the prize. It’s a great example of cryptographic analysis – and so is this story on hacking your own password.

[Thanks to Esko for the tip!]

Hackaday Prize Entry: The Minimalist Z80 Computer

October 26, 2017 by 22 Comments

The best projects always seem to come from eBay. A few weeks ago, we found a few tiles meant for gigantic LED panel installations, and fifty bucks got you ten tiles. That eBay auction is now sold out. A while ago, [Just4Fun] realized he could build a Z80 microcomputer with $4 worth of parts from everyone’s favorite online auction house. The result is a $4 Z80 home computer, and a great Hackaday Prize entry to boot.

So, what do he need to build a retrocomputer loaded up with Forth, CP/M, and Basic? A CPU is a necessity, and [Just4Fun] found a Z80 (technically a Z84C00) for just a bit more than a dollar. A computer will need some RAM too, and a 128 kiB parallel SRAM was just the ticket for another dollar.

Here’s where things get a bit more interesting. Where the retrocomputers of yore were loaded up with glue logic, PLAs, or other weird chips, modern technology has come a long way. Instead of a massive amount of glue, [Just4Fun] is using an ATmega32A for all the I/O, address decoding, and a serial terminal.

The ATmega thrown into this cornucopia of vintage chips is itself more than a decade old, but it does have 40 pins and 32 kiB of Flash. That’s enough to ‘virtualize’ all the peripherals you’d need on a Z80 bus and provide the clock signal for the rest of the computer.

This home computer was originally designed and laid out on a solderless breadboard, but [WestfW] managed to stuff this all onto a small PCB. That’s a cheap computer that gets you all the retrocomputing goodies, and it’s something that’s just random enough to be a perfect entry for the Anything Goes portion of the Hackaday Prize.

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The Most Useless Tools You Can’t Seem To Part With

October 26, 2017 by 180 Comments

I’m a tool person. No matter how hard I try, I eventually end up with a bunch of tools that I just can’t bear to banish from my workshop. Why? I’m gonna keep it 100%: it’s the same emotion behind hoarding — fearing that you might need a thing later and not be able to have it.

The stuff costs money, and if you have to script to buy a bunch of tools pertaining to Project X, you expect to still have and probably need those very same tools — even if they have to sit in a box on my shelf for 20 years, taunting me every time I have to move it to one side.  “Heat-bending element” the box’s label describes at tool I haven’t used in at least 5 years. I have a bunch of these white elephants. I’ll probably need to heat-bend acrylic real soon… yeah.

I’ve found that pretty much everyone in our crowd can relate. You buy a special tool for one project and it was expensive and tremendously helpful, and since then it’s been sitting around uselessly. You certainly couldn’t part with it, what if you needed it again? So you store it in your house for 20 years, occasionally coming across it when looking for something else, but it never actually gets used.

Join me now in a walk down our memory lane of useless tools.

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