Cat-o-Matic 3000 Serves Your Feline Masters

December 1, 2023 by Kristina Panos 8 Comments

When you have three cats and three humans, you have one problem: feeding them on a schedule without over or under feeding them. Even if there was only one human in the equation, the Cat-o-Matic 3000 would still be a useful tool.

Essentially, it’s a traffic light for cats — where green means you are go for feeding, and red means the cat was just fed. Yellow, of course, means the cat is either half-full or half-empty, depending on your outlook.

The brains of this operation is an ATmega88PA leftover from another project. There’s a no-name voltage regulator that steps up the two AA cells to 5 volts. Timing comes from a 32 kHz crystal that allows the microcontroller to stay in power-saving sleep mode for long periods of time.

Creator [0xCAFEAFFE] says the firmware was cobbled together from other projects. Essentially, it wakes up once per second to increment the uptime counter and then goes back to sleep. Short-pressing a button shows the feeding status, and long-pressing it will reset the timer.

Wanna make a cat status indicator without electronics? Give flexures a try.

Iowa Demolishes Its First 3D Printed House

November 29, 2023 by Kristina Panos 130 Comments

It sounds like a headline from the future: the weekend before Thanksgiving, a bulldozer came for the first example of a printed home that was supposed to help the housing crisis in the city of Muscatine. Fortunately, it hadn’t been completed and sold yet.

Printing of this first house began in May 2023, and nine more were to be completed by the end of the year. Unfortunately, when tested for compressive strength, the cement mixture this first home was printed out of failed to meet the 5,000 PSI minimum required for the project. Rather than compromise on safety, the parties involved decided to knock it down and start over.

The goal now is to find out why the mixture, which met the strength requirements in laboratory testing, didn’t behave the same on-site. Currently, the plan is to start building the originally-planned second house in the spring, and begin construction on this first site after that.

The project is a collaborative effort between the Community Federation of Greater Muscatine (CFGM), Muscatine Community College, and Alquist 3D. Want to know more about the state of 3D printing when it comes to housing? Check out our handy guide.

Editors Note: The initial post initially indicated that the failed cement mixture contained hemp, but that has since found to be incorrect and the post has been edited accordingly.

Continue reading “Iowa Demolishes Its First 3D Printed House” →

Heat Pump Dryer Explained

November 25, 2023 by Al Williams 98 Comments

Historically, having a washer and a dryer in your house requires “a hookup.” You need hot and cold water for the washer as well as a drain for wastewater. For the dryer, you need either gas or — in the US — a special 220 V outlet because the heating elements require a lot of wattage, and doubling the voltage keeps the current levels manageable. You also need a bulky hose to vent hot moist air out of the house. But a relatively new technology is changing that. Instead of using a heater, these new dryers use a heat pump, and [Matt Ferrell] shows us his dryer and discusses the pros and cons in a video you can below. We liked it because it did get into a bit of detail about the principle of operation.

These dryers are attractive because they use less power and don’t require gas or a 220 V outlet. They also don’t need a vent hose which means they can sit much closer to the wall and take up less space. Heat pumps don’t convert electrical energy into heat like a normal heating element. Instead, it uses a compressor to move heat from one place to another. In this case, the dryer heats the air using the heat pump. That causes water in the clothes to evaporate into the air. The heat pump dryer then uses a second loop to cool the air, condensing the water out so the it can reheat the air and start the whole cycle over again.

Continue reading “Heat Pump Dryer Explained” →

DIY Smart Washing Machine Redesign

November 24, 2023 by Al Williams 17 Comments

[Mellow Labs] wanted a smart washer and built a simple controller. However, he found out after a few weeks it wasn’t working how he wanted. The detergent quit flowing, and he washed clothes with no soap for a week! So, a redesign was in order. You can follow the process and the result in the video below.

A bit of 3D printing, a larger pump, and proper voltage made a big difference. We didn’t see the print files, but unless you have the exact same setup, you’d probably have to customize it anyway. There is a real-time hand-drawn schematic, and the software is probably not hard to pull off the video screen (it is only 18 lines).

Continue reading “DIY Smart Washing Machine Redesign” →

A brown, wooden picture frame with a white matte holds a slightly pixelated photo of gaming miniatures. It is sitting on a wooden table.

A Colorful Take On The E-Ink Photo Frame

November 21, 2023 by Navarre Bartz 7 Comments

Everyone loves sharing photos, and with most pictures being taken on smartphones now, digital frames are more convenient than finding a photo printer. [Wolfgang Ziegler] used an e-ink screen to create a colorful digital picture frame.

Starting with a seven color e-ink HAT he’d forgotten he had, a spare Pi Zero, and analog photo frame, he pieced the parts together into a pretty slick, sunlight readable photo frame. [Ziegler] details how he set up the frame to display new images using the Pimoroni inky library. He set a fifteen minute refresh interval since the color e-ink display takes 30 seconds to refresh to keep it from looking weird too often.

With the holidays coming up, this might make a perfect gift for family that wants to see the latest from your travels without blasting it to the whole internet. We’ve covered a few different options from a lightweight ESP8266 build, to this one that can rotate, and even issues with some of the commercial options.

Does Getting Into Your Garage Really Need To Be Difficult?

November 9, 2023 by Dan Maloney 78 Comments

Probably the last thing anyone wants when coming home from a long day at work or a trip is to be hassled at the last possible moment — gaining entrance to your house. But for some home automation enthusiasts, that’s just what happened when they suddenly learned that their own garage doors had betrayed them.

The story basically boils down to this: Chamberlain, a US company that commands 60% of the garage door market, recently decided to prevent “unauthorized usage” of their MyQ ecosystem through third-party apps. Once Chamberlain rolled out the change, users of Home Assistant and other unauthorized apps found themselves unable to open or close their doors with the apps they were accustomed to.

Those of us with custom smart home setups can relate to how frustrating it is when something disturbs the systems you’ve spent a lot of time tweaking and optimizing. It’s especially upsetting for users who both Chamberlain hardware specifically because it was supported by Home Assistant, only to have the company decide to drop support. This feels like false advertising, but we strongly suspect that buried in the EULA users must have agreed to at some point is a clause that essentially says, “We can do anything we want and tough noogies to you.” And if you read through the article linked above, you’ll get an idea why Chamberlain did this — they probably didn’t like the idea that users were avoiding their ad-spangled MyQ app for third-party interfaces, depriving them of ad revenue and the opportunity for up-selling.

We feel the frustration of these users, but rather than curse the darkness, perhaps this will light a candle of righteous rage that leads to a clever workaround. The Home Assistant blog article mentions a dongle called ratgdo, which should allow any door with plain old dry contacts to work via MQTT or ESPHome. It’s extra work that users shouldn’t have to put in, but maybe getting one over on The Man would be worth the effort.

Thanks to [KC] for the tip; please keep us posted on your workaround.

3D Printing Improves Passive Pixel Water Gauge

November 8, 2023 by Dan Maloney 9 Comments

Here at Hackaday, we feature all kinds of projects, and we love them all the same. But some projects are a little easier to love than others, especially those that get the job done in as simple a way as possible, with nothing extra to get in the way. This completely electronics-free water gauge is a great example of doing exactly as much as needs to get done, and not a bit more.

If this project looks a bit familiar, it’s because we featured [Johan]’s previous version of “Pixel Pole” a few years back. Then as now, the goal of the build is to provide a highly visible level gauge for a large water tank that’s part of an irrigation system. The basic idea was to provide a way of switching a pump on when the tank needed filling, and off when full. [Johan] accomplished this with a magnetic float inside the tank and reed switches at the proper levels outside the tank, and then placed a series of magnetic flip dots along the path of the float to provide a visual gauge of the water level. The whole thing was pretty clever and worked well enough.

But the old metal flip dots were getting corroded, so improvements were in order. The new flip dots are 3D printed, high-visibility green on one side and black on the other. The only metal parts are the neodymium magnet pressed into a slot in the disc and a sewing pin for the axle. The housing for each flip dot is also printed, with each module snapping to the next so you can create displays of arbitrary height. The video below shows printing, assembly, and the display in action.

[Johan]’s improvements are pretty significant, especially in assembly; spot-welding was a pretty cool method to use in the first version, but printing and snapping parts together scales a lot better. And this version seems like it’ll be much happier out in the elements too. Continue reading “3D Printing Improves Passive Pixel Water Gauge” →