Hackaday Links: September 8, 2013

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“I’m sorry Dave, I’m afraid I can’t open the dorm room door.” Does your dorm room have a peephole? Take [pjensen's] lead and turn it into a mini HAL 9000 using a red LED.

Mix a little work in with your hobby skills. [Vittore] needed to build a video looper to drive some TV screens for a Hotel contract job. He grabbed a Raspberry Pi and got to work. The final product (translated) even uses a shared folder on the hotel’s network as the source slides.

We’re not sure if anyone noticed last Monday (it was Labor Day in the U.S.).  We had a little fun with coffee themed posts. [Tom] wrote in to remind us about the HTCPCP: Hyper Text Coffee Pot Control Protocol. If you don’t have time to read it all, he suggests you don’t miss his favorite, error code 418.

Maybe funny reading isn’t your thing right now, but we have some more helpful stuff to offer. Check out [John Chandler's] Commandments for using PIC microcontrollers from a few years back.

[Andy] has some old smart phones which he is using in his projects. His beef with the touchscreens is that there’s no tactile feedback. Since these are going to be dedicated displays he’s outlining the touch controls with tape to let your finger know what it’s doing.

If you’re living in your first home in America there’s a really good chance it’s a 1950’s ranch house considering how many of them were built after World War II. Bring its infrastructure into the information age with a cable retrofit. [Andrew Rossignol] just did so and posted a lot of pictures of the process.

If you liked [Ken Shirriff's] post about the Sinclair Scientific Calculator we think you’ll love his continuation of a Z80 reverse engineering series.

Use your new-timey printer to make an old-timey camera

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Here’s something to show people who don’t realize the power of 3D printing. This pinhole camera has one moving part which reveals the pinhole, letting in light to expose the 4×5 film inside.

It’s a near perfect roundup of all the qualities a 3D printer has to offer. The build centers around a 4×5 film holder which can be acquired used or as surplus. This drives home the concept of having the power to replace parts (in this case the entire camera) that fit with existing pieces (the film holder). The picture above is big enough that you can see the layers on the pyramid shape, but the structural pieces around the frame also let the uninitiated see that you can print more than just solid blocks. And finally, since it’s up for download on Thingiverse its a good example of how the printing community shares and builds on each others’ work.

Does it take quality photos? We have no idea. So far we didn’t see any example pictures. But really, if you’re looking for top quality you might want to build your own digital camera. Here’s one that uses a 14 megapixel sensor.

We’re Hiring

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The title says it all. We need more writers to keep the fresh hacks coming, now’s your chance to apply for the job.

UPDATE: Thank you for all of the applications. I have made the first round of offers to a select few. Narrowing it down to a handful was difficult as so many highly qualified, avid readers sent in applications. You are still welcome to submit an application which we’ll keep on file, but I don’t anticipate making any more offers at this time.

[Read more...]

BREWSTER fetches your beer automatically

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Afraid that if you leave the room you’ll miss the best play of the game? Now you don’t need to move your rear end in order to grab the next brewski. BREWSTER was developed to fetch cold beers from the fridge and deliver them to you automatically.

The robot started as a roomba but has been heavily repurposed with the addition of a mechanical arm on top of the chassis. This not only lets BREWSTER grip a can of beer, but it can first open the mini fridge and reach far enough inside to get one from the back. This requires no modification to the refrigerator, but the low clearance of the roomba does call for a mini-fridge sitting at floor level. Check out a demo run in the video after the break. We think the current version is running on a pre-coded route; this project is just waiting for a spin-off that has mapping and machine vision.

The alternative to this single can delivery would be to make the entire icebox into a robot.

[Read more...]

Web connectivity and other addons for an automatic schnauzer feeder

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[Ben Miller] and his dad combined forces to create this automatic dog feeder. It not only keeps their two schnauzers happy, but gives them peace of mind as they can double-check that he feeding happened by pulling up an image on the Internet. Make sure you make it through all three posts of the build to get the entire picture.

The project started with some research which turned up a project that used a commercially available automatic feeder. That one used Arduino, but because of the cost the board plus a WiFi shield is a bit high, [Ben] went with a Raspberry Pi and a USB WiFi dongle instead. The Pi is much more powerful and adds the functionality for capturing images via a webcam.

After a convoluted process of connecting the Pi to the existing button traces on the automatic feeder it was time to start coding. The system runs from a Perl script which monitors a Gmail account for remote commands (in addition to a regular feeding schedule). The final touch is a bit of mechanical engineering which splits the output into two bowls so the dogs each have their own serving.

We still use the Autodine we built several years back but its single-serving limitation has always kept a second version on our project list. Hopefully seeing a well-executed system like this will motivate us to get building!

The Nibbler: a 4-bit CPU built with 7400 logic

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Maybe we shouldn’t say “built” since [Steve Chamberlin] hasn’t actually heated up his iron yet. From the finished schematic above that is puzzling at first, until you realize the scope of the project. His Nibbler implements a 4-bit CPU using 7400 logic chips. Because he’s come up with the architecture himself he’s taking a lot of steps to check all of his work before committing to a PCB.

We linked to his category for the project which is still in progress. Most recently he wrote a program to prove that it’ll run on the hardware. That’s a feat considering this is still just a design idea. It was made possible because he wrote a simulator based on the design. The C++ tool simulates data and control buses and features a full set of debugging tools.

Careful testing of the design before the build is the best possible way to go. The simulator and debugging tools will be useful for software development even after the hardware is built. And testing before wiring is a must as these things get out of control quickly in terms of soldering complexity.

[via Dangerous Prototypes]

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