The Internet Of Dirt, A Texting Plant

January 8, 2017 by 10 Comments

We will all at some point have forgotten to water a plant. If we’re lucky then the limp vegetation we return to will magically revive when we rush to water it, if not then we have the shame of an empty plant pot to remind us of our folly.

No matter, you might be thinking, we can bring technology to bear on the problem, and automate it with a microcontroller! [Bonnie] has done just that, with a capacitive soil sensor feeding an ESP8266-based Adafruit Feather HUZZAH, which in turn logs soil humidity data with the Adafruit IO online service. An IFTTT applet monitors the data, and triggers a notification when moisture falls to the point at which watering is required.

The Instructables write-up gives a comprehensive step-by-step guide to the whole process, including the code, so it’s a project that almost anyone could try as well as a basic introduction to using an online service with a piece of hardware. We can’t help asking, though, whether it might have been better to have had the system do the watering rather than merely administer a prod to its fleshy horticulturist creator. Perhaps that’s left to anyone else building one to add as an enhancement.

Quite a few plant watering automation projects have found their way onto these pages over the years, from this one using car parts to a system with an impressively simple valve made by compressing a flexible pipe. The ultimate watering device though has to be this fully autonomous greenhouse robot.

CES2017: Really Fast 3D Printing For Large Builds

January 8, 2017 by 44 Comments

About a year ago, Autodesk showed off one of the most innovative filament printers in recent memory. Project Escher is your basic Cartesian filament printer, but with a twist: it has five heads. These print heads work together to build large objects very quickly.

Autodesk open sourced the design of the Escher, and now it’s made it into commercial production thanks to Titan Robotics. The Cronus, which uses the same software as Project Escher, is big! Each of these gantries is driven by closed-loop servo motors and fancy ball screws, producing a total build volume of 77″x30″x20″. This open air version is printing in PLA. If you want to use it with materials where ambient temperature is an issue there is an option for an enclosed build environment.

This printer will be available for purchase starting February but no word yet on cost. They advertise the build volume as customizable so we expect the same of the price.

Light Dimmer Shows How To Steal Power From AC Line

January 8, 2017 by 33 Comments

We see a lot of traffic on the tips line with projects that cover old ground but do so in an instructive way, giving us insight into the basics of electronics. Sure, commercial versions of this IR-controlled light dimmer have been available for decades. But seeing how one works might just help you design your Next Big Thing.

Like many electronic controls, the previous version of this hack required a connection to a neutral in addition to the hot. This version of the circuit relies on passing a small current through the light bulb the dimmer controls to avoid that extra connection. This design limits application to resistive loads like incandescent bulbs. But it’s still a cool circuit, and [Muris] goes into great detail explaining how it works.

We think the neatest bit is the power supply that actually shorts itself out to turn on the load. A PIC controls a triac connected across the supply by monitoring power line zero-crossing. The PIC controls dimming by delaying the time the triac fires, which trims the peaks off of the AC waveform. The PIC is powered by a large capacitor while the triac is conducting, preventing it from resetting until the circuit can start stealing power again. Pretty clever stuff, and a nice PCB design to boot.

Given the pace of technological and cultural change, it might be that [Muris]’ dimmer is already largely obsolete since it won’t work with CFLs or LEDs. But we can see other applications for non-switched mode transformerless power supplies. And then again, we reported on [Muris]’s original dimmer back in 2009, so the basic design has staying power.

“Alexa, Order Everyone In San Diego A Doll House”

January 7, 2017 by 99 Comments

Every day it seems there is a new Alexa story in the news, as for the moment the Amazon voice assistant is in the ascendant over its rivals from Google, Apple, and Microsoft. Today’s slice of Alexa weirdness comes courtesy of a newsreader in San Diego, who inadvertently triggered Alexa-enabled devices within hearing distance of a television to buy doll houses when he reported on a Dallas child’s accidental purchase.

It’s unclear whether any doll houses were dispatched or whether the Echos and Dots merely started the process and asked their owners for confirmation, but we hope it serves to draw attention to the risks associated with an always-on and always-listening device. We’ve looked at how the technology has seemingly circumvented the normal privacy concerns of our own community, so it’s hardly surprising that this kind of incident catches the greater public completely unprepared. It’s one thing for the denizens of a hackspace to troll the owner of a Dot by adding embarrassing products to their wish list, but against a less-informed user who hasn’t worked out how to lock down the device’s purchasing abilities, it’s not too far-fetched to imagine a criminal attack.

Voice assistants are clearly going to become a ubiquitous feature of our lives, and it is inevitable that there will be more such unfortunate incidents which will serve to educate the public about their privacy before the technology reaches maturity. This particular story is definitely Not A Hack, though as our “Alexa” tag shows the devices have huge potential to bring a new dimension to our work. It’s up to all of us in our community to ensure that the voice assistant owners in our lives are adequately educated about them, and maybe resist the urge to say “Alexa, add all the Hackaday merchandise to my wish list!”.

CES2017: Dissolvable Support Material

January 7, 2017 by 20 Comments

Over the last year, it seems the next big thing in 3D printing is dual and multi-extrusion. This gets you multi-colored objects, but if you have the right filament, it also allows you to print objects that would otherwise be impossible to print. This week, Airwolf 3D announced their HydroFill water soluble support material. They had a few sample prints and a fish tank, and yes this stuff does dissolve in water quickly.

There were a few problems with dissolvable support material in the past. PVA is water soluble, but it doesn’t print well. HIPS can be dissolved in limonene, but the resulting goo is toxic. Airwolf’s HydroFill beats both of these filaments, and the prints compare well to what E3D showed off with their Scaffold filament recently.

Check out my video below where [Jack Licorish] goes over the characteristics of HydroFill.

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Yes, You Can Reverse Engineer This 74181

January 7, 2017 by 21 Comments

[Ken Shirriff] is the gift that keeps on giving this new year. His latest is a reverse engineering of the 74181 Arithmetic Logic Unit (ALU). The great news is that the die image and complexity are both optimized for you to succeed at doing your own reverse engineering.

74181-openedWe have most recently seen [Ken] at work explaining his decapping and reverse engineering process at the Hackaday SuperCon followed soon after by his work on the 8008. That chip is crazy with complexity and a die-ogling noob (like several of us on the Hackaday crew) stands no chance of doing more than simply following along with what he explains. This time around, the 74181 is just right for the curious but not obsessed. Don’t believe me? The 8008 had around 3,500 transistors while the friendly 74181 hosts just 170. We like those odds!

A quick crash course in visually recognizing transistors will have you off to the races. [Ken] also provides reference for more complex devices. But where he really saves the day is in his schematic analysis. See, the traditional ‘textbook’ logic designs have been made faster in this chip and going through his explanation will get you back on track to follow the method behind the die’s madness.

[Ken] took his own photograph of the die. You can see the donor chip above which had its ceramic enclosure shattered with a brisk tap from a sharp chisel.

Disposable Camera Coil Gun!

January 7, 2017 by 12 Comments

Some of the most enjoyable projects tend to have the terrible drawback of also having the most potential to cause bodily harm, like getting zapped by the capacitor when digging into a disposable camera. But often — if you’re careful — this curiosity pays off and you wind up learning how to make something cool like this coil gun from a camera flash’s capacitor. This handheld launches a small nail, and is packed in a handheld form factor with a light switch trigger.

[LabRatMatt] dispels any illusions of potential harm upfront and then repeatedly urges caution throughout his detailed guide. He breaks down the physics at work while maintaining a lighthearted tone. This coil gun uses a capacitor and charging circuit ripped from a disposable camera — [LabRatMatt] decided to double up with another capacitor that he had on hand from a previous project. The coil was repurposed from an old doorbell, but make sure to use a few hundred windings if you make your own coil. A light switch ended up being suitable for a trigger since it is able to handle the voltage spikes.

When assembled, it almost looks like something you’d expect to see in a post-apocalyptic wasteland, but it works!

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