Accessing Blockchain On ESP8266 Using The NodeMCU Board

May 2, 2018 by 24 Comments

Blockchains claim to be public, distributed, effectively immutable ledgers. Unfortunately, they also tend to get a little bit huge – presently the Bitcoin blockchain is 194GB and Ethereum weighs in at 444GB. That poses quite an inconvenience for me, as I was looking at making some fun ‘Ethereum blockchain aware’ gadgets and that’s several orders of magnitude too much data to deal with on a microcontroller, not to mention the bandwidth cost if using 3G.

Having imagined a thin device that I could integrate into my mobile phone cover (or perhaps… a wallet?) dealing with the whole blockchain was clearly not a possibility. I could use a VPS or router to efficiently download the necessary data and respond to queries, but even that seemed like a lot of overhead, so I investigated available APIs.

As it turns out, several blockchain explorers offer APIs that do what I want. My efforts get an ESP8266 involved with the blockchain began with two of the available APIs: Ethplorer and Etherscan.

Continue reading “Accessing Blockchain On ESP8266 Using The NodeMCU Board” →

Scotty Allen Builds A USB Drive From An IPhone

May 2, 2018 by 13 Comments

What happens when you come across a mysterious, partially populated circuit board in the Huaqiangbei electronics market in Shenzhen? If you’re [Scotty Allen], the only answer is to make your own USB drive from iPhone parts.

[Scotty] made a name for himself through his YouTube channel Strange Parts where he built his own iPhone from scratch, added a headphone jack to an iPhone, and other various exploits involving hot air in Shenzhen. This latest build is no different. It begins with a random PCB [Scotty] found at the electronics market. It has a USB port on one end, it has pads for an iPhone memory chip, and it has an IC that looks like a USB to Flash converter.

The build involved finding a few broken iPhones, desoldering and reballing their Flash chips, and when those didn’t work, finding the correct Flash chips for this tiny little USB adapter board. Here, [Scotty] ran into trouble. The first Flash chip didn’t have the right pins, there was blue smoke, and the toolchain for initializing the USB to Flash IC was a mess.

In the end, [Scotty] managed to create a USB Flash drive after five or six visits to the electronics market, two stencils to reball Flash chips, and finding the OEM software for the USB to Flash chip on this very special PCB. That, itself, required Windows (the horror!), and finding the right version of the software.

Is this technically building a Flash drive purely from disposed iPhone components? We’d quibble. But is it a cool build, regardless? Absolutely. And the real story here is how quickly [Scotty] could iterate on his engineering. When the greatest electronics market is right around the corner, you can do anything with a microscope and a hot air gun.

Tron Inspired LED Desk Lighting

May 2, 2018 by 26 Comments

Reddit user [barbarisch] thought his computer desk was a bit boring, so he came up with a cool project to spice it up: A Tron-inspired computer desk with embedded LED strips!

[Barbarisch] took a basic desk and replaced the tops with ¾” oak plywood. The LED routes were planned out on the computer first and then marked out on the plywood. Using straightedges, [barbarisch] carefully used a router to create the straight grooves and then he created a jig for doing the circles. A bit of trimming and sanding and the three pieces of the desk match up.

After painting the desk, it was time to take a crack at the LEDs. Originally, [barbarisch] thought about 3D printing some diffusers to cover the individual WS2812B lights, but it wasn’t coming out to his liking, so diffusers have been put on the back-burner for now. Holes were drilled in the desk so that connections could be made between the different parts of the grooves and soldering was done between bits of the strips when turning corners. The whole thing’s being controlled by a Raspberry Pi and a Fadecandy USB controller for RGB strips. [Barbarisch] modified a Pi case so that the Fadecandy board would fit as well as printing out a bracket to mount the hardware under the desk.

A fun project to update that boring computer desk and to help you out, the python code which communicates with the Fadecandy server has been put up on GitHub. From the Reddit discussion, it looks like [barbarisch] might have found a solution for diffusing the LEDs! If it’s an LED desk you’re interested in, though, we’ve seen interactive LED tables and Mega LED desks before!

Continue reading “Tron Inspired LED Desk Lighting” →

Hair Today, Gone Tomorrow, Via Electrolysis

May 1, 2018 by 13 Comments

We think of electrolysis as a way to split things like water into oxygen and hydrogen using electricity, but it has a second meaning which is to remove hair using electricity. An electrologist inserts very thin needles into each hair follicle and uses a burst of electricity to permanently remove the hair. [Abbxrdy] didn’t want to buy a cheap unit because they don’t work well and didn’t want to spend on a professional setup, so designing and building ensued.

You’ll have to read through the comments to find some build details and the schematic. The device uses commercial electrolysis needles and a DE-9 connector socket as a holder. The device can supply 6 to 22V at up to 2mA. A timer can restrict the pulse to 5 seconds or less.

Continue reading “Hair Today, Gone Tomorrow, Via Electrolysis” →

Digikey Tips Its Hat To Kicad With Its Own Library

May 1, 2018 by 51 Comments

Digikey might wow us with their expansive stock, but now they’re wowing us with a personal gesture. The US-based electronics vendor is nodding its head in approval to KiCad users with its very own parts library. What’s more, [Chris Gammell] walks us through the main features and thought process behind its inception.

With all the work that’s going into this library, it’s nice to see features showing that Digikey took a thorough look at KiCad and how it fits into the current state of open-source PCBA design. First off, this library follows a slightly different design pattern from most other KiCad libraries in that it’s an atomic parts library. What that means is that every symbol is linked to a specific manufacturer part number and, hence, gets linked to a specific footprint. While this style mirrors EagleCad’s; KiCad libraries usually separate symbols from footprints so that symbols can be reused and parts can be more easily swapped in BOMs. There’s no “best” practice here, so the folks at Digikey thought they’d expose the second option.

Next off, the library is already almost 1000 parts strong and set to grow. These aren’t just the complete line of Yageo’s resistor inventory though. They actually started cultivating their library from the parts in Seeed Studio’s open parts library. These are components that hobbyists might actually use since some assembly services have a workflow that moves faster with designs that use these parts. Lastly, since all parts have specific vendor part numbers, BOM upload to an online cart is more convenient, making it slightly easier for Digikey to cha-ching us for parts.

Yes, naysayers might still cry “profit” or “capitalism” at the root of this new library, but from the effort that’s gone into this project, it’s a warm gesture from Digikey that hits plenty of positive personal notes for hobbyists. Finally, we can still benefit from plenty of the work that’s gone into this project — even if we don’t use it as intended. The permissive license lets us snag the symbols and reuse them however we like. (In fact, for the sharp-eyed legal specialists, they actually explicitly nullified the clause stating that derivative projects need not be licensed with a creative-commons license.)

With maturing community support from big vendors like Digikey, we’re even hungrier to get our hands on KiCad V.

Continue reading “Digikey Tips Its Hat To Kicad With Its Own Library” →

A Telepresence System That’s Starting To Feel Like A Holodeck

May 1, 2018 by 30 Comments

[Dr. Roel Vertegaal] has led a team of collaborators from [Queen’s University] to build TeleHuman 2 — a telepresence setup that aims to project your actual-size likeness in 3D.

Developed primarily for business videoconferencing, the setup requires a bit of space on both ends of the call. A ring of stereoscopic z-cameras capture the subject from all angles which the corresponding projector on the other end displays. Those projectors are arranged in similar halo above a human-sized, retro-reflective cylindrical screen which can be walked around — viewing the image from any angle without a VR headset or glasses — in real-time!

Continue reading “A Telepresence System That’s Starting To Feel Like A Holodeck” →

See-Through Rotary Engine Reveals Wankel Magic

May 1, 2018 by 25 Comments

The Wankel rotary engine is known for its troubled life in the mainstream automotive industry, its high power-to-weight ratio, and the intoxicating buzz it makes at full tilt. Popular with die-hard enthusiasts and punishing to casual owners, it stands as perhaps the most popular alternative internal combustion design to see the light of day. There are myriad diagrams out there to explain its operation, but what if you could see inside?

The video comes courtesy of [Warped Perception], and features a small Wankel rotary engine intended for model aircraft. The engine’s end plate is removed and replaced with a transparent plate, making the combustion process visible. Add in a high-speed camera, and you’ve got a recipe for a great technical video.

It starts with a basic explanation of how the Wankel rotary power cycle operates, before cutting to the glorious slow-motion shots of the engine in operation. It also highlights several techniques useful for producing this type of video, such as painting surrounding components black to make it easier to image the parts of interest. The visuals are amazing and very clearly show the  manner in which the intake, compression, power and exhaust strokes function in the engine.

Continue reading “See-Through Rotary Engine Reveals Wankel Magic” →