Moisture Duck Gives You A Green Thumb

May 9, 2023 by Al Williams 19 Comments

Around the Hackaday bunker, any plant other than a cactus has a real chance of expiring due to thirst. Perhaps we should build some of [MakersFunDuck]’s Moisture Duck boards. As you can see in the video below, the simple PCB with an ATtiny13A tells you when it is time to water the plants. The video also covers several exotic methods of determining the watering status, some of which are pretty complex.

The board is simple because the operation of the device is simple. A fixed resistor creates a voltage divider with the soil, and dry soil has higher resistance than moist soil. A pot sets a threshold, and the microcontroller measures the voltages.

Of course, if you can’t remember to water the plants, you probably can’t remember to change batteries either. So the device sleeps most of the time, and only wakes up every eight seconds to conserve battery. It would be nice to alarm on a low battery, and, honestly, we would probably have made the sleep time longer.

The video covers how he minimizes corrosion, but we aren’t sure how well the board will survive in damp soil, but with a little protection, it might last a while. Besides that, you could probably just consider them almost disposable.

If you are really lazy, you can also automate the actual watering. You can even build that into a smart flower pot.

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My Great-Great-Grandad, The Engineer Who Invented A Coffee Pot

May 1, 2023 by Jenny List 32 Comments

In the study of genealogy it’s common to find people who will go to great lengths involving tenuous cross-links to establish royalty or famous figures such as George Washington or William Shakespeare in their family tree. There’s no royal blood and little in the way of fame to be found in my family tree, but I do have someone I find extremely interesting. One of my great-great-grandfathers was a Scottish engineer called James R Napier, and though his Wikipedia entry hasn’t caught up with this contribution to 1840s technology, he was the inventor of the vacuum coffee pot.

He was born in Glasgow in 1821 and was the son of a successful shipbuilder, Robert Napier, into whose business he followed once he’d received his education. He’s probably most well known today for his work in nautical engineering and for inventing Napier’s Diagram, a method for computing magnetic deviance on compass readings, but he was also a prolific engineer and author whose name crops up in fields as diverse as air engines, weights and measures, drying timber, and even the analysis of some dodgy wine. The coffee percolator was something of a side project for him, and for us it’s one of those pieces of family lore that’s been passed down the generations. It seems he was pretty proud of it, though he never took the trouble to patent it and and thus it was left to others to profit from that particular invention.

Vacuum Coffee Pots: Impressive, But Slooow

Just what is a vacuum coffee pot, and what makes it special? The answer lies in the temperature at which it infuses the coffee. We take for granted our fancy coffee machinery here in the 21st century, but a century and a half ago the making of coffee was a much simpler and less exact process. Making coffee by simply boiling grounds in water can burn it, imparting bitter flavours, and thus at the time a machine that could make a better cup was seen as of some importance. Continue reading “My Great-Great-Grandad, The Engineer Who Invented A Coffee Pot” →

When Your Smart Light Switches Stop Working, Build Your Own

April 30, 2023 by Lewin Day 14 Comments

If you want smart light switches in your house, you can buy from any one of hundreds of manufacturers. [Brian Boyle] had kitted out his home with TP Link devices, but after a few years of use, he found they all suddenly failed within a few months of each other. Decrying the state of things, he set about building his own instead.

[Brian]’s switches use the ESP32 for its handy in-built WiFi hardware. His aim was to produce smart switches that would fit neatly into standard “Decor” style switch boxes. The design uses two PCBs. One is charged with handling the mains power side of things. It carries an SPDT relay for switching AC power, and a DC power supply to run the ESP32 itself. The controller board holds the microcontroller, a Neopixel as a status indicator, and a pair of buttons — one for switching the lights on and off, the other for resetting to default settings. The physical housing is 3D printed, and looks great with the glowing status indicator in the middle of the switch.

[Brian]’s switches are triggerable via MQTT, a web interface, and the physical button onboard the device itself. Having built the devices on his own, he’ll be well-placed to troubleshoot any usability or reliability issues that crop up in the future. That’s a lot more than we can say about most smart devices on the market!

Printed Gas Can Accessories Make Refueling A Little Neater

April 26, 2023 by Dan Maloney 44 Comments

No matter what your position is on internal combustion engines, it’s pretty safe to assume everyone is on the same page regarding wasting fossil fuels: it’s a bad thing. And nothing is as frustrating as spilling even a drop of the precious stuff before you even get a chance to burn it.

Unfortunately, the design of gas cans, at least here in North America, seems to have been optimized for fuel spillage. Not willing to settle for that, [avishekcode] came up with a 3D-printable replacement nozzle that should make dispensing gas a bit neater. It’s designed to fit one of the more popular brands of gasoline jugs available here in the States, and rather than the complicated stock nozzle, which includes a spring-operated interlock that has to be physically forced into a filler neck to open the valve, the replacement is just a slender tube with a built-in air vent. The vent keeps a vacuum from forming in the gas can and makes for a smooth, easy-to-control flow of gas and less spillage. The video below shows it in action.

The obvious issue here is chemical compatibility, since gasoline doesn’t work and play well with all plastics. [avishekcode] reports that both PLA and PETG versions of the nozzle have performed well for up to two years before cracking enough to need replacement. And then, of course, the solution is just to print another one. There may be legal issues, too — some localities have ordinances regarding gasoline storage and dispensing, so it’s best to check before you print.

Of course, one way to avoid the problems associated with storing and dispensing gasoline is to convert to electric power tools and vehicles. But as we’ve seen, that presents other problems.

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Hacking An Apartment Garage Door With New Remotes

April 19, 2023 by Lewin Day 28 Comments

[Old Alaska] had a problem. He needed a second remote for his apartment garage door, but was quoted a fee in the hundreds of dollars for the trouble of sourcing and programming another unit. Realizing this was a rip-off given the cheap hardware involved, he decided to whip up his own sneaky solution instead.

It’s a simple hack, cheap and functional. An RF-activated relay with two remotes was sourced online for the princely sum of $8. [Old Alaska] then headed down to the equipment cabinet in the garage, opening the lock with the side of his own car key. He then wired the relay in parallel with the existing manual pushbutton for activating the garage door.

Sometimes, a hack doesn’t have to be complicated to be useful. Many of us might have jumped straight to trying to capture and emulate the existing remote’s radio signals. There was really no need. With physical access, [Old Alaska] was able to simply wire in his own remote entry setup himself.

We’ve seen similar hacks before, albeit achieved with SIGINT methods instead. Video after the break.

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Send This FPV Bot Into The Crawlspace To Do Your Dirty Work

April 18, 2023 by Dan Maloney 27 Comments

The least pleasant space in most houses is likely to be the space below it. Basements tend to be dank, dusty, and full of too many things that have too many legs. And even worse than the full basement is the dreaded crawlspace, which adds claustrophobia to the long list of unpleasantries that lie below. Sadly, though, a crawlspace might be a handy place to run wires, and if you’re hesitant to delve too deeply, this FPV cable-laying rig might be something to keep in mind.

This one comes to us from [Old Alaska] with very little detail other than what’s in the brief video below. The setup is clear enough — a need to run an Ethernet cable from one side of the house to the other, and a crawlspace to do it in. Also in the toolkit was an RC rock crawler with a field-expedient FPV camera. With Breaking Bad-style access to the crawlspace through a few floorboards, [Old Alaska] was able to deploy the crawler dragging a Cat 5 cable behind it. The terrain under the house made the rock crawler a good choice, with four-wheel-drive, locking differentials, and an articulating frame. The bot’s-eye view also makes it clear that actually crawling in this rubble-strewn crawlspace would be a painful affair.

With very little drama, [Old Alaska] was able to navigate the crawler across the crawlspace to the outer wall of the house, where he could fish the wire out and complete the connection — no fuss, no muss, no bloody knees. The only quibble we’d have is not running an extra length of pull rope with the wire. You never know when it’ll come in handy.

The whole thing reminds us of a more tactical version of [Cliff Stoll]’s subterranean inventory management bot.

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A wall mounted picture frame with an e-ink newspaper displayed.

A Wall Mounted Newspaper That’s Extra

April 17, 2023 by Abe Connelly 7 Comments

E-Ink displays are becoming more ubiquitous and with their low power draw, high contrast and hackability, we see many projects use them in framed wall art, informational readouts and newspaper displays. [Sho] uses this idea to create a wall mounted newspaper packed full of features.

[Sho] describes using a 13.3 inch ED133UT2 1600×1200 E-Ink display with an ITE IT8951 electronic paper display (EPD) driver, controlled by an ESP32. An RV-3028-C7 real time clock (RTC) is used to keep time and to wake up the ESP32 and other devices for daily refreshes. A 3.7V 1100mAh LiPo battery provides power through an MT3608 boost converter module to provide the 5V needed, with the E-Ink display driver further isolated from the power behind a KY-019 5V relay module to avoid unnecessary power draw when not needed.

The backend software uses the OpenWeatherMap API to get daily weather reports and scrapes news websites which are then fed through an OpenAI ChatGPT API to provide summaries. [Sho] reports that text is formatted using a combination of LuaTeX, Ghostscript, ImageMagick and other scripts to format the eventual displayed graphics, including newspaper texture and randomely placed coffee stain effects.

Be sure to check out [Sho]’s project page for some more details. E-Ink displays are still a bit pricey but the effect is hard to beat and they make great options for projects like infinite generative landscapes or low power weather stations.