Plant’m If You Got’m And Keep’m Alive

Having a few plants around is a great way to liven up your living and/or working space. They look nice, you get to watch them grow and change, and some types of plants can actively improve the room’s air quality. But let’s face it — even the easy ones require a baseline level of care that can easily fall by the wayside. After all, the poor things can’t scream out for water or get up and find a sunnier spot for themselves.

[Ine Hocedez] was tired of watching her plants die and not knowing why. The two main culprits involve water and light, though there can be other issues like soil pH and bugs. It’s easy to get the balance wrong, so why not automate everything?

Plant’m is a complete, portable package that [Ine] designed for a school project. A soil moisture sensor dictates the watering schedule via Raspberry Pi, and water is automatically pumped from an elevated tank.

The lamp is meant to supplement the sunlight, not replace it. But that’s the real beauty of this botanical box — [Ine] can just pick it up and try a different spot if the plant droops or shows burnt spots.

Got the sunlight part down for your plant, but can’t remember to water it? Re-purpose an old Keurig and give it an automatic drip.

Learn Quantum Computing With Spaced Repetition

Everyone learns differently, but cognitive research shows that you tend to remember things better if you use spaced repetition. That is, you learn something, then after a period, you are tested. If you still remember, you get tested again later with a longer interval between tests. If you get it wrong, you get tested earlier. That’s the idea behind [Andy Matuschak ‘s]and [Michael Nielsen’s] quantum computing tutorial. You answer questions embedded in the text. You answer to yourself, so there’s no scoring. However, once you click to reveal the answer, you report if you got the answer correct or not, and the system schedules you for retest based on your report.

Does it work? We don’t know, but we have heard that spaced repetition is good for learning languages, among other things. We suspect that like most learning methods, it works better for some people than others.

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Scanning Analog Film For The Last Time

Film cameras are capable of great resolution, and for a long time were superior in this regard to their digital successors. However, it’s now possible to store digital copies of analog images in superior detail, so [Jan] built a rig to scan their photos for the last time.

The general idea is to take a high enough resolution scan of film negatives or slides, such that there is no need to rescan the images when technology moves forward. To achieve this, [Jan] decided to employ a DSLR to photograph the materials in question. To do this quickly and accurately, with minimal fuss, special lens hoods were 3D printed to hold slides in perfect register in front of the lens. With a flash to provide even light, the results are excellent. Film negatives proved harder, requiring a carefully designed transport mechanism to avoid damaging the fragile materials. With some perseverance, the final tool worked well.

It’s a tidy way of digitally archiving analog photos, and with the resolution of modern cameras, one needn’t worry about lost resolution. We’ve seen mechanised builds for handling other formats too, such as this 8mm scanner. Video after the break.

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Vintage Keyboard Gets The QMK Treatment

While nobody could deny that computing technology has some a long way in the last few decades, there are many out there who believe peak keyboard was sometime before the turn of the new millennium. They prefer the look, feel, and especially the sounds, of those classic keyboards to what passes for an input device these days. So much so that it’s not uncommon to see one of these old mammoths get freshened up and pushed into service with a modern computer.

Which is exactly what [Juan Pablo Kutianski] has done with his Compaq MX-11800. This keyboard, which is actually a branded version of the Cherry G80-11800, really stands out in a crowd. With an integrated trackball and a two-row arrangement for the function keys, it’s not hard to see why he’d want to show it off. But while the hardware itself was solid, the features and capabilities of this old school keyboard left something to be desired.

The solution was to replace the keyboard’s original electronics with a Teensy++2.0 running the popular QMK firmware. This not only made the keyboard USB, but allowed [Juan] to tweak things such as the trackball sensitivity and add in support for layers and macros. All of which can be managed through VIA, a graphical configuration tool for QMK.

As we’ve seen in so many projects, the combination of QMK running on the Teensy is a powerful tool for getting the most out of your keyboard. Whether breathing new life into a vintage piece of hardware or creating something truly custom like our very own [Kristina Panos] recently did, it’s definitely something to keep in mind if you’re considering any keyboard hacking.

Message In A Bottle: Bicycle Trailer On A Mission

Graffiti is a controversial subject, and whether you see it as art or vandalism usually depends where and how you come across it. From the scribbled tag on a house wall, to highly sophisticated murals, they tend to have one thing in common though: making a statement — whether that’s political, showing appreciation, or a simple “I was here”. [Sagarrabanana] had his own statement to make, but chose a less permanent way to express himself with his type of graffiti.

Unhappy about the lack of dedicated cycle lanes in his area, he built an automatic, Arduino-controlled water dispensing bicycle trailer, writing his message on every street he rides on. The build is documented in a video, and shown in action in another one — which are both in Spanish (and also embedded after the break), but pictures are worth their thousand words in any language.

Inspired by persistence of vision (POV), where moving LEDs sync up their blinking to give the illusion of a static image, [Sagarrabanana] transformed the concept to water on a road using an array of solenoids attached to a water tank. Each solenoid is controlled by a relay, and a predefined font determines when to switch each relay — the same way pixels on a display would be set on or off, except small amounts of water are squirted out as the bicycle is moving along. The message itself is received via serial Bluetooth module, and can be easily modified for example from a phone. To adjust the water dispensing to the cycling speed, the whole system is synced to a magnetic switch mounted to one of the trailer’s wheels, so you could theoretically take it also with you on a run.

Time will tell if [Sagarrabanana]’s mission has the success he hopes for, but there’s no doubt the trailer will attract attention anywhere he goes. Well, we wish him all the best to get the message through without requiring a too drastic alternative as writing medium. Although, we’ve seen a graffiti robot that uses chalk spray in the past, so there’s certainly room for a not-too-permanent upgrade if needed.

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Loading Coils, The Heaviside Condition, And Pupin Coils

When we draw schematics, we have the luxury of pretending that wire is free. There are only a few cases where you have to account for the electrical characteristics of wire: when the wire is very long or the frequency on the wire is relatively high.

This became apparent after the first transatlantic cable went into service for telegraph communications. Even though the wire was linear, there was still distortion on the line so severe that dots and dashes would overlap each other. The temporary solution was to limit speeds so slow that operators had trouble sending and receiving at those speeds. How slow? An average character took two minutes to send! That’s not a typo. Two minutes per character. By custom, Morse code assumes a word is five characters, so you could send a word every 10 minutes.

The first transatlantic cable went into service in 1858 and was virtually the moon landing of its day. Frustrated with how slow the communications were, an electrician by the name of Whitehouse decided to crank up the voltage to over 1,000 volts which caused the cable to fail after only three weeks in service. Whoops. Later analysis showed the cable was probably going to fail quickly anyway, but Whitehouse took the public blame.

The wire back then wasn’t as good as what we have today, which led to some of the problems. The insulation was made from multiple coats of a natural latex, gutta percha, which is what dentists use to fill root canals. The jackets were made from tarred hemp and bound with iron wire. There was no way to build an underwater amplifier in 1858, so the cables were just tremendous wires laying on the ocean floor between Newfoundland and Ireland.

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Hackaday Podcast 072: Robo Golf Clubs, Plastic Speedboats, No-Juice Flipdots, And Super Soakers

With Editor-in-Chief Mike Szczys on a well-earned vacation, Staff Writer Dan Maloney sits in with Managing Editor Elliot Williams to run us through the week’s most amazing hacks and answer your burning questions. What do you do when you can’t hit a golf ball to save your life? Build a better club, of course, preferably one that does the thinking for you. Why would you overclock a graphing calculator? Why wouldn’t you! Will an origami boat actually float? If you use the right material, it just might. And what’s the fastest way to the hearts of millions of kids? With a Super Soaker and a side-trip through NASA.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (~65 MB)

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