api

79 Articles

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.

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Bargain Bin Barcode Scanner Keeps Track Of Shopping Needs

April 23, 2018 by 18 Comments

For most people, a Post-It note or dry-erase board suffices to ensure that household consumables are replenished when they’re used up. But hackers aren’t like most people, so this surplus barcode scanner turned kitchen inventory manager comes as little surprise. After all, if something is worth doing, it’s worth overdoing.

[Brian Carrigan]’s project began with a chance discovery of an old barcode scanner in his local scrap store. Questions as to why we can never find bargains like a $500 scanner for six bucks aside, [Brian] took the scanner home for a bit of reverse engineering. He knew it used RS-232 but it had been unceremoniously ripped from its connectors, so identifying pins took some detective work. With power and data worked out and the scanner talking to a Raspberry Pi, [Brian] set about integrating it into Wunderlist,  a cloud-based list management app. Now when someone eats the last Twinkie, a quick scan of the package looks up the product name via an API call to the UPC database and posts it to Wunderlist. And we’ll bet the red laser beams bouncing around the kitchen make a great nightlight too.

With smartphone barcode reading apps, this might seem a bit like overkill, but we like it just the same. And if barcodes leave you baffled, check out our introduction to these studies in black and white that adorn just about everything.

GuerillaClock Could Save This City Thousands

April 22, 2018 by 32 Comments

They say necessity is the mother of invention. But if the thing you need has already been invented but is extremely expensive, another mother of invention might be budget overruns. That was the case when [klinstifen]’s local government decided to put in countdown clocks at bus stops, at a whopping $25,000 per clock. Thinking that was a little extreme, he decided to build his own with a much smaller price tag.

The project uses a Raspberry Pi Zero W as its core, and a 16×32 RGB LED matrix for a display. Some of the work is done already, since the bus system has an API that is readily available for use. The Pi receives the information about bus schedules through this API and, based on its location, is able to determine the next bus arrival time and display it on the LED matrix. With the custom 3D printed enclosure and all of the other material, the cost of each clock is only $100, more than two orders of magnitude less expensive.

Hopefully the local government takes a hint from [klinstifen] and decides to use a more sane solution. In the meantime, you might be able to build your own mass transit clock that you can use inside your own house, rather than at the train station, if you’re someone who has a hard time getting to the bus stop on time.

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Internet Of Things Opens Possibilities

December 3, 2017 by 7 Comments

While a lot of hardware gets put on the “Internet of Things” with only marginal or questionable benefits (or with hilariously poor security), every now and then a project makes use of this new platform in a way that illustrates the strengths of IoT. [ThingEngineer] turned to this platform as a cost-effective solution for an automatic gate, since new keyfobs were too expensive and a keypad was not an option.

Using an Electric IMP, [ThingEngineer] began by installing his IoT patch into the LiftMaster gate control box. This particular gate has easily accessible points that the controller can access to determine the gate’s status, so from there, an API was written to do the heavy lifting. A web server was deployed as well, so anyone with access can use a smartphone or other device to open the gate.

For anyone else looking to deploy a similar IoT solution, [ThingEngineer] has put all of the project code, schematics, and a thorough write-up about the project on his GitHub page. There are many useful ways to get on board the Internet of Things, though; so many that it’s been possible to win a substantial prize for using it in a creative way.

Listen To The Netherworld With Artificial Intelligence

October 24, 2017 by 19 Comments

It’s that time of year again, and with Halloween arguably being the hacker’s perfect holiday, we’re starting to see a tick up in projects with a spooky theme. Most seem to do with making some otherwise tame Halloween decorations scarily awesome, but this is different — using artificial intelligence to search for ghosts.

It seems like [Matt Reed]’s “DeepWhisper” project is meant to be taken as light-hearted fun for the spooky season, but there may be a touch of seriousness to his efforts to listen in on ghostly conversations. The principle behind this is electronic voice phenomena (EVP), whereby the metabolically and/or dimensionally challenged are purported to influence electronic systems, resulting in heavily processed audio clips that seem to have a whispered endearment from the departed or a threat from a malevolent spirit. DeepWhisper takes this a step further by using a Raspberry Pi to feed audio into the Google Cloud Speech API for analysis. If anything is whispered in one of the 110 or so languages Google knows, it’ll get displayed on a screen. [Matt] plans to set DeepWhisper up in the aptly-named Butchertown section of Nashville and live-stream the results next week.

It’ll be interesting to see what Google’s neural network makes out of the random noise it will probably only ever hear. And [Matt] is planning on releasing his code for all to see, so there may be some valuable cloud techniques to learn from DeepWhisper. But in the unlikely event that he does discover ghosts, it’s nice to know you can have the tools and the talent to bust ’em.

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Blinking LEDs On The Internet Of Printers

August 25, 2017 by 7 Comments

When you ask for recommendations on which 3D printer to buy, damn the cost, the Ultimaker is consistently at the top of the list. There’s a reason for the popularity of this printer — it’s easy to use, extremely high quality, and has an entire freakin’ Linux system running somewhere under the hood. That last bit is opening up a few doors to some interesting hacks, like using a 3D printer as an RGB LED.

The Doodle3D team has been playing around with the Ultimaker API to see if they can make their software work with the Ultimaker printer. The Ultimaker has RGB LEDs, so obviously the simplest proof of concept in futzing around with an API is to blink a few LEDs. The actual code was written in HTML, JavaScript, and Node in just two hours. The author admits it’s ugly, but it works. Can’t go wrong with that.

While this is just a simple test of the Ultimaker API, it’s surprisingly high up on the Google results when you search, ‘Ultimaker API’. That’s a shame, because there’s a lot of power under the hood of this printer. If you have some sort of mod you’d like to throw into the ring, here’s the Hackaday Tip Line.

You can check out the demo video of this hack below.

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Drone Takes Off With A Flick Of The Wrist

June 18, 2017 by 8 Comments

One of the companion technologies in the developing field of augmented reality is gesture tracking. It’s one thing to put someone in a virtual or augmented world, but without a natural way to interact inside of it the user experience is likely to be limited. Of course, gestures can be used to control things in the real world as well, and to that end [Sarah]’s latest project uses this interesting human interface device to control a drone.

The project uses a Leap Motion sensor to detect and gather the gesture data, and feeds all of that information into LabVIEW. A Parrot AR Drone was chosen for this project because of a robust API that works well with this particular software suite. It seems as though a lot of the grunt work of recognizing gestures and sending commands to the drone are taken care of behind-the-scenes in software, so if you’re looking to do this on your own there’s likely to be quite a bit more work involved. That being said, it’s no small feat to get this to work in the first place and the video below is worth a view.

To some, gestures might seem like a novelty technology with no real applications, but they do have real-world uses for people with disabilities or others with unusual workflow that require a hands-free approach. So far we’ve seen hand gesture technologies that drive cars, help people get around in the physical world, and even play tetris.

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