An Astronomical Observatory For Your Front Yard

February 11, 2017 by Jenny List 11 Comments

[Barry Armstead] is an astronomy enthusiast who built his own observatory in his front yard, in Canberra, Australia. It was a fine observatory as home-made observatories go, but he describes it as being small and cramped. His replacement was on an entirely different scale though, a building created by hand and which no doubt many readers would be pleased to own.

His design started with a cardboard model, and has a downstairs room upon which sits a rotatable dome with two sliding sections to form the observation window. The original observatory’s concrete pillar on which the telescope mount stood remained post-demolition, and a larger concrete pad was laid. There followed the assembly of a steel frame with a skeletal dome able to rotate on rollers, followed by cladding with steel sheet. The dome cladding was done in segments marked against the dome steelwork and cut to shape.

The final building has a fully finished interior downstairs, plus a rustic staircase to the upper deck. The concrete post has been extended, and now carry’s [Barry]’s telescope which he controls not with his eye clued to an eyepiece like the astronomers of old, but from a computer at the adjacent desk. The full construction details are on the observatory’s web site, though since it seems in danger of disappearing due to an expired hosting account we’ll also give you a Wayback Machine link direct to the relevant page. Meanwhile he offers a tour in a video we’ve placed below the break. Even a non-astronomer would find this an asset in their garden!

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The Mother Of All Paper Cuts

February 11, 2017 by Brian Benchoff 41 Comments

A Dremel is a fantastically handy tool to have around the workbench, but there is one glaring and obvious downside: you will always run out of cut-off discs. if you’re trying to break into a fancy snap-fit enclosure that has been inexplicably glued together, you’ll invariably need to run down to the hardware store to shell out some cash for a tiny tube of cut-off disks.

[KB9RLW] has the answer to this problem. He’s cutting wood and plastic with paper discs spinning at 35,000 RPM.

The paper used for this application is just a piece of junk mail or heavy, probably glossy card stock. After poking a hole in this piece of paper, tracing a circle with a homemade compass, and cutting out the cutting disk with a pair of scissors, this cut-off disc is easily mounted in the standard Dremel mandrel.

The test cut [KB9RLW] shows us is on a plastic wall wart that’s a glued together, snap-fit mess. The paper cut-off wheel makes short work of this nigh-impenetrable brick of plastic, revealing the electronic goodies inside. This cut-off wheel will also cut through small bits of wood, like a bit of molding.

After cutting halfway through the wooden molding, the paper disc quickly disintegrates — this is the same behavior we last year when this trick was being used on a table saw. But any home should get more than enough junk mail for a steady supply of paper Dremel cut-off discs. While this new attachment for your fancy rotary tool won’t last very long, it is a very expedient way to get into bits of electronics without paying Dremel several cents for a cut-off disc.

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Brake Light Blinker Does It With Three Fives

February 11, 2017 by Bryan Cockfield 35 Comments

Sometimes you use a Raspberry Pi when you really could have gotten by with an Arudino. Sometimes you use an Arduino when maybe an ATtiny45 would have been better. And sometimes, like [Bill]’s motorcycle tail light project, you use exactly the right tool for the job: a 555 timer.

One of the keys of motorcycle safety is visibility. People are often looking for other cars and often “miss” seeing motorcyclists for this reason. Headlight and tail light modulators (circuits that flash your lights continuously) are popular for this reason. Bill decided to roll out his own rather than buy a pre-made tail light flasher so he grabbed a trusty 555 timer and started soldering. His circuit flashes the tail light a specific number of times and then leaves it on (as long as one of the brake levers is depressed) which will definitely help alert other drivers to his presence.

[Bill] mentions that he likes the 555 timer because it’s simple and bulletproof, which is exactly what you’d need on something that will be attached to a motorcycle a be responsible for alerting drivers before they slam into you from behind.

We’d tend to agree with this assessment of the 555; we’ve featured entire 555 circuit contests before. His project also has all of the tools you’ll need to build your own, including the files to have your own PCB made. If you’d like inspiration for ways to improve motorcycle safety in other ways, though, we can suggest a pretty good starting point as well.

The Smartest Computer Was On Star Trek

February 11, 2017 by Al Williams 31 Comments

There have been a lot of smart computers on TV and movies. We often think among the smartest, though, are the ones on Star Trek. Not the big “library computer” and not the little silver portable computers. No, the smart computers on Star Trek ran the doors. If you ever watch, the doors seem to know the difference between someone walking towards it, versus someone flying towards it in the middle of a fist fight. It also seems to know when more people are en route to the door.

Granted, the reason they are so smart is that the doors really have a human operating them. For the real fan, though, you can buy a little gadget that looks like an intercom panel from the Enterprise. That would be cool enough, but this one has sound effects and can sense when someone walks into your doorway so they can hear the comforting woosh of a turbolift door.

Of course, for the real hacker, that’s not good enough either. [Evan] started with this $25 gadget, but wanted to control it with an Arduino for inclusion in his hackerspace’s pneumatic door system. He did a bit of reverse engineering, a bit of coding, and he wound up in complete control of the device.

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How To Fix Your Broken Onion Omega2

February 11, 2017 by Brian Benchoff 55 Comments

A decade ago, while RISC architecture was busy changing everything and people were wearing Utilikilts without beards, hackers were doing something amazing. They repurposed off-the-shelf routers and turned them into what we would now call the Internet of Things. Need to set up a PBX? A Linksys router will do it. Want to drive a remote control car over the Internet? It’s your old friend, WRT54G.

Now that the Internet of Things is a thing, a few companies have realized people will buy bare bones router chipsets. It’s like an Arduino, or something, and it connects to the Internet. We’ll sell a million. Get Indiegogo on the phone.

The Onion Omega2 launched on Kickstarter last year, and so far has seen some success. They’ve shipped their units, and people are generally happy with them. One thing that wasn’t mentioned in the Kickstarter was the fundamental problem with the design. The pins on this seemingly breadboard-compatible dev board have a pitch of two millimeters. Horribly broken. Huge mistake. Terrible deal. Not the best people we have working on this.

The Onion Omega2 won’t fit in a breadboard, but Onion does offer a breakout ‘expansion dock’ for $15 USD. There’s a better, cheaper solution, though. You can complain about it on Hackaday.io’s Hack Chat. That’s what [zach] did, and a few minutes later, [davedarko] whipped up a quick PCB design to convert the 2mm header to the much more logical 0.1 inch header. Imperial units win once again.

After sending three dollars and twenty cents to OSHPark, [zach] had his pin adapters in hand. A few minutes with a soldering iron, and the Onion Omega2 is made compatible with every breadboard ever made.

If you have an Onion Omega2 and would like a really cool hexagonal sticker, here’s the project on OSHPark.

Press Button, Receive Hackspace WiFi Code

February 10, 2017 by Jenny List 18 Comments

When you are running a hackspace, network security presents a particular problem. All your users will expect a wireless network, but given the people your space will attract, some of them are inevitably going to be curious enough to push at its edges. Simply plugging in a home WiFi router isn’t going to cut it.

At Santa Barbara Hackerspace they use Unifi access points on their wireless network, and their guest network has a system of single-use codes to grant a user 24-hour access. The system has the ability to print a full sheet of codes that can be cut individually, but it’s inconvenient and messy. So the enterprising hackspace members have used a Raspberry Pi and a receipt printer to deliver a single code on-demand at the press of a button.

The hardware is simple enough, just a pull-up and a button to a GPIO on the Pi. Meanwhile the software side of the equation has a component on both client and server. At the server end is a Python script that accesses the Unifi MongoDB database and extracts a single code, while at the client end is another Python script that reacts to a button press by calling the server script and printing the result. It’s a simple arrangement that was put together in an evening, but it’s an effective solution to their one-time WiFi access needs.

It’s a temptation as a hackspace to view all of your problems as solvable in one go with the One Piece Of Software To Rule Them All, and as a result some spaces spend a lot of time trying to hack another space’s effort to fit their needs or even to write their own. But in reality it is the small things like this one that make things work for members, and in a hackspace that’s important.

Does your space have any quick and simple projects that have automated a hackspace process? Let us know in the comments.

Thanks [Swiss] for the tip.

Huge Interactive Crossword

February 10, 2017 by Anool Mahidharia 7 Comments

Give kids some responsible and challenging tasks, and you’d be surprised at the results. The “Anything Goes” exhibit at the National Museum in Warsaw was aimed as a museological and educational experiment. A group of 69 children aged 6–14 was divided into teams responsible for preparing the main temporary exhibition at the museum. Over six months, they worked on preparing the exhibition during weekly four-hour meetings. They prepared scripts, provided ideas for multimedia presentations, and curated almost 300 works for display. One of those was [Robert Mordzon]’s Giant Interactive Crossword.

The build is in two parts. The letter tiles, which have embedded RFID tags, obviously look like the easiest part of the build. The table, looking at the video (after the break), probably needed a lot more effort and labour. It is built in two halves to make construction easier. There are a 130 boxes that need to be filled in with the right letters to complete the crossword. Each box contains a bunch of electronics consisting of an Arduino Nano, a RFID Reader and a bunch of sixteen WS2812B LEDs, all assembled on a custom PCB. Do the math, and you’ll figure out that there’s 2080 LEDs, each capable of sipping 60 mA at full brightness. That’s a total current requirement of almost 125 amps at 5 V. Add in all the Arduino’s, and [Robert] needed a beefy 750 W of power, supplied via four switch mode power supplies.

Each Arduino Nano is a slave on the I²C bus. The I²C master is an Arduino Mega 2560, which in turn communicates with a computer over serial. When a box is empty, the LEDs are dim, when a wrong letter is placed, they turn Red, and when the right letter is placed, they turn Green. If a word gets completed, a special word animation is played. This information is also passed on to the computer, which then projects an animation related to the word on a giant wall screen. Upon the crossword getting completed, the table erupts in to a sound (via the computer) and light “disco” show and also reveals the main motto of this section of the exhibit – “Playing the Hero”.

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