This Bitcoin Price Tracking Traffic Light Isn’t Just A Red LED

Quick, what’s the price of Bitcoin? Is it lower today than yesterday? Are you overdrafting your Lamborghini account? What if you had an easy way to tell at a glance how much you could have made if you sold in December of last year? That’s what this Bitcoin price tracking traffic light is all about, and it’s a great use of existing electronics.

The hardware for this build is a traffic light table lamp available on Amazon for twenty bucks. Inside this traffic light, you get a PCB with three LEDs and a small microcontroller to control the LEDs. The microcontroller isn’t used in this case, instead the microcontroller is removed and a few wires are soldered up to the base of the transistors used to drive the LEDs. The other ends of these wires are attached to a trio of pins on a Raspberry Pi Zero W, giving this traffic light table lamp Linux and a connection to the Internet.

On the software side of things, we’re looking at a Docker container running a Python script that fetches the latest Bitcoin price from Coindesk and calculates the change from the previous fetch of the price of Bitcoin. This data is shuffled off to another Python script that actually changes the LEDs on the lamp.

Sure, these days a ‘bitcoin price tracking traffic light’ is as simple as connecting a red LED to a battery, and if you’re feeling extra fancy you can add a 220 Ω resistor. But this is a project that’s so well executed that we’ve got to give it a tip ‘o our hat.

Bitcoin’s Double Spending Flaw Was Hush-Hush During Rollout

For a little while it was possible to spend Bitcoin twice. Think of it like a coin on a string, you put it into the vending machine to get a delicious snack, but if you pull the string quickly enough you could spend it again on some soda too. Except this coin is worth something like eighty-grand.

On September 20, the full details of the latest fix for the Bitcoin Core were published. This information came two days after the fix was actually released. Two vulnerabilities were involved; a Denial of Service vulnerability and a critical inflation vulnerability, both covered in CVE-2018-17144. These were originally reported to several developers working on Bitcoin Core, as well as projects supporting other cryptocurrencies, including ABC and Unlimited.

Let’s take a look at how this worked, and how the network was patched (while being kept quiet) to close up this vulnerability.

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A Close Eye on Power Exposes Private Keys

Hardware wallets are devices used exclusively to store the highly sensitive cryptographic information that authenticates cryptocurrency transactions. They are useful if one is worried about the compromise of a general purpose computer leading to the loss of such secrets (and thus loss of the funds the secrets identify). The idea is to move the critical data away from a more vulnerable network-connected machine and onto a device without a network connection that is unable to run other software. When designing a security focused hardware devices like hardware wallets it’s important to consider what threats need to be protected against. More sophisticated threats warrant more sophisticated defenses and at the extreme end these precautions can become highly involved. In 2015 when [Jochen] took a look around his TREZOR hardware wallet he discovered that maybe all the precautions hadn’t been considered.

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Accessing Blockchain on ESP8266 Using the NodeMCU Board

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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What Does ‘Crypto’ Actually Mean?

This article is about crypto. It’s in the title, and the first sentence, yet the topic still remains hidden.

At Hackaday, we are deeply concerned with language. Part of this is the fact that we are a purely text-based publication, yes, but a better reason is right there in the masthead. This is Hackaday, and for more than a decade, we have countered to the notion that ‘hackers’ are only bad actors. We have railed against co-opted language for our entire existence, and our more successful stories are entirely about the use and abuse of language.

Part of this is due to the nature of the Internet. Pedantry is an acceptable substitute for wisdom, it seems, and choosing the right word isn’t just a matter of semantics — it’s a compiler error. The wrong word shuts down all discussion. Use the phrase, ‘fused deposition modeling’ when describing a filament-based 3D printer, and some will inevitably reach for their pitchforks and torches; the correct phrase is, ‘fused filament fabrication’, the term preferred by the RepRap community because it is legally unencumbered by patents. That’s actually a neat tidbit, but the phrase describing a technology is covered by a trademark, and not by a patent.

The technical side of the Internet, or at least the subpopulation concerned about backdoors, 0-days, and commitments to hodl, is now at a semantic crossroads. ‘Crypto’ is starting to mean ‘cryptocurrency’. The netsec and technology-minded populations of the Internet are now deeply concerned over language. Cryptocurrency enthusiasts have usurped the word ‘crypto’, and the folks that were hacking around with DES thirty years ago aren’t happy. A DH key exchange has nothing to do with virtual cats bought with Etherium, and there’s no way anyone losing money to ICO scams could come up with an encryption protocol as elegant as ROT-13.

But language changes. Now, cryptographers are dealing with the same problem hackers had in the 90s, and this time there’s nothing as cool as rollerblading into the Gibson to fall back on. Does ‘crypto’ mean ‘cryptography’, or does ‘crypto’ mean cryptocurrency? If frequency of usage determines the correct definition, a quick perusal of the press releases in my email quickly reveals a winner. It’s cryptocurrency by a mile. However, cryptography has been around much, much longer than cryptocurrency. What’s the right definition of ‘crypto’? Does it mean cryptography, or does it mean cryptocurrency?

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Stretched PC Case Turned GPU Cryptominer

We don’t do financial planning here at Hackaday, so we won’t weigh in on the viability of making money mining cryptocurrency in such a volatile market. But we will say that if you’re going to build a machine to hammer away at generating Magical Internet Monies, you might as well make it cool. Even if you don’t turn a profit, at least you’ll have something interesting to look at while you weep over your electricity bill.

Sick of seeing the desktop machine he built a decade ago gathering dust, [plaggle24w5] decided to use it as the base for a cryptocurrency mining rig. Of course, none of the original internals would do him any good, but the case itself ended up being a useful base to expand on. With the addition of some 3D printed components, he stretched out the case and installed an array of video cards.

To start with, all the original plastic was ripped off, leaving just the bare steel case. He then jammed a second power supply into the original optical drive bays to provide the extra power those thirsty GPUs would soon be sucking down. He then designed some 3D printed arms which would push out the side panel of the case far enough that he could mount the video cards vertically alongside the case. Three case fans were then added to the bottom to blow air through the cards.

While [plaggle24w5] mentions this arrangement does work with the case standing up, there’s obviously not a lot of air getting to the fans on the bottom when they’re only an inch or so off the ground. Turning the case on its side, with the motherboard parallel to the floor, allows for much better airflow and results in a measurable dip in operating temperature. Just hope you never drop anything down onto the exposed motherboard…

Mining Bitcoin on desktop computers might be a distant memory, but the latest crop of cryptocurrencies are (for now) giving new players a chance to relive those heady early days.

Hackaday Links: February 11, 2018

Are you a student? Are you part of a hackerspace? We have a contest going on right now where you can win a fancy new Prusa i3 MK3. The Repairs You Can Print contest is a challenge to do something useful with that machine that spits out tugboats. We’re looking for functional repairs of items around your house, office, or garage. Did you repair something with a 3D printer? Then you too can get in on the action! Enter now! Check out the entries!

You may know Flite Test as the group who do everything surrounding remote control flight (mostly fixed wings, a nice counter to the quadification of the hobby over the last few years). Flite Test designs and sells airplanes made out of Dollar Tree foam board, they have yearly, bi-coastal meetups, and they’re all-around awesome dudes. Now, they want to build the Disneyland of RC flight. [Josh Bixler], the face of Flite Test and a guy who has a plane named after him, wants to buy a golf course and turn it into the world’s best RC flying park, with a ~2000 foot grass strip for general aviation. We’re looking at their crowdfunding campaign, and it looks promising it might be funded by the time this goes live.

A while ago, [Peter Jansen], the guy who built a tricorder and a laser-cut CT scanner, made a magnetic camera. This Hall Effect camera is a camera for magnetism instead of light. Now, this camera has been fully built and vastly improved. He’s capturing ‘frames’ of magnetism in a spinning fan at 2000 Hz (or FPS, terminology kind of breaks down here), and it’s beautiful.

Oh thank God we can finally buy GPUs again. Try buying them with Bitcoin.

In the last few years, CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora, has expanded. Originally, this was one of the treaties that banned the import or export of rhino horn, but recently this expanded to the export of rosewood thanks to increased demand in China for rosewood furniture. The laws of unintended consequences kicked into effect, and importing anything made out of rosewood is now a mess of permits and inspections at the border, including musical instruments. Travelling orchestras, for example, are at risk of having their string section confiscated because of rosewood tuning pegs. Cooler minds may now be prevailing, and there’s some hope the regulations may be changed during the next meeting of the CITES convention next year.

As noted a few months ago, there was a possibility of Broadcom buying Qualcomm for one… hundred… Billion dollarsThis offer was rejected, with Qualcomm saying the offer wasn’t high enough. Broadcom fired back with an offer of $82 per share, or $121B. This offer was rejected this week.

Need some EMC testing? [Zach]’s got your back. He’s reserved some time in a 10m EMC chamber for testing NeuroBytes this week. If you have an Open Source project that needs a pre-test scan for unintentional radiator, you can get in on the action. This is just a pre-test, you’re not getting certification, and you’re not going to test anything with radios, and you need to ship [Zach] your stuff. But still, free test time. Woo.