A dark grey couch with a white pegboard on a drawer slide protruding from its arm. The pegboard has a magazine holder, pen holder, and several other miscellaneous bins holding odds and ends on it.

Sofa Armrest Is A Nifty Storage Spot

February 26, 2023 by Navarre Bartz 7 Comments

If you’re like us, you’re always in need of a little more space to store things. [Javier Guerrero] realized his sofa wasn’t living up to its full storage potential and designed this sofa armrest storage.

[Guerrero]’s sofa arms were hiding 80 liters of space, so he really wanted to do something with it. After disassembling them, he found his original plan of just cutting them up wouldn’t work due to the minimal structure inside. Not to be discouraged, he drew up some plans and built replicas from 15 mm plywood.

For one armrest, he made a single giant box that opens from the top where he can store a couple of folding chairs. On the other side, he made a shorter top-opening bin for charging phones and storing the remote. Underneath that is a large pull out drawer with a pegboard for organizational bliss.

The arms were upholstered using the fabric from the original arms plus a little extra from another slip cover. Separate arm modules and easily obtainable matching fabric aren’t a given for every couch, but we expect that almost any sofa with arms could benefit from this hack given a little ingenuity.

If you’re looking for more storage hacks, checkout this Modular Storage from Old Filament Spools, the Last Component Storage System You’d Ever Need, or the ever popular Gridfinity.

Pi Pico Calculates Water Usage

February 25, 2023 by Bryan Cockfield 18 Comments

Modern WiFi-enabled microcontrollers have made it affordable and easy to monitor everything from local weather information to electricity usage with typically no more than a few dollars worth of hardware and a little bit of programming knowledge. Monitoring one’s own utility data can be a little bit more difficult without interfering with the metering equipment, but we have seen some clever ways of doing this over the years. The latest is this water meter monitoring device based on a Raspberry Pi Pico.

The clever thing here isn’t so much that it’s based on the tiniest of Raspberry Pis, but how it keeps track of the somewhat obscured water flow information coming from the meter. Using a magnetometer placed close to the meter, the device can sense the magnetic field created as water flows through the meter’s internal sensors. The magnetic field changes in a non-obvious way as water flows through it, so the program has to watch for specific peaks in the magnetic field. Each of these specific waveforms the magnetometer detects counts to 0.0657 liters of water, which is accurate for most purposes.

For interfacing with a utility meter, this is one of the more efficient and elegant hacks we’ve seen in a while. There have, of course, been other attempts to literally read the meter using web cams and computer vision software, but the configuration for these builds is much more complex than something like this. You can interface with plenty of utility meters other than water meters, too, regardless of age.

Automating The Most Analog Of HVAC Equipment

February 20, 2023 by Bryan Cockfield 35 Comments

Burning wood, while not a perfect heating solution, has a number of advantages over more modern heating appliances. It’s a renewable resource, doesn’t add carbon to the atmosphere over geologic time scales like fossil fuels do, can be harvested locally using simple tools, and it doesn’t require any modern infrastructure to support it. That being said, wood stoves aren’t something that are very high-tech and don’t lend themselves particularly well to automation as a result, at least with the exception of this wood stove from [jotulf45v2].

While this doesn’t automate the loading or direct control of a modern pellet stove, it does help [jotulf45v2] know when the best times are for loading more wood into the stove and helps keep the stove in the right temperature range to avoid the dangerous formation of creosote on the inside of his chimney caused by low temperature burns. Two temperature sensors, one on the stovetop and the other on the stove pipe, monitor the stove exhaust temperature. They feed data to a Node-RED system running on a Raspberry Pi which automatically notifies the user by text message when certain stove temperatures are reached.

For anyone heating with wood, tools like this are indispensable to help avoid spending an otherwise unnecessary amount of time getting a fire up to temperature quickly without over-firing the stove. Modern pellet stoves have some more modern conveniences like this built in, but many of the perks of using cord wood are lost with these devices. There are plenty of other ways to heat with wood too; take a look at this custom wood boiler which serves as a hot water heater.

Low Power Challenge: Weather Station Runs For Months Thanks To E-Ink Display

February 20, 2023 by Robin Kearey 1 Comment

Having a device in your living room that shows weather information is convenient, and building one of those is a great project if you enjoy tinkering with microcontrollers and environmental sensors. It’s also a great way to learn about low-power design, as [x-labz] demonstrated with their e-ink weather station which works for no less than 60 days on a single battery charge. It has a clear display that shows the local temperature and humidity, as well as the weather forecast for the day.

The display is a 4.2″ e-paper module with a resolution of 400 x 300 pixels. It uses just 26 mW of power for a few seconds while it updates its image, and basically zero watts when showing a static picture. It’s driven by a tiny ESP32C3 processor board, which downloads the weather forecast from weatherapi.com every two hours. The indoor climate is measured by an SHT-21 temperature and humidity sensor mounted behind the display, while the outdoor data is gathered by a WiFi-connected sensor installed on [x-labz]’s balcony.

The key to achieving low power usage here is to keep the ESP32 in sleep mode as much as possible. The CPU briefly wakes up once every five minutes to read out the indoor sensor and once every fifteen minutes to gather data from outside, using the relatively power-hungry WiFi module.

To further reduce power consumption, the CPU core is driven at the lowest possible clock speed at all times: 10 MHz when reading the indoor sensor, and 80 MHz when using the WiFi connection. All of this helps ensure that just one 600 mAh lithium battery can keep everything running for those 60 days.

E-ink displays are perfect for text and simple graphics that don’t change too often, which is why they’re very popular in weather stations. With a bit of tweaking though, LCDs can also be optimized for low power.

A black chandelier that looks somewhat like a fern frond. It has four lights arranged roughly in a circle around the curly end and two clustered near the tail. It is mounted on a dark wood panel ceiling.

Put A Constellation In Your Dining Room

February 18, 2023 by Navarre Bartz 3 Comments

We love lamps here at Hackaday, especially if they imitate natural light sources. [Scott McIndoe] used his love of lamps to fashion a chandelier replicating his favorite constellation, the Southern Cross.

Starting with the Southern Cross’s four major stars and the pointers of Alpha and Beta Centauri, [McIndoe] sketched out a breaking wave form between the six stars to form the spine of this light source. By using smart bulbs for each of the six star positions, he was able to set a scene that replicates the color and relative brightness of each star for that extra astronomical touch.

The top and bottom of the chandelier is laser cut from 3 mm plywood and fitted together using glue and finger joints while the sides are a wood veneer. The entire piece was sanded and coated with a bit of filler before painting. Mounting is accomplished using three eye hooks mounted on the top side of the chandelier.

If you want more celestial lamps, check out [McIndoe]’s previously-featured analemma chandelier or this lithophane moon lamp.

A Call For Better Shower Temperature Controls

February 18, 2023 by Lewin Day 144 Comments

A good shower is a beautiful, rejuvenating experience. Contrarily, a shower that’s either too hot or too cold becomes a harrowing trial of endurance. [Ben Holmen] has been musing on the way we control temperature in our showers, and he has come to the conclusion that it’s not good enough. He’s done the math, quantified the problem, and is calling for better solutions for all.

[Ben]’s plot of shower temperature vs. mixer tap angle.

[Ben]’s complaint rests with the mixer taps that have become the norm in modern shower installations. These taps have a 180-degree range of motion. On one end, you get maximum cold water output, on the other, maximum hot water output. This is fine for a kitchen sink where we often want one extreme or the other, and exact temperature isn’t important. However, for a shower, it’s terrible.

By [Ben]’s measurements, just a 10-degree range on his own shower tap corresponds to comfortable, usable temperatures. That’s means just 5.6% of the control range is devoted to temperatures the user is likely to select. His argument goes that this is the opposite of how it should work, and that most of the tap’s range should be dedicated to comfortable temperatures.

Ideal water temperature curve, compared to standard tap.

This would allow much finer control of shower temperature in the actual useful range. It would allow us to make tweaks to our shower temperature without having to ever-so-delicately nudge the mixer tap. Extreme hot and extreme cold temperatures should still be available, but left at the utter extremes.

Sadly, [Ben] doesn’t work for Big Tap, so he can’t directly influence the product sold to the public. Instead, he’s calling for manufacturers to develop shower valves that prioritize the temperatures that humans desire most. Unfortunately, it’s not immediately clear how the mechanics of such a valve would work without adding considerable cost and complexity when compared to the traditional model.

What do you think? Are things fine the way they are, or does [Ben] have a point? Perhaps you’re a two-tap evangelist! In any case, we’d love to hear your comments below. Meanwhile, if you’re more worried about the water bill than the temperature, we can help you there as well!

Machine Learning Baby Monitor, Part 2: Learning Sleep Patterns

February 16, 2023 by Dan Maloney 12 Comments

The first lesson a new parent learns is that the second you think you’ve finally figured out your kid’s patterns — sleeping, eating, pooping, crying endlessly in the middle of the night for no apparent reason, whatever — the kid will change it. It’s the Uncertainty Principle of kids — the mere act of observing the pattern changes it, and you’re back at square one.

As immutable as this rule seems, [Caleb Olson] is convinced he can work around it with this over-engineered sleep pattern tracker. You may recall [Caleb]’s earlier attempts to automate certain aspects of parenthood, like this machine learning system to predict when baby is hungry; and yes, he’s also strangely obsessed with automating his dog’s bathroom habits. All that preliminary work put [Caleb] in a good position to analyze his son’s sleep patterns, which he did with the feed from their baby monitor camera and Google’s MediaPipe library.

This lets him look for how much the baby’s eyes are open, calculate with a wakefulness probability, and record the time he wakes up. This worked great right up until ~~the wave function collapsed~~ the baby suddenly started sleeping on his side, requiring the addition of a general motion detection function to compensate for the missing eyeball data. Check out the video below for more details, although the less said about the screaming, demon-possessed owl, the better.

The data [Caleb] has collected has helped him and his wife understand the little fellow’s sleep needs and fine-tune his cycles. There’s a web app, of course, and a really nice graphical representation of total time asleep and awake. No word on naps not taken in view of the camera, though — naps in the car are an absolute godsend for many parents. We suppose that could be curated manually, but wouldn’t doubt it if [Caleb] had a plan to cover that too.

Continue reading “Machine Learning Baby Monitor, Part 2: Learning Sleep Patterns” →