DIY Trommel Sifts Compost In Style

January 2, 2020 by 22 Comments

Composting is a great idea that helps you and the planet at the same time. But all that stuff is going to break down at different rates, and depending on what you put in there and how soon you want to use the compost, you’ll probably have to sift out some unwanted stuff first.

[Minnear Knives] had a bunch of apricot stones in his compost pile, and it was the pits. He did some research and decided to build his own rotary trommel to tumble out the trash. As you will see in the video after the break, it works really well. All he has to do is turn on the motor and shovel raw compost or dirt into one end. Bad stuff tumbles out the other end into a wheelbarrow, while the good stuff is sifted down into a pile under the cylinder. Just look at that rich, fluffy compost.

The best part is that he was able to make it mostly from stuff he had lying around, though he did trade some beer for the v-belt pulley. The cylinder is essentially made from mesh that’s zip-tied to bicycle rims. A 1/4 horsepower motor mounted up top uses that v-belt pulley to spin the cylinder’s rims against casters that are mounted to the frame. Thanks to the pair of bike wheels on the back, he can cart it around the ranch unassisted.

Composting doesn’t have to be any more difficult than a pile in the backyard. But if you don’t have a backyard, why not build a rotating bin that you can monitor from your phone?

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Assistive Technolgy Switch Is Actuated Using Your Ear Muscles

January 2, 2020 by 16 Comments

Assistive technology is extremely fertile ground for hackers to make a difference, because of the unique requirements of each user and the high costs of commercial solutions. [Nick] has been working on Earswitch, an innovative assistive tech switch that can be actuated using voluntary movement of the middle ear muscle.

Most people don’t know they can contract their middle ear muscle, technically called the tensor tympani, but will recognise it as a rumbling sound or muffling effect of your hearing when yawning or tightly closing eyes. Its function is actually to protect your hearing from loud sounds screaming or chewing. [Nick] ran a survey and found that 75% can consciously contract the tensor tympani and 17% of can do it in isolation from other movements. Using a cheap USB auroscope (an ear camera like the one [Jenny] reviewed in November), he was able to detect the movement using iSpy, an open source software package meant for video surveillance. The output from iSpy is used to control Grid3, a commercial assistive technology software package. [Nick] also envisions the technology being used as a control interface for consumer electronics via earphones.

With the proof of concept done, [Nick] is looking at ways to make the tech more practical to actually use, possibly with a CMOS camera module inside a standard noise canceling headphones. Simpler optical sensors like reflectance or time-of-flight are also options being investigated. If you have suggestions for or possible use case, drop by on the project page.

Assistive tech always makes for interesting hacks. We recently saw a robotic arm that helps people feed themselves, and the 2017 Hackaday Prize has an entire stage that was focused on assistive technology.

Tony Brooker And Autocode – The First High-level Language

January 2, 2020 by 32 Comments

The field of computer science has undeniably changed the world for virtually every single person by now. Certainly for you as Hackaday reader, but also for everyone around you, whether they’re working in the field themselves, or are simply enjoying the fruits of convenience it bears. What was once a highly specialized niche field for a few chosen people has since grown into a discipline that not only created one of the biggest industry in modern times, but also revolutionized every other industry, some a few times over.

The fascinating part about all this is the relatively short time span it took to get here, and with that the privilege to live in an era where some of the pioneers and innovators, the proverbial giants whose shoulders every one of us is standing on, are still among us. Sadly, one of them, [Tony Brooker], a pioneer of the early programming language concept known as Autocode, passed away in November. Reaching the remarkable age of 94, the truly sad part however is that this might be the first time you hear his name, and there’s a fair chance you never heard of Autocode either.

But Autocode was probably the first high-level computer language, and as such played a fundamental role in the development of whatever you’re coding in today. So to honor the memory of [Tony Brooker], let’s remember the work he did with Autocode, and the leap in computer science history that it represented.

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Tales (and Advice) From Setting Up A Product Line

January 2, 2020 by 5 Comments

Making something that has to get into others’ hands involves solving a lot of different problems, many of which have nothing at all to do with actually building the dang things. [Conor Patrick] encountered them when he ran a successful Kickstarter campaign for an open-source USB security key that was not only shipped to backers, but also made available as an ongoing product for sale. There was a lot of manual and tedious work that could have been avoided, and so [Conor] laid out all the things he wishes he had done when first setting up a product line.

Turning these unprogrammed boards into finished products then shipping them is a big job.

If the whole process is a river, then the more “upstream” an issue is, the bigger its potential impact on everything that comes afterwards. One example is the product itself: the simplest and most easily managed product line is one that has only one product with no variations. That not only minimizes errors but makes supply, production, and shipping more straightforward. Striving for a minimum number of products and variations is also an example of something [Conor] didn’t do. In their crowdfunding campaign they offered the SoloKeys USB device — an implementation of the FIDO2 authentication token — as either USB-A or USB-C. There were also two types of key: NFC-capable (for tapping to a smartphone) and USB only. That is four products so far.

Offering keys in an unlocked state for those who want to tamper makes it eight different products. On top of that, they offered color choices which not only adds complexity to production, but also makes it harder to keep track of what everyone ordered. [Conor] also observed that the Kickstarter platform and back end are really not set up like a store, and it is clunky at best to try to offer (and manage) different products and variations from within it.

Another major point is fulfillment and in [Conor]’s opinion, unless the quantities are small, an order fulfillment company is worth partnering with. He says there are a lot of such companies out there, and it can be very time consuming to find the right one, but it will be nothing compared to the time and effort needed to handle, package, address, and ship several hundreds (or thousands!) of orders personally. His team did their own fulfillment for a total of over 2000 units, and found it a long and tedious process filled with hidden costs and challenges.

There’s good advice and background in [Conor]’s writeup, and this isn’t his first rodeo. He also shared his thoughts on taking electronics from design to production and the more general advice remains the same for it all: be honest and be open. Under-promise and over-deliver, especially when it comes to time estimates.

Ask Hackaday: How Do You Keep The 3D Printer From Becoming EWaste

January 2, 2020 by 94 Comments

One thing we sometimes forget in our community is that many of the tecniques and machines that we take for granted are still something close to black magic for many outsiders. Here’s a tip: leave a 3D printer running next time you take a group of visitors round a hackerspace, and watch their reaction as a Benchy slowly emerges from the moving extruder. To us it’s part of the scenery, but to them it’s impossibly futuristic and their minds are blown.

Just because something says it's a Prusa i3, doesn't mean it is a Prusa i3.
Just because something says it’s a Prusa i3, doesn’t mean it is a Prusa i3.

Nearly 15 years after the dawn of the RepRap project we have seen a huge advancement in the capabilities of affordable 3D printers, and now a relatively low three-figure sum will secure a machine from China that will churn out prints whose quality would amaze those early builders. We’ve reached the point in our community at which many people are on their third or fourth printer, and this has brought with it an unexpected side-effect. Where once a hackerspace might have had a single highly prized 3D printer, now it’s not unusual to find a pile of surplus older printers on a shelf. My hackerspaces both have several, and it’s a sight I’ve frequently seen on my travels around others. Perhaps it’s a sign of a technology maturing when it becomes ewaste, and thus it seems affordable 3D printing has matured. Continue reading “Ask Hackaday: How Do You Keep The 3D Printer From Becoming EWaste” →

Unlocking SIM Cards With A Logic Analyzer

January 2, 2020 by 20 Comments

[Jason Gin] wanted to reuse the SIM card that came with a ZTE WF721 wireless terminal he got from AT&T, but as he expected, it was locked to the device. Unfortunately, the terminal has no function to change the PIN and none of the defaults he tried seemed to work. The only thing left to do was crack it open and sniff the PIN with a logic analyzer.

This project is a fantastic example of the kind of reverse engineering you can pull off with even a cheap logic analyzer and a keen eye, but also perfectly illustrates the fact that having physical access to a device largely negates any security measures the manufacturer tries to implement. [Jason] already knew what the SIM unlock command would look like; he just needed to capture the exchange between the WF721 and SIM card, find the correct byte sequence, and look at the bytes directly after it.

Finding the test pads on the rear of the SIM slot, he wired his DSLogic Plus logic analyzer up to the VCC, CLK, RST, and I/O pins, then found a convenient place to attach his ground wire. After a bit of fiddling, he determined the SIM card was being run at 4 MHz, so he needed to configure a baud rate of 250 kbit/s to read the UART messages passing between the devices.

Once he found the bytes that signified successful unlocking, he was able to work his way backwards and determine the unlock command and its PIN code. It turns out the PIN was even being sent over the wire in plain text, though with the way security is often handled these days, we can’t say it surprises us. All [Jason] had to do then was put the SIM in his phone and punch in the sniffed PIN when prompted.

Could [Jason] have just run out to the store and picked up a prepaid SIM instead of cracking open this wireless terminal and sniffing its communications with a logic analyzer? Of course. But where’s the fun in that?

Roll The Bones Chernobyl Style

January 2, 2020 by 18 Comments

We’re suckers for the Fallout aesthetic, so anything with a post-apocalyptic vibe is sure to get our attention. With a mid-century look, Nixie tubes, a brushed metal faceplate, and just a touch of radioactivity, this quantum random number generator pushes a lot of design buttons, and it pushes them hard.

Charmingly named “Chernobyl Dice”, this little gadget comes to us from [Nathan Griffith], and appears to be one of those “Why not?” builds we love so much. The heart of any random number generator is a source of entropy, for which [Nathan] chose to use six slightly radioactive uranium glass marbles. Those feature prominently in the front panel of the device, occasionally made to fluoresce with a few UV LEDs just because it looks cool. A Geiger tube inside the case is used to look for decay events from the marbles every millisecond. After some adjustment for the bias toward zeroes due to the relative rarity of decay events, the accumulated bits are displayed on eight Nixies. The box can be set to generate a stream of random numbers up to 31 bits long and send it over a USB port, or make random throws of a die with a settable number of sides. And when it’s not doing random stuff, it can just be a cool Nixie clock.

There are lots of ways to generate the entropy needed for truly random number generation, from a wall of lava lamps to bubbles in a fish tank. They’ve all got style, but something about this one just works.

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