Multi Input IR Remote Control Repeater


[Peter]‘s folks’ cable company is terrible – such a surprise for a cable TV provider – and the digital part of their cable subscription will only work with the company’s cable boxes. The cable company only rents the boxes with no option to buy them, and [Peter]‘s folks would need five of them for all the TVs in the house, even though they would only ever use two at the same time. Not wanting to waste money, [Peter] used coax splitters can take care of sending the output of one cable box to multiple TVs, but what about the remotes? For that, he developed an IR remote control multidrop extender. With a few small boards, he can run a receiver to any room in the house and send that back to a cable box, giving every TV in the house digital cable while still only renting a single cable box.

The receiver module uses the same type of IR module found in the cable box to decode the signals from the remote. With a few MOSFETs, this signal is fed over a three-position screw terminal to the transmitter module stationed right next to the cable box. This module uses a PIC12F microcontroller to take the signal input and translate it back into infrared.

[Peter]‘s system can be set up as a single receiver, and single transmitter, single receiver and multiple transmitter, many receivers to multiple transmitters, or just about any configuration you could imagine. The setup does require running a few wires through the walls of the house, but even that is much easier than whipping out the checkbook every month for the cable company.

Video below.

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Mining Bitcoins with Pencil and Paper


Right now there are thousands of computers connected to the Internet, dutifully calculating SHA-256 hashes and sending their results to other peers on the Bitcoin network. There’s a tremendous amount of computing power in this network, but [Ken] is doing it with a pencil and paper. Doing the math by hand isn’t exactly hard, but it does take an extraordinary amount of time; [Ken] can calculate about two-thirds of a hash per day.

The SHA-256 hash function used for Bitcoin isn’t really that hard to work out by hand. The problem, though, is that it takes a 64 byte value, sends it through an algorithm, and repeats that sixty-four times. There are a few 32-bit additions, but the rest of the work is just choosing the majority value in a set of three bits, rotating bits, and performing a mod 2.

Completing one round of a SHA-256 hash took [Ken] sixteen minutes and forty-five seconds. There are sixty-four steps in calculating the hash, this means a single hash would take about 18 hours to complete. Since Bitcoin uses a double SHA-256 algorithm, doing the calculations on a complete bitcoin block and submitting them to the network manually would take the better part of two days. If you’re only doing this as your daily 9-5, this is an entire weeks worth of work.

Just for fun, [Ken] tried to figure out how energy-efficient the bitcoin mining rig stored in his skull is. He can’t live on electricity, but donuts are a cheap source of calories, at about $0.23 per 200 kcalories. Assuming a metabolic rate of 1500 kcal/day, this means his energy cost is about 67 quadrillion times that of an ASIC miner.

Video below.

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Very Dumb Security For a WiFi Thermostat

elliot We have finally figured out what the Internet of Things actually is. It turns out, it’s just connecting a relay to the Internet. Not a bad idea if you’re building a smart, Internet-connected thermostat, but you have no idea how bad the security can be for some of these devices. The Heatmiser WiFi thermostat is probably the worst of the current round of smart home devices, allowing anyone with even a tiny amount of skill to control one of these thermostats over the Internet.

The Heatmiser is a fairly standard thermostat, able to connect to an 802.11b network and controllable through iOS, Android, and browser apps. Setting this up on your home network requires you to forward port 80 (for browser access) and port 8068 (for iOS/Android access). A username, password, and PIN is required to change the settings on the device, but the default credentials of user: admin, password: admin, and PIN: 1234 are allowed. If you’re on the same network as one of these devices, these credentials can be seen by looking at the source of the webpage hosted on the thermostat.

if you connect to this thermostat with a browser, you’re vulnerable to cross-site request forgery. If you use the Android or iOS apps to access the device with the custom protocol on port 8068, things are even worse: there is no rate limiting for the PIN, and with only four digits and no username required, it’s possible to unlock this thermostat by trying all 10,000 possible PINs in about an hour.

There are about a half-dozen more ways to bypass the security on the Heatmiser thermostat, but the most damning is the fact there is no way to update the firmware without renting a programmer from Heatmiser and taking the device apart. Combine this fact with the huge amount security holes, and you have tens of thousands of installed devices that will remain unpatched. Absolutely astonishing, but a great example of how not to build an Internet connected device.

A Nixie Clock with Neon Bulb Logic

nixie This is an oldie, but oh, man is this ever good. It’s a Nixie clock made without a microcontroller. In fact, there aren’t any logic chips in this circuit, either. As far as we can tell, the logic in this clock is made with resistors, diodes, caps, and neon tubes.

The design of this is covered in the creator’s webpage. This clock was inspired by a few circuits found in a 1967 book Electronic Counting Circuits by J.B. Dance. The theory of these circuits rely on the different voltages required to light a neon lamp (the striking voltage) versus the voltage required to stay lit (the maintaining voltage). If you’re exceptionally clever with some diodes and resistors, you can create a counting circuit with these lamps, and since it’s pretty easy to get the mains frequency, a neon logic clock starts looking like a relatively easy project.

This clock, like a lot of the author’s other work, is built dead bug style, and everything looks phenomenal. It looks like this clock is mounted to a plastic plate; a good thing, because something of this size would be very, very fragile.

Video below, thanks [jp] for sending this one in.

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About 30 years ago, before every computer had CD quality audio built in, audio cards and chips were technological marvels. MIDI chips, FM synthesis, and synths on a chip reigned supreme but one little device – just a handful of resistors – sounded fantastic. it was the Covox Speech Thing, a simple resistor ladder wired up to the parallel port of a computer that would output 8-bit audio to an external amplifier. [FK] recently built his own Covox (Czech, Google translatrix) with just 18 resistors, and the results sound fantastic.

Instead of fancy chips, the original Covox Speech Thing used the 8 bit parallel port on a PC. Back in the olden days, this was the fastest way to get digital data out of a computer, but since it was digital only, a DAC was required to turn this into audio. A simple resistor ladder was sufficient, and this hardware was eventually supported by the old DOS games from Sierra and Id.

[FK] has a demo of this LPT DAC available here, but we’re not thinking that link will last long. If anyone has a better link, leave a note in the comments and we’ll update this post. Thanks [beavel] for sending this in.

THP Semifinalist: OSHWatch


No, it’s not a finely crafted wrist accessory from Cupertino, but [Jared]‘s OSHWatch, but you’re actually able to build this watch thanks to an open design and reasonable, hand-solderable layout.

Built around a case found on DealExtreme that looks suspiciously similar to enclosures meant to hold an iPod Nano, [Jared]‘s smartwatch includes a 128×128 RGB OLED display, magnetometer, accelerometer, Bluetooth 4.0 transceiver, and a lithium-ion charger and regulator circuit. Everything is controlled with a PIC24, which should mean this watch has enough processing power to handle anything a watch should handle.

As for the UI and what this watch actually does [Jared] is repurposing a few Android graphics for this watch. Right now, the watch can display the time (natch), upcoming appointments on his schedule, accelerometer and magnetometer data, and debug data from the CPU. It’s very, very well put together, and repurposing an existing watch enclosure is a really slick idea. Videos below.

SpaceWrencherThe project featured in this post is a quarterfinalist in The Hackaday Prize.

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Hackaday Links: September 28, 2014


Kyocera is vastly expanding their product lineup with the Shop Sink 3530. The perfect addition to your copiers, fax machines, and laser printers.

About a year and a half ago and with objections from the editorial staff, we did a Top 10 hacking fails in movies and TV post. The number one fail is, “Stupid crime shows like NCIS, CSI, and Bones.” A new show on CBS just topped this list. It’s named Scorpion, and wow. Dropping a Cat5 cable from an airplane doing an almost-touch-and-go because something is wrong with the computers in the tower. Four million adults age 18-49 watched this.

thing[Derek] found something that really looks like the Hackaday logo in a spacer of some kind. It’s been sitting on his shelf for a few months, and is only now sending it in. He picked it up in a pile of scrap metal, and he (and we) really have no idea what this thing is. Any guesses?

[Sheldon] has a teardown of a vintage voltage and current standard. Just look at those hand drawn traces on a single sided board. Beautiful.

[Art] has another, ‘what is this thing’. He has two of them, and he’s pretty sure it’s some sort of differential, but other than that he’s got nothing. The only real clue is that [Art] lives near a harbor on the N. Cali coast. Maybe from a navigation system, or a governor from a weird diesel?

So you have a Kinect sitting on a shelf somewhere. That’s fine, we completely understand that. Here’s something: freeze yourself in carbonite. Yeah, it turns out having a depth sensor is exactly what you need to make a carbonite copy of yourself.


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