The Wheatstone bridge is a way of measuring resistance with great accuracy and despite having been invented over 150 years ago, it still finds plenty of use today. Even searching for it on Hackaday brings up its use in a number of hacks. It’s a fundamental experimental device, and you should know about it.
Is it possible to recycle failed 3D prints? As it turns out, it is — as long as your definition of “recycle” is somewhat flexible. After all, the world only needs so many coasters.
To be fair, [Devin]’s experiment is more about the upcycling side of the recycling equation, but it was certainly worth undertaking. 3D printing has hardly been reduced to practice, and anyone who spends any time printing knows that it’s easy to mess up. [Devin]’s process starts when the colorful contents of a bin full of failed prints are crushed with a hammer. Spread out onto a properly prepared (and never to be used again for cookies) baking sheet and cooked in the oven at low heat, the plastic chunks slowly melt into a thin, even sheet.
[Devin]’s goal was to cast them into a usable object, so he tried to make a bowl. He tried reheating discs of the material using an inverted metal bowl as a form but he found that the plastic didn’t soften evenly, resulting in Dali-esque bowls with thin spots and holes. He then flipped the bowl and tried to let the material sag into the form; that worked a little better but it still wasn’t the win he was looking for.
In the end, all [Devin] really ended up with is some objets d’art and a couple of leaky bowls. What else could he have done with the plastic? Would he have been better off vacuum forming the bowls or perhaps even pressure forming them? Or does the upcycling make no sense when you can theoretically make your own filament? Let us know in the comments how you would improve this process.
Continue reading “Fail Of The Week: Upcycling Failed 3D Prints”
NASA has a bunch of its 3D models up on GitHub, and if you didn’t know about it before, you do now. It’s a ridiculously large download, at over one and a half jiggabytes, but it’s full of textures and high-resolution models of spacecraft, landing sites, and other random NASA ephemera.
[Netzener] received a Radio Shack P-Box one tube receiver as a gift. However, at the time, his construction skills were not up to the task and he never completed the project. Years later, he did complete a version of it with a few modern parts substitutions. The radio worked, but he was disappointed in its performance. Turns out, the original Radio Shack kit didn’t work so well, either. So [Netzener] did a redesign using some some old books from the 1920’s. The resulting radio — using parts you can easily buy today — works much better than the original design.
The most expensive part of the build was a 22.5 V battery, which cost about $25. However, you can get away with using three 9 V batteries in series if you want to save some money. The battery provides the plate voltage for the 1T4 vacuum tube. A more conventional AA battery drives the tube’s filament. The original Radio Shack design relied on a variable inductor for tuning. These are difficult to find now, so [Netzener] uses a more conventional adjustable coil and a common tuning capacitor.
As an extra touch, [Netzener] painted the perf board to look as much like the original Radio Shack kit as possible. You can see from the pictures, it came out looking very good. If this isn’t challenging enough for you, maybe you want to roll your own tube. Or maybe you should just settle for the socket.
Lots of useful things come in boxes. Shoes, soldering irons and… prime numbers? This simple project from [WhiskyTangoHotel] puts a list of prime numbers in a handy box. Press a button, get a prime.
Sure, it isn’t brain surgery: all that it is happening is that a Raspberry Pi is reading a number from a text file, then showing it on an LCD screen. But it’s well-documented project that shows how to tie together a number of things on the Pi, like writing to an I2C display and using a button to trigger a clean shutdown.
It might be a good starting project for the younger hacker or if you have a Pi pining for something to do. If you’re looking for more easy Raspberry Pi projects, check out our Enlightened Pi Contest.
It’s got a little “Saturday Night Fever” vibe to it, but this pressure-sensitive LED floor was made for gaming, not for dancing.
Either way, [creed_bratton_]’s build looks pretty good. The floor is a 5×6 grid of thick HDPE cutting boards raised up on a 2×4 lumber frame. Each cell has a Neopixel ring and a single force-sensitive resistor to detect pressure on the pad. Two 16-channel multiplexers were needed to consolidate the inputs for the Arduino that’s running the show, and a whole bunch of wall warts power everything. The video below shows a little of the build and a look under the tiles. It’s not clear exactly what game this floor is for, but you can easily imagine a maze or some other puzzle that needs to be solved with footsteps.
Light-up floors are nothing new here, what with this swimming pool dance floor. But this interactive dance floor comes close to the gaming aspect of [creed_bratton_]’s build.
Continue reading “Neopixels Light The Way In Pressure-Sensitive Floor”
A few years ago, someone figured out small, cheap ARM Linux boards are really, really useful, extremely popular, sell very well, blink LEDs, and are able to open the doors of engineering and computer science to everyone. There is one giant manufacturer of these cheap ARM Linux boards whose mere mention guarantees us a few thousand extra clicks on this article. There are other manufacturers of these boards, though, and there is no benevolent monopoly; the smaller manufacturers of these boards should bring new features and better specs to the ARM Linux board ecosystem. A drop of water in a tide that lifts all boats. Something like that.
This week, Orange Pi, not the largest manufacturer of these small ARM Linux boards, has released two new boards. The Orange Pi Zero is an inexpensive, quad-core ARM Cortex A7 Linux board with 256 MB or 512 MB of RAM. The Orange Pi PC 2 is the slightly pricier quad-core ARM Cortex-A53 board with 1 GB of RAM and a layout that can only be described as cattywampus. We all know where the inspiration for these boards came from. The price for these boards, less shipping, is $6.99 USD and $19.98 USD, respectively.
The Orange Pi Zero uses the Allwinner H2 SoC, and courageously does not use the standard 40-pin header of another very popular line of single board computers, although the 26-pin bank of pins is compatible with the first version of the board you’re thinking about. Also on board the Orange Pi Zero is WiFi provided by an XR819 chipset, Ethernet, a Mali400MP2 GPU, USB 2.0, a microSD card slot, and a pin header for headphones, mic, TV out, and two more USB ports.
The significantly more powerful Orange Pi PC 2 sports a quad-core ARM Cortex-A53 SoC coupled to 1 GB of RAM. USB OTG, a trio of USB 2.0 ports, Ethernet, camera interface, and HDMI round out the rest of the board.
Both of Orange Pi’s recent offerings are Allwinner boards. This family of SoCs have famously terrible support in Linux, and the last Allwinner Cortex-A53, that we couldn’t really review, was terrible. Although the Orange Pi Zero and Orange Pi PC 2 are new boards and surely software is still being written, history indicates the patches written for this SoC will not be sent upstream, and these boards will be frozen in time.
If you’re looking for a cheap Linux board with a WiFi chipset that might work, The Orange Pi Zero is very interesting. The Orange Pi PC 2 does have slightly impressive specs for the price. When you buy a single board, though, you’re buying into a community dedicated to improving Linux support on the board. From what I’ve seen, that support probably won’t be coming but I will be happy to be proven wrong.
