Building A Coffee Roaster From Junk

July 27, 2012 by Mike Szczys 10 Comments

[Rxdtxd] has tried his hand at roasting coffee beans in a frying pan. It works but he can only roast small batches at once. What he really needed was a large-scale roaster that would have no problem with a few pounds of the green beans all at once. He ended up building this large-scale coffee roaster out of junk parts.

The vessel which holds the beans is the drum from a top-loading washing machine. It was headed for the junk pile, but the fully-enclosed drum is perfect for this purpose. After acquiring it [Rxdtxd] set out welding a frame that would hold either side by the pivot points. He used a geared motor to automate the process. The output shaft on the gear box is meant to drive a chain, but he just welded some pieces onto the gear to use as a coupling.

In the picture above he’s giving the roaster a thorough testing with about ten pounds of beans. A portable gas stove placed below the rotating drum supplies the heat. After the beans have reached the desired darkness he pours them out into a large skillet to cool. Take a peek at the roasting action in the clip after the break.

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Lab Robot Demonstrates Mastery Of Culturing And Other Tasks

July 27, 2012 by Mike Szczys 12 Comments

Lab work is a pretty good job. But sometimes being around hazardous samples, or completing tedious and repetitive tasks leave scientists looking for a different way. This robot seems to know its way around a lab. The folks behind it claim it’s more precise than veteran lab technicians, and that it can complete the tasks in half the time.

After watching the video (embedded after the jump) we’re quite impressed. The dexterity shown by the system illustrates care down to the tiniest of details. This is because everything the robot works with has been passed through a 3D scanner in order to establish a virtual model. This way the training is done in the computer. The robot can be run though any number of scenarios before it actually starts working with infectious materials like the influenza virus and other not-so-nice microbes.

What we’d really like to know is what kind of visual feedback system is being used.

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Gaining Low-level SPI Access On The Raspberry Pi

July 27, 2012 by Mike Szczys 7 Comments

Raspberry Pi - rpi

We’ve seen a ton of projects that interface hardware with the Raspberry Pi. But they usually depend on bit-banging. That means they toggle the pins in software to match a specific protocol. The thing is that the beefy Broadcom SoC that anchors the board has a lot of built-in peripherals that are just waiting to be used instead of bit banging. In this case, it’s the hardware SPI peripheral which can be accessed via the bcm2835 library for RPi.

One of the things that would have really complicated this process is the pin mapping between the Broadcom chip and the RPi GPIO header. Since not all pins are broken out, it was either luck or good design forethought that made all of the SPI0 pins from the chip available on the RPi breakout header. The library page (linked above) explains this well. But if you’re looking for more of a working example check out [EngineerByNight’s] project with adds an accelerometer using hardware SPI.

A Much Larger Rainbow Board Of Many Ping Pongs

July 27, 2012 by Mike Szczys 11 Comments

[George] started with an 8×8 grid, but just couldn’t help himself from upscaling to this 32×16 pixel ping pong ball display. That’s right, It’s a 512 pixel array of fully addressable RGB LEDs diffused with one ping pong ball each.

We featured the predecessor to this project back in January. That one was an 8×8 display using a Rainbowduino as the controller. [George] took what he learned from that build and expanded upon it. The larger display is modular. Each module starts as an 8×8 grid which connects back to the Arduino using a breakout shield with some Ethernet jacks used as quick connects. The LEDs are driven by 595 shift registers, with transistors which protect the logic chips from the currents being switched.

He had a lot of help soldering all the connections for the display and ended up bringing it to show off at the Manchester mini maker faire. See it in action in the video after the break.

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Force Carbonating Root Beer With Dry Ice

July 27, 2012 by Mike Szczys 49 Comments

[Paul] is sick and tired of his homemade root beer being flat. He analyzed the problem with his carbonation techniques and ended up with a method of force carbonating beverages using dry ice.

He starts of by discussing the various methods that are used to carbonate beverages. There’s the old yeast and sugar trick that takes place inside of a sealed bottle. But this takes time, and if you don’t calculate the mixture correctly you could have over or under carbonated bottles (or exploding bottles in the case of glass beer bottling). [Paul] himself has tried the dry ice in a cooler full of root beer method. The problem is that the cooler isn’t pressurized so the carbonation level is very low. You need to have cold temperatures, high pressure, and the presence of carbon dioxide all at the same time in order to achieve high levels of carbonation.

His solution is to use a 60 PSI safety valve. He drilled a hole in a plastic bottle cap to receive the valve. He then drops a few chunks of dry ice in and seals it up. The valve will automatically release the gas as the pressure builds past the 60 PSI mark. What he ends up with is a highly carbonated beverage in a matter of minutes.

If you don’t mind spending some cash you can use an adjustable pressure regulator. This way you can carbonate just about anything.

[Thanks Steven]

Make A Cardboard Bookshelf In Less Than A Day

July 27, 2012 by Mike Szczys 8 Comments

Lucas came up with a real winner when upcycling cardboard to use as a bookshelf. It’s visually pleasing, can be built basically for the cost of glue and a mounting brackets, and you don’t have to feel bad if you decide to get rid of it later on.

What he saved in raw material cost he spent in labor. There are 23 different layers of cardboard that went into the project, not including the spacer squares between each piece. The vast majority of the time spent in the clip after the break shows a fast-time video of him cutting out the layers. It apparently took about eight hours of cutting, and we’d image he’s got a claw of a hand after all of that work.

This is hanging from a single L bracket positioned in the square opening with two nails to keep it level. We’d suggest including a better mounting technique in your design. If you have some ideas about this please let us know in the comments.

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Designing A Quadcopter Brain PCB

July 27, 2012 by Mike Szczys 6 Comments

When working on his quadcopter project [Matt] decided it would be best to build a robust controller for the device. He had never sent off a PCB design for fabrication, but took the plunge and ended up with a compact and reliable PCB on the first try.

One of the first things that comes to mind when we hear about quadcopter controllers are the feedback sensors. The accelerometers which are used for these projects generally come in a DFN or QFN package. This means there are no legs. Instead the chip has pads on the bottom of the package making it a lot more difficult to solder. [Matt] side-stepped this issue by using an IMU board which already has the sensors in place and offered a 0.1″ SIL pin header to use as an interface. This is simple to roll into the design, along with all of the other connectors for motor control, power, etc. He grabbed a copy of Eagle Lite to do the layout, and used OSH Park to get the boards fabricated. He was surprised that everything worked on the first try. Thanks to his planning it fits inside of a plastic food container where it should be able to ride out most minor crashes with ease.