Mirror Turns Webcam Into Document Camera

September 17, 2020 by Elliot Williams 12 Comments

This is one of those so-simple-I-wish-I-invented-it hacks. Professor [Michael Peshkin] is teaching his engineering students remotely. While he has a nice second camera that he can use to transmit whatever he doodles on paper, most of his students just have the single webcam built into their laptops.

The solution is to put a mirror in front of the laptop cam, and flip the image left-to-right in software. They use Zoom, which has a mirror mode. Done.

The trick is making a nice frame. [Michael] has bent one out of wire, but suggests that a mirror compact works about as well in a pinch. It’s super important that his students can ask him questions backed up by drawings, and this reduces the startup cost to nearly nothing, making it universally useful.

[Prof. Peshkin] is not a stranger to mirror-based pedagogical hacks. Seven years ago, he showed us how to make a transparent whiteboard for video lectures, and it blew up on Hackaday. Since then, there are hundreds or thousands of Lightboards in the wild. We hope this idea catches on as well!

This LEGO Air Conditioner Is Cooler Than Yours

September 13, 2020 by Kristina Panos 26 Comments

What’s the coolest thing a person can build with LEGO? Well it’s gotta be an air conditioner, right? Technically, [Manoj Nathwani] built a LEGO-fied swamp cooler, but it’s been too hot in London to argue the difference.

This thoroughly modular design uses an Arduino Uno and a relay module to drive four submersible pumps. The pumps are mounted on a LEGO base and sunk into a tub filled with water and ice packs. In the middle of the water lines are lengths of copper tubing that carry it past four 120mm PC case fans to spread the coolness. It works well, it’s quiet, and it was cheap to build. Doesn’t get much cooler than that.

[Manoj] had to do a bit of clever coupling to keep the tubing transitions from leaking. All it took was a bit of electrical tape to add girth to the copper tubes, and a zip tie used as a little hose clamp.

We think the LEGO part of this build looks great. [Manoj] says they did it by the seat of their pants, and lucked out because the copper and plastic tubing both route perfectly through the space of a 1x1x1 brick.

DIY cooling can take many forms. It really just depends what kind of building blocks you have at your disposal. We’ve even seen an A/C built from a water heater.

Don’t Slack Off On Updating Your Status

September 2, 2020 by Kristina Panos 16 Comments

Displaying an accurate status in Slack (or whatever other employer-provided collaboration program you may be forced to run) is crucial in 2020. If you need to make a sandwich or take the dog out real quick, but you don’t update your status to show yourself as away, you might come back to a string of increasingly concerned or frustrated messages with lots of annoying question marks and the occasional interrobang.

[Becky Stern] decided that a physical interface would be a far more fun way to keep tabs on her status, and an excellent visual reminder to actually do it. We totally agree. Inside the box is a NodeMCU which is using [Brian Lough]’s Slack API library for Arduino. This made it easy for [Becky] to create a switch/case selector of statuses, and in each of these she can set the presence token as auto or away, and show a custom message with an appropriate emoji. These of course match the emoji semi-circling the selector, which is a rotary switch with a really nice knob.

While we’re on the subject of Slack notifiers, how about a companion cat to wave when you’ve been mentioned?

Continue reading “Don’t Slack Off On Updating Your Status” →

Four Years Later, Off-Grid Office Shed Still Rocks

August 21, 2020 by Donald Papp 25 Comments

About four years ago, [Russell Graves] created what was, to him, the ultimate work-from-home environment: an off-grid office shed. The shed might look a bit small, but it’s a considerably larger workspace than most people in an office are granted. Four years later, in the middle of a global pandemic, working from home has become much more common and [Russel] shares some thoughts on working from home and specifically reflects on how his off-grid, solar powered shed office (or “shoffice” as he likes to call it) has worked out. In short, after four years, it rocks hard and is everything he wanted and more.

Its well-insulated plywood walls let him mount monitor arms and just about anything else anywhere he wants, and the solar power system allows him to work all day (and into the night if he wants, which he doesn’t) except for a few spells in the winter where sunlight is just too scarce and a generator picks up the slack. Most importantly, it provides a solid work-life separation — something [Russell] is convinced is critical to basic wellness as a human being.

That’s not to say an off-grid solar shed is the perfect solution for everyone. Not everyone can work from home, but for those who can and who identify with at least some of the motivations [Russell] expressed when we covered how he originally created his office shed, he encourages giving it some serious thought.

The only thing he doesn’t categorically recommend is the off-grid, solar powered part. To be clear, [Russell] is perfectly happy with his setup and even delights in being off-grid, but admits that unless one has a particular interest in solar power, it makes more sense to simply plug a shed office into the grid like any other structure. Solar power might seem like a magic bullet, but four years of experience has taught him that it really does require a lot of work and maintenance. Determined to go solar? Maybe give the solar intensity sensor a look, and find out just how well your location is suited to solar before taking the plunge.

Mixing Up Your Own Supersized Sidewalk Chalk

August 20, 2020 by Brian McEvoy 12 Comments

When folks started quarantining, chalk art spilled onto driveways and sidewalks to remind us that there’s still beauty and creative people doing what they always do. Now it’s time to strut your stuff and show your neighbors that things are greener on your slab of concrete. [friedpotatoes] has shared their giant sidewalk recipe with the world so you can paint the town red. With chalk.

Name brand sidewalk chalk is expensive considering how easy it is to make. What Big Chalk doesn’t want you to know is that the ingredients are just water, plaster of Paris, and tempera paint; meaning this project should be safe enough for the junior hackers to get some hands-on time. Some folks use food coloring instead of paint, but we know what happens to clothing when kids get their mitts on food coloring. [friedpotatoes] also includes extensive repurposing of recyclables, which is commendable.

The instructions suggest filling potato chip (crisp) tubes through a milk jug funnel to make giant pieces, but you can use any mold you like. If you have a CNC machine, it should be no trouble to make stamp-like pieces of chalk for tagging on the go, or shapes like arrows when you have to direct a miniature parade.

For permanent and precise sidewalk decorations, you can check out a graffiti paint machine and for totally temporary messages there is a water-dispensing writer.

Encouragement Machine Battles Your Inner Bully

August 18, 2020 by Kristina Panos 1 Comment

We would be preaching to the choir if we told you that fear is the action killer when it comes to the challenge of new projects in uncharted territory. Everyone who reads Hackaday knows that it takes mettle to forge through the self-doubt as we push ourselves to new engineering heights.

[JBV Creative] hears the voice, too: the one that says you can’t build that thing, it’s too difficult/useless. He knows that both creativity and anti-creativity stem from the same source — the powerful human mind that dreams up these projects in the first place.

The Encouragement Machine combines the two in a piece that engineers art from garbage, aka negative thoughts. It works by first acknowledging the most basal of discouraging thoughts — an important step of the process — and then it simply trims away the negativity.

This machine uses a stepper motor to feed receipt paper underneath a custom stamp that says YOU CAN’T DO IT. Then it passes the paper through a pair of servo-driven scissors that snip off the apostrophe-t.

Ironically or not, [JBV Creative] ran into a few issues with this build, but managed to muster up enough moxie to work through the problems without encouraging slips of paper. We have to wonder how much more smoothly the next project will go given all the positivity he now has on-demand.

[JBV] doesn’t delve into the electronics much, but it looks like an Arduino and a motor driver to us. We totally dig the design — it looks like an electrical substation or rocket launch pad that happens to have a Ferris wheel. Step right up and check out the build video after the break.

Generic encouragement is great all-purpose attitude adjuster, but what if you want more specific sentiments? Here’s an affirmation mirror that will help you believe whatever you program into the scrolling display.

Continue reading “Encouragement Machine Battles Your Inner Bully” →

Helmet Decal Charger Keeps Them Ready To Glow

August 15, 2020 by Kristina Panos 9 Comments

When firefighters are battling a blaze, it’s difficult for them to find each other in the smoky darkness. To help stand out they wear glow-in-the-dark decals on their helmets, but since they spend so much of their down time stowed away in a dark locker, they don’t always have a chance to charge up.

[Bin Sun]’s firefighter friend inspired them to build a portable charging system that can stuff those helmet decals full of photons in a matter of minutes. Although phosphorescent materials will charge in any light, they charge the fastest with ultraviolet light. This uses a pair of UV LED strips controlled by an off-the-shelf programmable timer, and powered with an 18-volt drill battery stepped down to 12 V. The timer makes it easy for [Bin Sun]’s friend to schedule charge times around their shifts, so the battery lasts as long as possible while keeping the decals ready to glow.

We love that [Bin Sun] seems to have thought of everything. The light strips are nestled into 3D-printed holders that also house small magnets. This makes it easy to position the lights on either side of the locker so both the front and back decals soak up the light.

Phosphorescent materials are great as a reusable display medium, especially when they’re designed to look like Nixie tubes.