Playing The Interview Game

April 12, 2021 by Matthew Carlson 37 Comments

Technical interviews are generally dreaded, just like every other interview. However, technical interviews include many elements that non-technical folks might find mystifying or even pointless, such as whiteboard problem solving, take-home assignments, design sessions, or even just straight brain teasers. [Erik McClure] went a bit off the beaten path and started using the factory builder game Factorio as a technical interview.

Many point to the intent behind the problems and tricky questions inherent in whiteboard coding exercises and assert that the focus is not to complete the problem, but rather to expose how a candidate thinks and problem solves. Factorio is all problem-solving as you work as a team to slowly scale up a humble production line to a massive factory, which makes it a good candidate for assessing these sorts of skills. We doubt that the fine developers who wrote the game ever imagined it being used as an interview.

In all likelihood, you probably won’t have a Factorio interview anytime soon as [Erik] estimated each interview would take between eight and twenty hours. But we love the idea of reimagining the interview from a tedious set of problems to solve to an evolving cooperative game. Of course, you can also read more about getting the experience necessary for a job and what companies are looking for in an interview.

A trailer for Factorio is after the break.

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Color-Changing Sutures Detect Infection

April 4, 2021 by Kristina Panos 21 Comments

If you’ve ever had surgery, you know firsthand how important it is to keep the wound from getting infected. There are special conductive sutures that sense changes in wound status via electrical signal and relay the information to a computer or smart phone. As awesome as those sound, they’re a first-world solution that is far too pricey for places that need it most — developing countries. And surgical wounds in developing countries are about four times more likely to get infected than those in the US.

Iowa high-school student [Dasia Taylor] found a much simpler solution that could drive down the infection rate. She used beets to develop color-changing sutures that turn from bright red to purple within five minutes if an infection is present.

Beets, and other fruits and vegetables like blackberries, plums, and blueberries are natural indicators of pH. They have a compound called anthocyanin that gives them both their pigment and this cool property. Beets are perfect because they change color at a pH of nine — the same pH level of infected human skin, which is normally around five.

[Dasia] experimented with several types of suture thread to see which ones would absorb the beet juice in the first place. She settled on a cotton-polyester blend that is braided. While it probably helps absorb the beet juice, it would also give bacteria several places to hide. Another problem is that many surgeries involve cutting muscle, too, and by the time a deeper infection would show up on the sutures, it would be pretty late in the game. But if these color-changing sutures can be made to be cost-effective, safe for skin, and of course, keep wounds together, this solution is way better than nothing at all and definitely worth producing. You can see [Dasia] talk about her project in the video below.

Want to know more about natural pH indicators? Sure you do.

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A Few Of My Favorite Things: Pens

March 29, 2021 by Kristina Panos 111 Comments

Pens! They just might be the cheapest, most important piece of technology ever overlooked by a large group of people on a daily basis. Pens are everywhere from your desk to your car to your junk drawer, though they tend to blink out of existence when you need one. Where would we be without them? Probably still drawing on cave walls with dandelions and beets.

Photo of a Pilot Metropolitan by Aaron Burden on Unsplash

Why do I think pens are so great? Well, they’re a relatively cheap tool depending on the pen you get, but whatever you spend, you’re getting a lot for your money. Pens are possibility, pure and simple, and they’re even conveniently packaged in a portable device.

Aesthetically speaking, I like pens because of how different they can be both inside and out. Some of them make thick lines, some make thin lines, and in the case of flexible nibs, some alternate between thick and thin lines depending on pressure. I use pens for a number of reasons, most notably for writing. Everything you read here that bears my name began life as pen marks on paper.

Pens are revolutionary because they can be used to make ideas permanent and/or illustrate any concept. It’s up to you to use the pen wisely. You can use other, better tools later, but pens are always a great first tool. If you’re not encumbered by an uncomfortable grip, ink that skips, or a scratchy, draggy contact point, your ideas will flow more freely. When you find the right pen for you, you aren’t hindered by your tool — you’re elevated by it. Continue reading “A Few Of My Favorite Things: Pens” →

Negative Reinforcement: Drill Bits Edition

March 20, 2021 by Kristina Panos 21 Comments

In theory, it’s fun to have a lot of ~~toys~~ tools around, but the sad reality is that it’s only as fun as the organization level applied. Take it from someone who finds organization itself thrilling: it really doesn’t matter how many bits and bobs you have, as long as there’s a place for everything and you put away your toys at the end of the day.

[Cranktown City] is always leaving drill bits lying around instead of putting them back in their bit set boxes. Since he responds well to yelling, he decided to build an intelligent drill bit storage system that berates him if he takes one out and doesn’t put it back within ten minutes.

But [Cranktown City] did much more than that. The system is housed in a really nice DIY stand that supports his new milling and drilling machine and has space to hold a certain type of ubiquitous red tool box beneath the drill bits drawer.

All the bits now sit in a 3D-printed index that fits the width of the drawer. [Cranktown City] tried to use daisy-chained pairs of screws as contacts behind each bit that could tell whether the bit was home or not, but too much resistance interfered with the signal. He ended up using a tiny limit switch behind each bit instead. If any bit is removed, the input signal from the index goes low, and this triggers the Arduino Nano to do two things: it lights up a strip of red LEDs behind the beautiful cut out letters on the drawer’s lip, and it starts counting upward. Every ten minutes that one or more bits are missing, the drawer complains and issues ad hominem attacks. Check out the demo and build video after the break, but not until you put your tools away. (Have you learned nothing?)

Okay, so how do you deal with thousands of jumbled drill bits? Calipers and a Python script oughta do it.

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Our Curious Relationship With Caffeine

March 10, 2021 by Jenny List 109 Comments

If you were to paint a few stereotypes surrounding our community, where would you start? Maybe in apparel habits: the t-shirt from a tech conference, or the ubiquitous hoodie. Or how about leisure pursuits: gaming, or even D&D? There’s one thing I can think of that unites most of us, we have a curious affinity for caffeine. Is it a propensity for working into the dark of the night that’s responsible, or perhaps those of us with ADHD find the alertness helpful, but whatever it is we like our coffee and energy drinks. Rare is the hackerspace without a coffee machine and a fridge full of energy drinks, and I have lost count of the times I have been derided by the coffee cognoscenti among my peers for my being satisfied with a mug of mere instant. Deprived of my usual socialisation over the festive period by the pandemic, and contemplating my last bottle of Club-Mate as I drank it, I took a while to ponder on our relationship with this chemical.

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One Ring Light To Fool Them All Into Thinking You’re Well-Rested

March 8, 2021 by Kristina Panos 3 Comments

We know you’re beautiful, but maybe that cheap web camera from 2007 doesn’t always project your best image. Although web cameras are starting to come back down from the pandemic price gouging days, you could just build yourself a ring light and go from there, because better light may be all you need to look great.

Of course, this isn’t going to be cheaper than just buying a ring light, but if you already have a Circuit Playground and 3D printer lying around, you’re about halfway to owning one that’s much cooler than anything you can buy. The only other major hardware is the RGBW LED ring, the slide pots that adjust the light color, and the clicky little button that exits out of Zoom calls.

The business part is made to mount right over the camera, so the only part that has a footprint is the control box. No need to make space for a tripod or another boom. If you’re worried about staring into a bunch of lights, there’s a diffusing ring among the print files. We think this setup looks great, especially since [Southern Fried Science] built a light guide into the enclosure so those LED on the Circuit Playground don’t go to waste.

Do you just wish you had a more satisfying way to leave Zoom calls? If there’s a stud near your desk, it doesn’t get much more satisfying than a pull chain. If the only stud around is you, then use a giant mushroom button.

Via adafruit

Eyesight Guardian Polices Your Poor Pupils

March 5, 2021 by Kristina Panos 12 Comments

Don’t know about you, but over the last year or so, we have gone from spending ten or twelve hours a day at this computer to upwards of sixteen or eighteen. Fortunately there’s a window behind the monitor for taking those 20/20/20 breaks that are supposed to prevent eye strain, but it’s so hard to remember (and boring) to do it. And nobody needs yet another thing to remember in the name of self-care.

[Daniel Hingston] certainly agrees. As you’ll see in the delightful video after the break, [Daniel] has made a game out of the whole process of stopping every twenty minutes to spend twenty seconds looking at a point that’s at least twenty feet away. Once the break is over, [Daniel] uses the dual-purpose start button to acknowledge having looked away for 20 seconds. The device is meant to clip onto the corner of any monitor, and [Daniel] has provided several sizes of the bridge piece so that everyone can find their fit.

The Guardian’s guts are pretty simple — an Arduino Pro Mini runs the stop watch and a TFT display to show the graphics that live on an SD card. This is a great way to preserve your eyesight by gamifying something we all know we should be doing. It might be nice to add a break timer that counts up to 25 or thereabouts so you have time to stand up and come back. If you press the button too soon, it scolds you and you have to start your eye break over.

Need some more self-care lately? Our own [Jenny List] has your back in these interesting times.

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