[u407]’s 3D printed Signspinner was created as a clean/dirty indicator for a dishwasher, and at its heart is a mechanism that works a lot like that of a retractable ballpoint pen. Every click of the plunger spins the circular label inside by one-quarter of a rotation. In [u407]’s case it only needs to alternate between showing “clean” and “dirty”, but there are in fact four total label positions.
The entire mechanism including the spring is 3D printed, but the spring is PETG and the rest is PLA. [u407] doubts PLA would work for the spring because of how much it gets compressed, but suggests that ABS might work as an alternative.
If you’re having trouble visualizing how this mechanism works, we covered [Bill Hammack] explaining exactly how retractable ballpoint pens work which should make it perfectly clear. It’s fundamentally the same principle.
Somehow [hvde] wound up with a CB radio that does AM and SSB on the 11 meter band. The problem was that the radio isn’t legal where he lives. So he decided to change the radio over to work on the 6 meter band, instead.
We were a little surprised to hear this at first. Most radio circuits are tuned to pretty close tolerances and going from 27 MHz to 50 MHz seemed like quite a leap. The answer? An Arduino and a few other choice pieces of circuitry.
Continue reading “CB Radio + Arduino = 6 Meter Ham Band”
If you treat your Pi as a wearable or a tablet, you will already have a battery. If you treat your Pi as a desktop you will already have a plug-in power supply, but how about if you live where mains power is unreliable? Like [jwhart1], you may consider building an uninterruptible power supply into a USB cable. UPSs became a staple of office workers when one-too-many IT headaches were traced back to power outages. The idea is that a battery will keep your computer running while the power gets its legs back. In the case of a commercial UPS, most generate an AC waveform which your computer’s power supply converts it back to DC, but if you can create the right DC voltage right to the board, you skip the inverting and converting steps.
Cheap batteries develop a memory if they’re drained often, but if you have enough space consider supercapacitors which can take that abuse. They have a lower energy density rating than lithium batteries, but that should not be an issue for short power losses. According to [jwhart1], this quick-and-dirty approach will power a full-sized Pi, keyboard, and mouse for over a minute. If power is restored, you get to keep on trucking. If your power doesn’t come back, you have time to save your work and shut down. Spending an afternoon on a power cable could save a weekend’s worth of work, not a bad time-gamble.
We see what a supercap UPS looks like, but what about one built into a lightbulb or a feature-rich programmable UPS?
If there’s one thing any cat will work for, it’s food. Usually, this just consists of meowing and/or standing on your chest until you give up the goods. [DynamicallyInvokable] has a beautiful cat, Emma, who meows loudly for food at obscene hours of the morning. As she ages, it’s getting harder and more important to control her weight. Clearly, it was time to build the ultimate automatic cat feeder—one that allows him to get lazy while at the same time getting smart about Emma’s weight.
After a year and a half of work, the feeder is complete. Not only does it deliver the goods several times a day, it sends a heap of data to the cloud about Emma’s eating habits. There’s a scale built into the platform, and another in the food bowl. Together, they provide metrics galore that get automatically uploaded to AWS. Everything is controlled with an ESP32 Arduino, including a rainbow of WS2812s that chases its tail around the base of the feeder. The faster it goes, the closer it is to feeding time.
The best part about this unique feeder is that nearly every piece is 3D printed, including the gears. Be sure to check out the build gallery, where you can watch it come together piece by piece. Oh, and claw your way past the break to see Emma get fed.
Emma doesn’t have to worry about sharing her food. If she did, maybe [DynamicallyInvokable] could use facial recognition to meet the needs of multiple cats.
Continue reading “Cat Feeder Adds Metrics To Meow Mix”
Join us on Wednesday, August 7th at noon Pacific for the Kickstarter Hack Chat with Beau Ambur and Clarissa Redwine!
For many of us, magic things happen on our benches. We mix a little of this, one of those, and a couple of the other things, and suddenly the world has the Next Big Thing. Or does it? Will it ever see the light of day? Will you ever build a community around your project so that the magic can escape the shop and survive the harsh light of the marketplace? And perhaps most importantly, will you be able to afford to bring your project to market?
Crowdfunding is often the answer to these questions and more, and Kickstarter is one of the places where hackers can turn their project into a product. Beau and Clarissa, both outreach leads for the crowdfunding company, will stop by the Hack Chat to answer all your questions about getting your project off the bench and into the marketplace. Join us as we discuss everything from building a community that’s passionate enough about your idea to fund it, to the right way to share your design story.
Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, August 7 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.
Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.
You’ve probably seen multicolored flashing LEDs embedded into clear plastic cups or coasters before, they’re quite commonly used in fancy restaurants that also feature animatronic characters and a gift shop on the way out. But have you ever wondered about the logistics of maintaining such devices? When the anthropomorphic rodent shuts down for the night, you’re going to want to clean all those blinking doodads; but any opening to connect a charger or insert a battery is just a leak waiting to happen.
[Scott Clandinin] has come up with a solution to this problem that’s equal parts brilliant simplicity and unabashed overengineering. Using wireless charging and supercapacitors, he’s developing an LED coaster that can be hermetically sealed in clear resin.
With no plugs to connect or batteries to change, these coasters can be permanently encapsulated with no ill effects. Granted the supercapacitors will degrade with time and eventually won’t hold a charge for as long, but even the most conservative estimates would have these coasters still partying in a decade.
For his prototype version [Scott] has put together a simple charging base, but we imagine in a full deployment such devices could be charged with induction coils built into a bar or table. While the energy consumption could potentially be a showstopper, we’d love to see a future version that integrates a radio receiver. Then the coasters could double as pagers to let diners know their table is ready.
While this device is obviously much thicker than a traditional coaster, it looks fairly reasonable even at this early stage. We like the concentric design that puts the coil inside the PCB, and wonder if similar cutouts couldn’t be used to get the twin 15F supercapacitors and charging module hunkered down just a few millimeters more. The 2019 Hackaday Prize is all about evolving an idea into a design suitable for production, and those are the sort of incremental improvements that the judges will certainly be keeping an eye out for.
When the SpaceX Dragon spacecraft reached orbit for the first time in 2010, it was a historic achievement. But to qualify for NASA’s Commercial Orbital Transportation Services (COTS) program, the capsule also needed to demonstrate that it could return safely to Earth. Its predecessor, the Space Shuttle, had wings that let it glide home and land like a plane. But in returning to the classic capsule design of earlier spacecraft, SpaceX was forced to rely on a technique not used by American spacecraft since the 1970s: parachutes and an ocean splashdown.
The Dragon’s descent under parachute, splashdown, and subsequent successful recovery paved the way for SpaceX to begin a series of resupply missions to the International Space Station that continue to this day. But not everyone at SpaceX was satisfied with their 21st century spacecraft having to perform such an anachronistic landing. At a post-mission press conference, CEO Elon Musk told those in attendance that eventually the Dragon would be able to make a pinpoint touchdown using thrusters and deployable landing gear:
The architecture that you observed today is obviously similar to what was employed in the Apollo era, but the next generation Dragon, the Crew Dragon, we’re actually going to be aiming for a propulsive landing with gear. We’ll still have the parachutes as a backup, but it’s going to be a precision landing, you could literally land on something the size of a helipad propulsively with gear, refuel, and take off again.
But just shy of a decade later, the violent explosion of the first space worthy Crew Dragon has become the final nail in the coffin for Elon’s dream of manned space capsules landing like helicopters. In truth, the future of this particular capability was already looking quite dim given NASA’s preference for a more pragmatic approach to returning their astronauts from space. But Crew Dragon design changes slated to be implemented in light of findings made during the accident report will all but completely remove the possibility of Dragon ever performing a propulsive landing.
Continue reading “SpaceX Clips Dragon’s Wings After Investigation”