Easy Way To Listen To Cube Sats

[Bill Meara] has discovered an easy way to listen to amateur “cube-sat” satellites using a cheap SDR Dongle.

The DVB-T SDR Dongle comes in at a whopping thirteen bucks, and the highly sophisticated antenna (pdf) is made from a bit of copper wire and uses aluminum wire for the ground plane.

Once he had everything hooked up, [Bill] went to the Heavens Above website to see when satellites would be passing over him. He was able to lock onto the Prism Satellite, and then a couple other cube-sats that were launched from Russia and Istanbul.

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Hackaday Prize Entry: Saving Water with the Vinduino

[Reinier van der Lee] owns a vineyard in southern California – a state that is in a bit of a water crisis. [Reinier van der Lee] also owns an arduino and a soldering iron. He put together a project the reduces his water usage by 25%, and has moved it to open source land. It’s called the Vinduino.

water animationIts operation is straight forward. You put a water sensor in the dirt. You turn on the water. When the water hits the sensor, you turn the water off. This was not, however, the most efficient method. The problem is by the time the sensor goes off, the soil is saturated to the point that the plant cannot take it all up, and water is wasted.

The problem was solved by using three sensors. The lowest most sensor is placed below the roots. So it should never go off. If it does, the plant is not taking in all the water, and you can reduce the output. The two sensors above it monitor the water as it transitions through the soil, so it knows when to decrease the water amount and watering cycle times.

Be sure to check out the project details. All code and build files are available on his github under the GNU General Public License 3.0

The 2015 Hackaday Prize is sponsored by:

Manipulating Matter In A Digital Way

On a fundamental level a computer’s processor is composed of logic gates. These gates use the presence of electricity and lack thereof to represent a binary system of ones and zeros. You say “we already know this!” But have you ever considered the idea of using something other than electricity to make binary computations? Well, a team at Stanford University has. They’re using tiny droplets of water and bar magnets to make logic gates.

Their goal is not to manipulate information or to compete with modern ‘electrical’ computers. Instead, they’re aiming to manipulate matter in a logical way. Water droplets are like little bags that can carry an assortment of other molecules making the applications far reaching. In biology for instance, information is exchanged via Action Potentials – which are electrical and chemical spikes. We have the electrical part down. This technology could lead to harnessing the chemical part as well.

Be sure to check out the video below, as they explain their “water computer” in more detail.

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Inceptionism: Mind Blown by What Neural Nets Think They See

Dr. Robert Hecht-Nielsen, inventor of one of the first neurocomputers, defines a neural network as:

“…a computing system made up of a number of simple, highly interconnected processing elements, which process information by their dynamic state response to external inputs.”

These ‘processing elements’ are generally arranged in layers – where you have an input layer, an output layer and a bunch of layers in between. Google has been doing a lot of research with neural networks for image processing. They start with a network 10 to 30 layers thick. One at a time, millions of training images are fed into the network. After a little tweaking, the output layer spits out what they want – an identification of what’s in a picture.

The layers have a hierarchical structure. The input layer will recognize simple line segments. The next layer might recognize basic shapes. The one after that might recognize simple objects, such as a wheel. The final layer will recognize whole structures, like a car for instance. As you climb the hierarchy, you transition from fast changing low level patterns to slow changing high level patterns. If this sounds familiar, we’ve talked out about it before.

Now, none of this is new and exciting. We all know what neural networks are and do. What is going to blow your knightmind, however, is a simple question Google asked, and the resulting answer. To better understand the process, they wanted to know what was going on in the inner layers. They feed the network a picture of a truck, and out comes the word “truck”. But they didn’t know exactly how the network came to its conclusion. To answer this question, they showed the network an image, and then extracted what the network was seeing at different layers in the hierarchy. Sort of like putting a serial.print in your code to see what it’s doing.

They then took the results and had the network enhance what it thought it detected. Lower levels would enhance low level features, such as lines and basic shapes. The higher levels would enhance actual structures, such as faces and trees. ibisThis technique gives them the level of abstraction for different layers in the hierarchy and reveals its primitive understanding of the image. They call this process inceptionism.


Be sure to check out the gallery of images produced by the process. Some have called the images dream like, hallucinogenic and even disturbing. Does this process reveal the inner workings of our mind? After all, our brains are indeed neural networks. Has Google unlocked the mind’s creative process?  Or is this just a neat way to make computer generated abstract art.

So here comes the big question: Is it the computer chosing these end-product photos or a google engineer pawing through thousands (or orders of magnitude more) to find the ones we will all drool over?

The Shady World of Drone Racing

No one noticed the two men in the alley as the darkness of midnight approached – their long, black trench coats acting like a soldier’s camouflage.

“You got the goods?”

“Yeah, these are hot man…super fast..check this…”

The bark of a police siren broke their whispered conversation like a shattering glass, causing the two men to briefly freeze in their steps.

“Johnny B. got busted last week…did you hear?”

“No way man! What he get busted for?”

“Drone racing man…drone racing.”

Deep within the shadows of abandoned warehouses and dilapidated factories on the outskirts of Australian suburbia, the telltale buzz of numerous drones can be heard. Zipping to and fro at speeds upwards of 60km/h, these drones are not just flying. They’re racing each other. The operators use specialized FPV goggles that allow them to see the raceway in real time. This method, unfortunately, puts them on the wrong side of the law.

The dated laws governing drones in Australia are similar to those in the US, which were written for the radio controlled plane industry. While they technically forbid any flying outside of line-of-site, the Australian Civil Aviation Authority seems to be OK with the drone racing so long as it’s done indoors and poses no risk to people or property.

Know of any drone racing in your country? Is it legal? Do people do it anyway? Let us know in the comments.

We Have A Problem: 3D Printers Are Too Expensive

Hackaday, we have a problem. 3D printing is changing the world but it’s still too expensive to be embraced as a truly transformative technology.

With each passing year, the 3D printing industry grows by leaps and bounds. Food safe PLA is now the norm, with dissolvable and other exotic filaments becoming more mainstream.  New filaments are making it possible to print objects that were not possible before. New CAD software is popping up like dandelions, with each iteration giving novice users a friendly and more intuitive interface to design 3D models. As time marches on, and we look into its future, a vision of the 3D printing world is evident – its only going to get bigger.

3d printerImagine a future where a 3D printer is as common as an ink jet printer in homes all across the world.  A future where you could buy filament from the supermarket down the street, and pick up a new printer from any hardware store. A future where dishwashers, refrigerators and bicycles come with .stl files that allow you to print upgrades or spare parts. A future where companies compete to give the market easy-to-use printers at the cheapest price.

Is this future possible? Not until the technology changes. It’s too expensive, and that’s the problem you’re going to solve. How can you make a 3D printer cheaper? A cheap printer could change the game and make our future a reality.

Where do we need cost savings?

To get you going, here are some parts of common 3D Printers which think need to find cost-saving solutions.


Stepper motors are going to run you about $15 each. Is it possible to use cheaper DC motors with some type of position tracking while keeping the cost down?


Threaded rod is probably the cheapest way to move your XYZ axis. What about couplings and guide rods? Check out how this guy made a CNC out of parts from his local hardware store.


No arduino with Easysteppers here – too expensive. We’ve just seen a super cheap controller a few days ago. If we use something other than NEMA steppers, it will radically change the typical electronic controller for our super cheap 3d printer.


What is the cheapest way to melt and extrude plastic? What about using thermistors in place of thermocouples? Let’s think out of the box with this, and see if we can get away from the typical stepper motor based extruder. Remember, everything is low cost. If we have to sacrifice some resolution, that is OK.

So there you go. Let’s hear your input on the issue. We need to make 3D printers a lot more affordable and we want to hear any ideas you have on the topic in the comments below. Do you think this is in our future and why?

The 2015 Hackaday Prize is sponsored by:

Lego Printer Prints Lego

[Gosse Adema] made his very first instructable by detailing his Lego 3D printer build. It’s Prusa i3 based, and originally started out as an A4 plotter with repurposed steppers out of an old HP printer. After upgrading to some NEMA 17 steppers, it became a full-blown 3D printer.

It turns out that NEMA 17 stepper mounting holes align perfectly with Lego, making it super easy to mount them. Check out this Lego ‘datasheet’ for some great details on measurements.

The brains of the printer are occupied by Marlin running atop a Atmega 2560, and Pronterface for the PC software. He tops it off with a Geeeteck built MK8 extruder boasting a 0.3 mm nozzle that accepts 1.75 mm filament.

As with almost any DIY 3D printer build, his first prints didn’t turn out so well. After adjusting the nozzle and filament size in the software, he started to get some good results. Be sure to check out the video below to see this Lego 3D printer in action.

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