Friday Hack Chat: JavaScript On Microcontrollers

August 23, 2017 by Brian Benchoff 15 Comments

Microcontrollers today are much more powerful and much more capable than the 8051s from back in the day. Now, they have awesome peripherals and USB device interfaces. It’s about time a slightly more modern language was used to program these little chips.

During this Friday’s Hack Chat, we’re going to be talking about JavaScript on microcontrollers. [Gordon Williams] will be joining us to talk about Espruino. This is a tiny JavaScript interpreter that runs on the little embedded chips, has a debug interface, and allows you to program your board on any platform without any external programming hardware.

[Gordon] is the key developer of Espruino, and so far he’s launched a full-sized Espruino, and a pico Espruino on Kickstarter, both with amazing success. The software stack has been extremely popular as well — it’s been ported to the ESP8266 and dozens of other microcontrollers that will soon be in the Internet of Things.

During the Hack Chat, we’ll be discussing interpreted languages on microcontrollers, interpreter design and optimization, with a special emphasis on creating devices with Espruino and putting Espruino boards on the Internet with WiFi, Bluetooth, and other crazy radios. As always, we have a spreadsheet open to everyone if you’d like to ask a question.

Here’s How To Take Part:

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. Hack Chats are mostly, usually, and this week noon, Pacific time on Friday. Here’s a time and date converter!

Log into Hackaday.io, visit that page, and look for the ‘Join this Project’ Button. Once you’re part of the project, the button will change to ‘Team Messaging’, which takes you directly to the Hack Chat.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Wood Finish From Old Records

August 23, 2017 by Adam Fabio 36 Comments

Next time you’re working on a project that needs a durable wood finish, don’t grab the polyurethane. Follow [Victor Ola’s] advice and raid your grandparent’s record cabinet for some old 78 records. Modern records are made from vinyl. The stiff, brittle old 78’s from the 1960’s and earlier were made from shellac. Shellac is a natural material secreted by the female lac bug. It can be thought of as a natural form of plastic and was used as such for years until man-made plastics became commodity items.

Older 78 RPM phonograph albums are usually made entirely from shellac. [Victor] started by taking a few old cracked records and pulverizing them with a hammer. The shellac crumbs were then poured into a mason jar along with some isopropyl alcohol. The alcohol dissolves the shellac, creating a thick goo. More alcohol will thin the slurry down to a paintable consistency. The mixture is then ready to be painted on any wood surface. Wiping off the excess will reveal the wood grain.

Shellac is normally amber in color. Records are black because carbon is added to the mix. This makes the shellac stain dark and makes it a flat finish. While it would be fine to leave it this way, [Victor] added a coat of lacquer over his shellac stain to achieve a glossy finish on his upcycled gramophone.

If you’re getting into woodworking, don’t worry – anyone can do it. Just make sure you have sharp tools.

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The Last Interesting Chrysler Had A Gas Turbine Engine

August 23, 2017 by Bryan Cockfield 137 Comments

The piston engine has been the king of the transportation industry for well over a century now. It has been manufactured so much that it has become a sort of general-purpose machine that can be used to do quite a bit more than merely move people and cargo from one point to another. Running generators, hydraulic systems, pumps, and heavy machinery are but a few examples of that.

Scale production of this technology also had the effect of driving prices for these engines down, and now virtually everyone in the developed world has cheap and easy access to them. In the transportation world, at least, it looks like its reign might finally be coming to a slow, drawn-out conclusion as electric cars capture more and more market share.

Electric motors aren’t the first technology to try to topple the piston engine from its apex position on top of our modern transportation industry, though. In the 1960s another technology, the gas turbine engine, tried to replace it — and failed.

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Make Your Own Compound Bow From PVC Pipe

August 23, 2017 by Jack Laidlaw 25 Comments

Have you ever wanted to make your own compound bow for fun or even fishing? [New creative DIY] shows us how in their YouTube video. Compound bows are very powerful in comparison to their longbow grandparents, relying on the lever principle or pulleys. meaning less power exertion for the same output.

Compound bows can be really sophisticated in design using pulleys and some exotic materials, but you can make your own with a few nuts and bolts, PVC pipe, string and a tyre inner tube. The PVC pipe can be melted into shape using a heat source such as a portable stove or even a blow torch, and once you have shaped your bow you will want to put a small piece of pipe at both ends with a nut and bolt. Then you can use rubber to give the flexibility your bow needs to shoot arrows, using the tyre inner tube cut to the right size. A piece of string for the ends of your arrows to rest on is then all you need, attach this to either end of your pipe and you should have a DIY PVC compound bow ready for shooting arrows. Alternatively you could always make a recurve bow out of skis.

–Update [Leithoa] in the comments has pointed out this is neither a bow nor a compound and that they are often confused. This is actually a slingshot, of sorts.–
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From Foot Pump Cylinders To Pneumatic Robot Fighting Arm

August 23, 2017 by Steven Dufresne 12 Comments

[James Bruton] is well known for making robots using electric motors but he’s decided to try his hand at using pneumatics in order to make a fighting robot. The pneumatic cylinders will be used to give it two powerful punching arms. In true [James Bruton] fashion, he’s started with some experiments first, using the pneumatic cylinders from foot pumps. The cylinders he’s tried so far are taken out of single cylinder foot pumps from Halfords Essentials, costing only £6.29, around $8.11 US. That’s far cheaper than a commercial pneumatic cylinder, and perfectly adequate for this first step.

He did have to hack the cylinder a little though, besides removing it from its mounting and moving it to a DIY frame. Normally when you step down on a foot pump’s lever, you compress the cylinder, forcing air out the hose and into whatever you’re inflating. But he wanted to push air in the other direction, into the hose and into the cylinder. That would make the cylinder expand and thereby extend a robot fighting arm. And preferably that would be done rapidly and forcefully. However, a check valve at the hose outlet prevented air from entering the cylinder from the hose. So he removed the check valve. Now all he needed was a way to forcefully, and rapidly, push air into the hose.

For that he bought a solenoid activated valve on eBay, and a compressor with a 24 liter reservoir and a decent air flow rate of 180 liters per minute. The compressor added £110 ($142) to the cost of his project but that was still cheaper than the batteries he normally buys for his electric motor robots.

After working his usual CAD and 3D printing magic, he came up with an arm for the cylinder and a body that could fit two more valve activated cylinders to act as a working shoulder. A little more 3D printing and electronics, and he had 3 switches, one for each valve and cylinder. He then had the very successful results his experiment. You can see the entire R&D process in the video below, along with demonstrations of the resulting punching robot arm. We think it’s fairly intimidating for a first step.

Continue reading “From Foot Pump Cylinders To Pneumatic Robot Fighting Arm” →

Sniff Your Local LoRa Packets

August 22, 2017 by Jenny List 15 Comments

As the LoRa low-bandwidth networking technology in license-free spectrum has gained traction on the wave of IoT frenzy, LoRa networks have started to appear in all sorts of unexpected places. Sometimes they are open networks such as The Things Network, other times they are commercially available networks, and then, of course, there are entirely private LoRa installations.

If you are interested in using LoRa on a particular site, it’s an interesting exercise to find out what LoRa traffic already exists, and to that end [Joe Broxson] has put together a useful little device. Hardware wise it’s an Adafruit Cortex M0 Feather with onboard LoRa module, paired with a TFT FeatherWing for display, and software wise it scans a set of available frequencies and posts any packets it finds to the scrolling display. It also has the neat feature of logging packets in detail to an SD card for later analysis. The whole is enclosed in a 3D printed case from an Adafruit design and makes for a very attractive self-contained unit.

We’ve featured quite a few LoRa projects here, including this one with a Raspberry Pi Compute module in a remote display. Of more relevance in a LoRa testing sense though is this look at LoRa range testing.

Yes, Of Course Someone Shot The Eclipse On A Game Boy Camera

August 22, 2017 by Mike Szczys 24 Comments

This one shouldn’t surprise us, but there is something particularly enjoyable about seeing the total eclipse of the Sun through a Game Boy camera.

The Game Boy got its camera accessory back in 1998 when CCD-based cameras with poor resolution were just becoming widely available to the public. This camera can capture 128×112 pixel images in the four value grey scale for which the handheld is so loved.

Having taken part in eclipse mania ourselves we can tell you that unless you did some serious research and prep for photographing the thing, this makes as much sense as pulling out your smartphone did. We posit that it certainly produced a more pleasing result.

[jhx] says this is more a weird halo effect of the shot than it is a quality image of totality. At this resolution, the moon-covered Sun should be very few pixels in size, right? But fidelity is for photographers, this is for hackers. Getting the digital image off of the Game Boy camera involved using an Interact Mega Memory cartridge on a Game Boy Pocket to transfer it over, then using a USB 64M cartridge to copy from the Mega Memory and ultimately to a computer.

Glamour shots ain’t easy, yo. But it is possible to read images directly off the Game Boy camera thanks to some reverse engineering work.

[via Kotaku]