Brighten Your Day with Motion Controlled Cabinet Light

[Thomas Snow] found himself in a bit of a pickle. His kitchen lights didn’t adequately light his counter-tops. So instead of inventing a light bending device that could warp space-time enough to get the light where it needs to go, he decided to take the easy road and installed a motion controlled LED strip under the cabinets.

Now, these aren’t just any ‘ol motion control lights. Not only is [Thomas] able to turn the lights on and off with a wave of his hand, he can control the brightness as well. He’s doing the magic with an ultrasonic range sensor and PIR sensor. An ATTiny85 ties everything together to form the completed system.

The PIR sensor was incorporated because [Thomas] didn’t want to bug his pets with the 40kHz chirp from the ultrasonic sensor. So it only comes on when the PIR sensor sees your hand. Be sure to check out [Thomas’s] project for full source and schematics.

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Lonely? Build Yourself a Chess Robot!

[Oriol Galceran] has constructed an interesting robotic chess player for his end of school project. It’s called the ChessM8, and is an impressive feat considering [Oriol] is only 17!  He’s using an Arduino Mega that connects to the host PC via a Python script.

The AI can be any chess engine that uses the Universal Chess Interface protocol, which [Oriol] points out that most of them do.  We’ve seen other chess robots here before, along with others that you can play on your wall and uses Nixie Tubes. But [Oriol’s] build is the largest of them all.

He says there’s a network of REED switches under the chess board to detect when a piece is present or not. It would be interesting to know how he dealt with debouncing issues, and if Hall Effect sensors might have been a better choice. Let us know in the comments how you would detect the chess piece.

And be sure to check out the video below to see the chess robot in action.

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Ask Hackaday: The Many Uses of Microwaves

When most think of a microwave, they think of that little magic box that you can heat food in really fast. An entire industry of frozen foods has sprung up from the invention of the household microwave oven, and it would be difficult to find a household without one. You might be surprised that microwave ovens, or reactors to be more accurate, can also be found in chemistry labs and industrial complexes throughout the world. They are used in organic synthesis – many equipped with devices to monitor the pressure and temperature while heating. Most people probably don’t know that most food production facilities use microwave-based moisture solids analyzers. And there’s even an industry that uses microwaves with acids to dissolve or digest samples quickly. In this article, we’re going to look beyond the typical magnetron / HV power supply / electronics and instead focus on some other peculiarities of microwave reactors than you might not know.

Single vs Multimode

The typical microwave oven in the millions of households across the world is known as multimode type. In these, the microwaves will take on typical wavelike behavior like we learned about in physics 101. They will develop constructive and destructive interference patterns, causing ‘hot spots’ in the cavity. A reader tipped us off to this example, where [Lenore] uses a popular Indian snack food to observe radiation distribution in a multimode microwave cavity. Because of this, you need some type of turntable to move the food around the cavity to help even out the cooking. You can avoid the use of a turn table with what is known as a mode stirrer. This is basically a metal ‘fan’ that helps to spread the microwaves throughout the cavity. They can often be found in industrial microwaves. Next time you’re in the 7-11, take a look in the top of the cavity, and you will likely see one.

Multimode microwaves also require an isolator to protect the magnetron from reflected energy. These work like a diode, and do not let any microwaves bounce back and hit the magnetron. It absorbs the reflected energy and turns it into heat. It’s important to note that all microwave energy must be absorbed in a multimode cavity. What is not absorbed by the food will be absorbed by the isolator. Eventually, all isolators will fail from the heat stress. Think about that next time you’re nuking a small amount of food with a thousand watts!

Single Mode microwaves are what you will find in chemistry and research labs. In these, the cavity is tuned to the frequency of the magnetron – 2.45GHz. This allows for a uniform microwave field. There is no interference, and therefore no hot or cold spots. The microwave field is completely homogenous. Because of this, there is no reflected energy, and no need for an isolator. These traits allow single mode microwaves to be much smaller than multimode, and usually of a much lower power as there is a 100% transfer of energy into the sample.  While most multimode microwaves are 1000+ watts, the typical single mode will be around 300 watts.

single vs multimode cavity

Power Measurement

Most microwave ovens only produce one power level. Power is measured and delivered by the amount of time the magnetron stays on. So if you were running something at 50% power for 1 minute, the magnetron would be on for a total of 30 seconds. You can measure the output power of any microwave by heating 1 liter of water at 100% power for 2 minutes. Multiply the difference in temperature by 35, and that is your power in watts.

There are other types of microwaves that control power by adjusting the current through the magnetron. This type of control is often utilized by moisture solids analyzers, where are more precise control is needed to keep samples from burning.

Have you used a microwave and an arduino for something other than cooking food? Let us know in the comments!

Thanks to [konnigito] for the tip!

Reach Out and Touch Someone with WiFi Photo Booth

[kitesurfer1404] put together a nice looking vintage photobooth with WiFi capability. He’s using an arduino to monitor the state of the buttons, LED lighting control, seven segment display AND the DSLR camera. He then uses a Raspberry Pi to control imagine processing and to provide scaling and other effects, which can take up to 20 seconds per image. The Pi runs in WiFi Access Point mode, so anyone with a WiFi capable device can connect to the photo booth and view the images.

We’ve seen some interesting twists on photo booths before. But [kitesurfer1404’s] vintage style makes his stand out all on its own. He designed the graphics with Inkscape and printed them on thick paper. He then soaked the graphics in tea for several hours and dried then for several more days to get that nice rustic look.

Be sure to check out [kitesurfer1404’s] site for full details and an assortment of high resolution images of his project.

Ultimate Remote is Ultimate

[Joedefa] had a Griffin Beacon Universal Remote that was collecting dust, and decided that it needed to stop collecting dust. He had a growing number of wireless devices in his house and found himself in need of a remote to control them all. The Griffin Beacon fit the bill, but most of his lights and outlets were RF controlled. So he did what hackers do best… broke out the screw driver and soldering iron and rewired it!

[Joedefa] is using an Attiny85 as the brains between an infrared LED and a RF transmit module (if anyone can identify the source of this module, please let everyone know in the comments).  A pair of red and green LEDs lets him know if the remote has received commands successfully.

It’s always nice to see a discontinued product made useful once more with a little ingenuity and an Arduino some hacking skill. Hat’s off to [Joedefa] for a righteous hack!

Quadcopter Plane Transformer is Awesome

Is it a quadcopter? A plane?  No, it’s both! [Daniel Lubrich] is at it again with a vertical take off and landing transformer he calls the SkyProwler.

The SkyProwler uses a switch blade type mechanism to move from quadcopter mode to plane mode. The wings can be detached to make it a normal quad that has all the typical bells and whistles. It can follow you around with GPS, fly autonomously via way points, and has this cool gimbal mechanism that keeps the GoPro stable as the drone pitches in flight, allowing for a better video experience.

[Dan’s] ultimate goal is a full size passenger model called the SkyCruiser, which uses the same switchblade transformation mechanism as his much smaller SkyProwler. Be sure to check out the video below if you haven’t already, and let us know of any quadcopter / plane hybrids of your own.

Correction: We previously associated [Daniel Lubrich] with the ATMOS program. This was in error and has been removed from the article. The ATMOS UAV is a separate project which we previously covered.

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The One Million Dollar Scope Teardown

The Labmaster 10-100zi Oscilloscope is one of the fastest scopes in the world, coming in at a blistering speed of 100GHz with up to 240 Giga samples per second in real time. The scope is made by Teledyne LeCroy, and uses a frequency interleaving technology perfected by LeCroy, which allows it to provide a single 100GHz channel, or two 33GHz channels and a single 65GHz channel. The price tag? One million dollars.

[Shahriar] takes us inside the Teledyne Lecroy factory in Chestnut Ridge, NY where these scope are manufactured, and gives us the grand tour. First, an engineer describes the interleaving frequency technique that allows the lightning fast sample rates. Then they actually tear the million dollar scope down for our viewing pleasure. And if you still want more, they put it back together and run some tests to push the scope to its far reaching limits. Lastly, [Shahriar] takes us on a tour of the plant where the scopes are built.

It’s a lengthy video, so grab your favorite beverage and tuck in! It’s shocking how fast technology progresses. Just about 18 months ago [Shahriar] took us through the then reigning champion of scopes the Agilent DSA-X 96204Q which capturered 160GS/s at 62GHz.

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