Bed Sensors Do More Than You’d Think

December 21, 2023 by Kristina Panos 24 Comments

Bed sensors do sort of sound like a gimmick — after all, who cares whether someone is occupying the bed? But if you think about it, that information is quite useful from a home automation standpoint. A person could do all sorts of things in this state, from ensuring the overhead lights in the room can’t come on, to turning off other smart devices that are likely not being used while both occupants are sleeping.

[The Home Automation Guy] presents a couple of ways of doing this, but both center around a fairly inexpensive pressure-sensing mat.

In the first method, he connects the pressure mat up to a Zigbee Aqara Leak Sensor, which conveniently has two terminals on the back to accept the wires from the pressure sensor. Then he simply connects it up to a Zigbee-compatible home assistant like the Aqara Hub.

In slightly harder mode, he forgoes the Aqara Leak Sensor and connects the pressure mat up to an ESP32 using a nifty screw terminal dev board. Then he sets up the sensor and all the desired actions in ESPHome. Of course, with an ESP32, it’s easy to add a second pressure mat for [Mrs. The Home Automation Guy]’s side of the bed.

Now, once they’ve both gone off to bed, the house goes into night mode — all the smart plugs, Sonos devices, and other things are powered down, and the alarm system is put into night mode. Be sure to check out the build video after the break.

Continue reading “Bed Sensors Do More Than You’d Think” →

No TP? No Problem!

November 16, 2023 by Jenny List 42 Comments

Among First World Problems, there can be few worse than running out of toilet paper. The horror! If you’re not able to do as we did yesterday and borrow a pack until more can be bought, then you’re not without options. A handy copy of the Daily Mail could be cut into squares and hung up in your Smallest Room, or you can even make your own with the help of this handy instructional video from [whoisandrewfahmy]. It appears from a casual search to be one of many such guides that appeared during the pandemic when the bog roll supply was seen as endangered, but it’s still interesting simply as a diversion into how something is made.

The process is surprisingly straightforward, starting with scrap paper, which is shredded and soaked before being boiled to break down to pulp. The pulp is then emulsified, and some body oil is added to remove the sandpaper-on-the-butt experience before being spread between a sheet and a piece of window screen to be ironed dry. It’s an energy-intensive process, so the Daily Mail is likely to be an easier stopgap if no friends can lend you a few rolls, but it’s left us here curious about papermaking. The butts of Hackaday may be safe from homemade TP, but that’s not to say that it wouldn’t be interesting to make other paper products. Check out the video below.

Of course, back in April 2020 we had our own solution to the pandemic toilet paper shortage. After you make your bespoke dunny roll, how can you wind it into a nice roll? Don’t worry. We got you.

Continue reading “No TP? No Problem!” →

A Paper Printer For QR Code Menus

October 26, 2023 by Lewin Day 24 Comments

Do you miss the days of thumbing through a sticky, laminated booklet to order your food? Sick of restaurants and their frustrating electronic menus? Fear not, for [Guy Dupont] and his QR code menu printer are here to save the day.

Yes, that’s right — it’s a lunchbox-sized printer designed to spit out a paper version of a digital menu. Using a Tiny Code Reader from Useful Sensors, the device can scan a QR code at a restaurant to access its menu. A Seeed Studio XIAO ESP32 takes the link, and then passes it to a remote computer which accesses the menu online and screenshots it. The image is processed with TesseractOCR to extract food items and prices, and the data is then collated into a simple text-only format using ChatGPT. The simplified menu is finally sent to a thermal printer to be spat out on receipt paper for your casual perusal.

[Guy] was inspired to build the project after hating the experience of using QR code menus in restaurants and bars around town. It’s his latest project that solves an everyday problem, it makes a great sequel to his smart jeans that tell you when your fly is down.

Continue reading “A Paper Printer For QR Code Menus” →

Spinning Up A New Laundry Monitor

October 20, 2023 by Kristina Panos 17 Comments

For all that modern washers and dryers do, they don’t let you know when they’re finished. Or they do, but it’s only a short victory song that plays once and can be easy to miss. What most of us need is a gentle reminder that there’s damp laundry festering in the washer, or fresh laundry in the dryer getting wrinkly.

This laundry monitor from [Sparks and Code] is version 2.0. The first version was working fine, but it was based on vibration (or lack thereof). Fast forward a few years, and [Sparks and Code] got a modern pair that’s so finely tuned, it doesn’t produce enough vibration to register. Back to the drawing board [Sparks and Code] went, and eventually came up with version 2.0.

Now, [Sparks and Code] is detecting whether the machines are on using a pair of split-core transformers to monitor power at the breaker box. With these, you just run the wire through the hole, and it gives the relative mV value going through the wire on a 3.5mm cable. Those cables are connected to an ESP32 inside the 3D-printed box, which is mounted above the cabinet door. Since [Sparks and Code] already has home assistants all over the house, it was easy to integrate and have them all play the message ‘please flip the laundry’.

Once this project was all buttoned up, they thought of one issue — the self-cleaning cycle. Since it takes about four hours, they like to run it overnight. You can see the problem here — no one wants to hear Alexa at 3AM. Fortunately, [Sparks and Code] was able to adjust the Python script to ignore these events. Be sure to check out the build video after the break.

If only the dryer could empty itself and fold the clothes. Oh wait, there’s a robot for that.

Continue reading “Spinning Up A New Laundry Monitor” →

The Loveliest Electronics Desk You’ll See Today

September 21, 2023 by Kristina Panos 10 Comments

Does your electronics desk have a lap drawer? And is it filled with random, disorganized detritus? Well, [Handy Bear] is here to show you that you can put so much more in every drawer you’ve got if you do it right. And boy, it sure looks like [Handy Bear] did it right.

Hidden inside this beautiful antique desk is plastic storage compartment after plastic storage compartment, all situated inside custom dividers made painstakingly from 3mm MDF. The first iteration, a cubbyhole arrangement, was not modular and looked crappy by [Handy Bear]’s standards.

Back to the drawing board and the scroll saw. [Handy Bear] came up with a new scheme that mimics the dividers in the plastic storage boxes they’re using for components and more. In addition to the slotted parts are open-top boxes for things like the multimeter, helping hands, and the ever-important label maker.

[Handy Bear] used hot glue and simple joinery for everything, sealing all the seams with a mixture of glue and water to keep it from turning to dust. We especially like the caliper holder for the lap drawer. You’ll notice that not quite everything fits inside the desk, so [Handy Bear] put the bigger stuff on a couple of IKEA carts. Be sure to check out the short build video and take the desk tour after the break.

Don’t have room for a whole desk worth of stuff? Build an electronics lab in a box!

Continue reading “The Loveliest Electronics Desk You’ll See Today” →

An aluminum box sits on a workbench. It is open and has a message saying "I Love You!" inserted in a wooden slot. There is a switch with a yellow LED on the front and a small compartment to the left of the wooden slot to store paper.

Share Your Feelings Like A Spy

September 8, 2023 by Navarre Bartz 13 Comments

While hackers can deftly navigate their way through circuit diagrams or technical documentation, for many of us, simple social interactions can be challenge. [Simone Giertz] decided to help us all out here by making a device to help us share our feelings.

Like an assignment in Mission: Impossible, this aluminum box can convey your confessions of love (or guilt) and shred them after your partner (or roommate) reads the message. The box houses a small shredder and timer relay under a piece of bamboo salvaged from a computer stand. When the lid is opened, a switch is depressed that starts a delay before the shredder destroys the message. The shredder, timer, and box seem almost made for each other. As [Giertz] says, “Few things are more satisfying than when two things that have nothing to do with each other, perfectly fit.”

While seemingly simple, the attention to detail on this build really sets it apart. The light on the front to indicate a message is present and the hinged compartment to easily clean out shredded paper really make this a next-level project. Our favorite detail might be the little space on the side to store properly-sized paper and a marker.

While the aluminum box is very industrial chic, we could see this being really cool in a vintage metal lunch box as well. If you’re looking for other ways to integrate feelings and technology, checkout how [Jorvon Moss] brings his bots to life or how a bunch of LEDs can be used to express your mood.

Continue reading “Share Your Feelings Like A Spy” →

A graphic showing the suggested footprint dimensions for 0402 parts

Want Better 0402 Reflow? Consider These Footprints!

February 1, 2023 by Arya Voronova 13 Comments

Assembling with a stencil is just that much more convenient – it’s a huge timesaver, and your components no longer need to be individually touched with a soldering iron for as many times as they have pads. Plus, it usually goes silky smooth, the process is a joy to witness, and the PCB looks fantastic afterwards! However, sometimes components won’t magically snap into place, and each mis-aligned resistor on a freshly assembled board means extra time spent reflowing the component manually, as well as potential for silent failures later on. In an effort to get the overall failure rate down, you will find yourself tweaking seemingly insignificant parameters, and [Worthington Assembly] proposes that you reconsider your 0402 and 0201 footprints.

Over the years, they noticed a difference in failure rates between resistor&capacitor footprints on various boards coming in for assembly – the size and positioning of the footprint pads turned out to be quite significant in reducing failure rate, even on a tenth of millimeter scale. Eagle CAD default footprints in particular were a problem, while a particular kind of footprint never gave them grief – and that’s the one they recommend we use. Seeing the blog post become popular, they decided to share their observations on 0201 as well, and a footprint recommendation too. Are your 0402 resistors giving you grief? Perhaps, checking the footprints you’re using is a good first step.

The 0402 and 0201 components are in a weird spot, where soldering iron assembly is no longer really viable, but the stencil+reflow approach might not be unilaterally successful when you start off – fortunately, that’s where writeups like these come in. Interested in learning stenciling? Get some solder paste, and read up on all the different ways you can put it onto your boards.