Autonomous Plant Watering Thingamajig

[Eitan] is one of those guys whose plants keep tottering between life and death. Can’t blame the plants, because he just keeps forgetting when to water them. But keeping them hydrated requires him to get off his butt and actually water them. Surely, there had to be an easier solution which needed him to do nothing and yet prevent his plants from dying. Being lazy has its benefits, so he built his own super simple Autonomous Plant Watering Thingamajig.

He needed a water pump, but all he had was an air pump. So he hooked it up to force air in to a sealed container and push the water out. To make the setup autonomous, he connected the pump to a WiFi-enabled wall socket and then programmed it to dispense water at regular intervals. It may take him some time to fine tune the right interval and duration for his setup over the next few weeks, but right now, it’s pumping water for a short duration once every week.

The important thing for a system like this to work is to ensure it is well sealed. Any air leakage will require an increasing amount of air to be pumped in to the container as the water level keeps reducing. Without knowing the actual level of water in the container, it isn’t easy to compensate for this via programming. And that’s the other problem. [Eitan] will still have to periodically check his mason jar for water, and top it up manually. Maybe his next hack will take care of that. We’re thinking a Rube Goldberg watering system would be awesome. It’s nice when people put on their thinking caps and say “Okay, here’s a problem, how do I solve it?” instead of going out and buying an off-the-shelf device.

Thanks, [Clay], for sending in this tip.

Greet The Sun With A 555 Flute

Here’s an interesting implementation of a classic: the 555 timer as astable multivibrator for the noble purpose of making weird music. [pratchel] calls this a Morgenflöte or morning flute, indicating that it is best played in the morning. It would certainly wake up everyone in the house.

Instead of using LDRs in straight-up Theremin mode and waving his hands about, [pratchel] mounted one in each of several cardboard tubes. One tube is small and has just a few holes; this is intended to be used as a flute. [pratchel] cautions against locating holes too close to the LDR, because it will overpower the others when left uncovered. A larger tube with more holes can be used as a kind of light-dependent slide whistle with another holey tube that fits inside. We were disappointed to find that the giant tube sitting by the amplifier hasn’t been made into a contrabass flute.

Continuing the theme of astability, [pratchel] went completely solderless and built the circuit on a breadboard. The LDR’s legs are kept separate by a piece of cardboard. This kind of project and construction is fairly kid and beginner-friendly. It would be a good one for getting your musically inclined friends and family members into electronics. Here’s a 555 player piano built by Hackaday’s own [Steven Dufresne] that might be a good second step. Check out [pratchel]’s performance after the break.

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Hexapod Tank From Ghost In The Shell Brought To Life

Every now and then someone gets seriously inspired, and that urge just doesn’t go away until something gets created. For [Paulius Liekis], it led to creating a roughly 1:20 scale version of the T08A2 Hexapod “Spider” Tank from the movie Ghost in the Shell. As the he puts it, “[T]his was something that I wanted to build for a long time and I just had to get it out of my system.” It uses two Raspberry Pi computers, 28 servo motors, and required over 250 hours of 3D printing for all the meticulously modeled pieces – and even more than that for polishing, filing, painting, and other finishing work on the pieces after they were printed. The paint job is spectacular, with great-looking wear and tear. It’s even better seeing it in motion — see the video embedded below.

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1575 Bottles Of Beer On The (LED) Wall

Say hello to my little friend, lovingly named Flaschen Taschen by the members of Noisebridge in San Francisco. It is a testament to their determination to drink Corona beer get more members involved in building big displays each year for the Bay Area Maker Faire. I pulled aside a couple of the builders for an interview despite their very busy booth. When you have a huge full-color display standing nine feet tall and ten feet wide it’s no surprise the booth was packed with people.

Check out the video and then join me after the break for more specifics on how they pulled this off.

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Designing Circuits With Switching Algebra

We return once again to the work of Dr. Claude E. Shannon, this time to his Masters thesis on relay switching circuit design. This thesis introduced switching algebra that allows the systematic design and optimization of logical circuits. While Shannon’s work applied to switches and relays, it is equally applicable to all the modern forms of digital circuits. His thesis received widespread notice when published as “A Symbolic Analysis of Relay and Switching Circuits” in 1938. This work built on the Boolean algebra developed by George Boole and an analysis of logic by Augustus De Morgan which these mathematicians published nearly simultaneously in 1847. To some extent, it was the beginning of the age of modern digital logic. Continue reading “Designing Circuits With Switching Algebra”

Morse Code: Paris In The Mint Box

TinyLilyThumbnail[Rob Bailey] likes to build things and he likes ham radio. We are guessing he likes mints too since he’s been known to jam things into Altoids tins. He had been thinking about building a code practice oscillator in a Altoids Smalls tin, but wasn’t sure he could squeeze an Arduino Pro Mini in there too. Then he found the TinyLily Mini. The rest is history, as they say, and 1CPO was born.

The TinyLily Mini is a circular-shaped Arduino (see right) about the size of a US dime. most of the pads are arranged around the circle and there is a small header that takes a USB programmer. A small rechargeable battery can run the device for a long time.

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Hands-On With The BBC Micro:Bit

It’s been a long wait, but our latest single board computer for review is finally here! The BBC micro:bit, given free to every seventh-grade British child, has landed at Hackaday courtesy of a friend in the world of education. It’s been a year of false starts and delays for the project, but schools started receiving shipments just before the Easter holidays, pupils should begin lessons with them any time now, and you might even be able to buy one for yourself by the time this article goes to press.

The micro:bit top view
The micro:bit top view

It’s a rather odd proposition, to give an ARM based single board computer to coder-newbie children in the hope that they might learn something about how computers work, after all if you are used to other similar boards you might expect the learning curve involved to be rather steep. But the aim has been to position it as more of a toy than the kind of development board we might be used to, so it bears some investigation to see how much of a success that has been.

Opening the package, the micro:bit kit is rather minimalist. The board itself, a short USB lead, a battery box and a pair of AAA cells, an instruction leaflet, and the board itself.  Everything is child-sized, the micro:bit is a curved-corner PCB about 50mm by 40mm. The top of the board has a 5 by 5 square LED matrix and a pair of tactile switches, while the bottom has the surface-mount processor and other components, the micro-USB and power connectors, and a reset button. Along the bottom edge of the board is a multi-way card-edge connector for the I/O lines with an ENIG finish. On the card edge connector several contacts are brought out to wide pads for crocodile clips with through-plated holes to take 4mm banana plugs, these are the ground and 3V power lines, and 3 of the I/O lines.

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