Pi Network Attenuators: Impedance Matching For The Strong Of Signal

April 20, 2017 by Jenny List 29 Comments

If you catch a grizzled old radio amateur propping up the bar in the small hours, you will probably receive the gravelly-voiced Wisdom of the Ancients on impedance matching, antenna tuners, and LC networks. Impedance at RF, you will learn, is a Dark Art, for which you need a lifetime of experience to master. And presumably a taste for bourbon and branch water, to preserve the noir aesthetic.

It’s not strictly true, of course, but it is the case that impedance matching at RF with an LC network can be something of a pain. You will calculate and simulate, but you will always find a host of other environmental factors getting in the way when it comes down to achieving a match. Much tweaking of values ensues, and probably a bit of estimating just how bad a particular voltage standing wave ratio (VSWR) can be for your circuit.

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A Robot Arm With The Tender Grip Of An Octopus

April 19, 2017 by Jenny List 30 Comments

If you’ve ever experimented with a robot gripper, you’ll know that while it is easy to make an analogue of the human ability to grip between thumb and forefinger, it is extremely difficult to capture the nuances of grip with the benefit of touch feedback to supply only just enough of the force required to grip and hold an object. You as a human can pick up a delicate eggshell without breaking it using the same hand you might use to pick up a baseball or a cricket ball, but making your robot do the same thing is something of an engineering challenge.

The robot gripper is something that has exercised the minds of the folks at Festo, and the solution they have arrived at is as beautiful as it is novel. They have produced a gripper based upon the action of an octopus tentacle, though unlike the muscle of the real thing they’ve created a silicone tube which bends inwards when inflated. Its inner surface is covered with octopus-like suckers, some of which can be activated by a vacuum. The result is a very capable and versatile gripper which due to its soft construction is ideal for use in environments in which robots and humans interact.

They’ve put up a slick video showing the device in action, which we’ve put below the break. Tasks such as gripping a rolled-up magazine or a plastic bottle that would tax more conventional grippers are performed faultlessly.

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Hackaday Prize Entry: GoKart Tank

April 18, 2017 by Jenny List 26 Comments

There is probably something in all of us that yearns to drive a tank, just once. Most of us will probably never fulfill it, in fact, unless we work in farming or construction we’re unlikely to even drive a skid-steer vehicle of any type. But that doesn’t mean we can’t have a go at building one ourselves, as [samern] is doing with his Hackaday Prize entry.

The GoKart Tank has a chequered history, as a build that started as an internal combustion go-kart, became a half-track, and eventually the fully tracked electric vehicle we see today. It has a wooden frame, two 1KW electric scooter motors, and tracks made from IntraLox modular plastic industrial conveyor belt parts. This last choice is particularly interesting because even though it isn’t designed for use as a track it is designed for heavy-duty service and could offer a component source for other tracked vehicle projects.

What you see is a working tracked vehicle, but it is not without problems. The electric motors are only powerful enough to move a child, so there are plans to return it to internal combustion power. We can, however, see it working, as you can watch the video of it we’ve put below the break.

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A Smart Switch Board For The ESP8266

April 17, 2017 by Jenny List 20 Comments

With a plethora of IoT projects and inexpensive commercial smart light fittings and mains switches appearing, you might be forgiven for thinking that another offering in this crowded marketplace would be superfluous. But there is always room for improvement in any field, and in this particular one [Xose Pérez] has done just that with his Espurna board.

This board is a very well executed ESP8266 mains relay, with an on-board mains power supply and power monitoring. It was designed with his Espurna (“Spark” in Catalan) custom firmware in mind, which offers support for Alexa, Domoticz, Home Assistant and anything that supports MQTT or HTTP REST APIs.

Best of all, it’s a piece of open source hardware, so you can download everything you need from his GitHub repository to create your own. For the ultimate in convenience you can even order the PCB ready-made from OSH Park.

As a demonstration of the Espurna board in a real application, he’s produced a smart socket project neatly enclosed in a wall-wart style box with an inbuilt Euro style plug and socket.

We’ve featured [Xose]’s work several times before here at Hackaday, he’s something of an IoT wizard. Most recently there was his work with Alexa and the ESP8266, but before that was his MQTT LED array for his laundry monitor.

This Binary Keyboard Is For ASCII Purists

April 17, 2017 by Jenny List 48 Comments

So, you’re a keyboard enthusiast. The ‘board that came from Dell, HP, or whoever made your computer is just not for you. You have an ancient IBM, a decal-free Das Keyboard, or another similarly esoteric text input device. Your typing can be heard three blocks away as the unmistakable clack of bent-spring switches reverberates around you, but you don’t care because you’re in the Zone.

No keyboard can be as high-end as the one you already have, your position in the hierarchy of text entry is assured. But then along comes [Chris Johnston] with his project, and suddenly your desktop looks very cluttered. It’s a binary keypad with only a 0 key, a 1 key, and an OLED display. All input is as a series of binary bytes, so as a hardcore binary typist you’ll need to know your ASCII.

Behind the keys is an Arduino Pro Micro acting in USB HID mode, and running the code you can download from the GitHub link above. It’s a gloriously pointless input device, but we’re sure you’ll agree it has something of the 00110001 00110011 00110011 00110111 about it.

If you think you may have seen this before on Hackaday then you’re not quite right. We have had a binary keypad in the past, but that one had a return key and thus had three keys. This one’s a 2-key ‘board for binary purists.

[via /r/mechanicalkeyboards/]

Hackaday Prize Entry: Another Internet Button

April 17, 2017 by Jenny List 7 Comments

It’s long been a staple of future-gazing, the idea that we will reach a moment at which all of life’s comforts can be summoned at the press of a button. Through the magic of technology, that is, without the army of human servants with which wealthy Victorians surrounded themselves to achieve the same aim.

Of course, to reach this button-pressing Nirvana, someone has to make the buttons. There are plenty of contenders for the prize of One Button To Rule Them All, the one we’ll probably have seen the most of is Amazon’s Dash. Today though we’re bringing you another possibility. [Hendra Kusumah]’s A.I.B. (Another IoT Button) is as its name suggests, a button connected to the Internet. More specifically it’s a button that connects to IFTTT and allows you to trigger your action from there.

Hardware wise, it couldn’t be simpler. A button, a Particle Photon, some wires, and a resistor. Then install the code on the board, and away you go. With a small code change, it also works with an ESP8266. That’s it, it couldn’t be simpler. You might ask where the fun in that lies, but you’d be missing the point. It’s the event that you trigger using the button that matters, so why make creating the button a chore?

We’ve shown you many IoT buttons, just a couple of posts are this ESP8266 button and a look at the second-generation Amazon Dash.

The Complex Issue Of Hackspace Donations

April 14, 2017 by Jenny List 74 Comments

More than one member of the Hackaday team has significant involvement in a hackspace, as member, director, or even founder. We talk about hackspaces quite rarely on these pages though, not because we don’t have anything to say on the matter but because even when we write in general terms our fellow members invariably think it’s all about them rather than the hackspace world at large.

For once I’m going to break the silence, and not only talk about hackspaces, but talk about my own hackspace in specific terms. Because, fellow Oxford Hackspace members, this isn’t about you personally though I’m using our home to illustrate a point. The topic is a thorny issue that must affect all spaces, that of donations of physical items. People want to help their hackspace, they have a pile of what they consider to be good stuff, and when they’re having a clear-out they make a donation. But, as we all know, “one man’s trash is another man’s treasure” and vice-versa. Continue reading “The Complex Issue Of Hackspace Donations” →