Unix On Your Breadboard

As smartphones continue to get bigger and bigger, the race to have the smallest chip running Unix (or Linux, as the case may be) is still on. A new contender in this arena is [Serge] who has crammed RetroBSD on a Fubarino microcontroller for a powerful breadboard-friendly device.

The device uses a PIC32MX795 processor to run version 2.11BSD Unix for microcontrollers. It uses only 128 kbytes of RAM which is great for the limited space available, but it doesn’t skimp on software. It has a C compiler, assembler, and a whole host of other utilities that you’d expect to find in something much more powerful. All of this comes in a package that has breadboard-compatible pins so you can interface your Unix with the real world.

There’s a video below that shows the device in action, and a whole host of instructions that’ll get you up and running in no time if you have the hardware available. [Serge] mentioned that this would run on other architectures but is looking for others to join the project to port it to those processors. This isn’t the first time we’ve seen *nix installed on a microcontroller, but it is one of the more useful ones!

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Hackaday Prize Entry: Density Altitude Gauge

Despite what extraordinarily overpowered quadcopters suggest, the air pressure of whatever a flying machine flys at is extremely important. Pressure is dependent on altitude and temperature, and there are hundreds of NTSB investigations that have concluded density altitude – pressure altitude corrected for nonstandard temperature variations – was the reason for a crash. Normally density altitude is computed through a slide rule or a flight computer, with the pilot entering in altitude and temperature, but somehow accidents still happen. For his entry to The Hackaday Prize, [Neil McNeight] is building an automated density altitude calculator to automate the process entirely.

Instead of having a pilot enter the altitude and temperature into a flight computer manually, [Neil]’s device grabs the current altitude from a GPS unit, and reads the temperature with a tiny sensor acquired from SparkFun. With just a little bit of math, this device will spit out the altitude an airplane or ‘copter thinks it’s at.

While the FAA won’t allow instruments that are cobbled together on a breadboard, this does have a few applications in the RC world. There are extremely high performance racing quadcopters out there now, and knowing how the craft will perform before flying it will save a few props.


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Hackaday Prize Entry: Open Source Hydroponic Monitoring System

A few months ago, [Adam] was building a controller system for a small hydroponic system he had set up in his basement. Since then, the Hackaday Prize was announced, and given the theme – saving the world one plant at a time – he’s renvisioning his garden control and monitoring system as a Hackaday Prize entry.

While the mechanical and green part of the build is exactly what you would expect from something designed from hardware store parts, the electronics are rather interesting. All the plants in either a hydroponic or dirt-based setup will have their moisture level and PH monitored by a a set of electronics that push data up to the cloud.

The current hardware setup includes a DyIO, a very cool dev platform with 24 digital I/Os and 24 servo outputs, a Raspberry Pi, and a few module boards loaded up with ARM microcontrollers and an ESP8266. [Adam] is hitting all the hardware on this build.

So far, [Adam] has a few boards sent out to a board fab, including an analog sensor module, a digital sensor module. a WiFi module hub, and a few bits and bobs that make integration into an existing garden or hydroponic setup easier. It’s a great project for this year’s Hackaday Prize, and proof that you don’t need to come up with a new build to submit something.


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Hackaday Prize Entry: Multispectral Imaging For A UAV

At least part of the modern agricultural revolution that is now keeping a few billion people from starving to death can be attributed to remote sensing of fields and crops. Images from Landsat and other earth imaging satellites have been used by farmers and anyone interested in agriculture policy for forty years now, and these strange, false-color pictures are an invaluable resource for keeping the world’s population fed.

The temporal resolution of these satellites is poor, however; it may be a few weeks before an area can be imaged a second time. For some uses, that might be enough.

For his Hackaday Prize entry (and his university thesis), [David] is working on attaching the same kinds of multispectral imaging payloads found on Earth sensing satellites to a UAV. Putting a remote control plane up in the air is vastly cheaper than launching a satellite, and being able to download pictures from a thumb drive is much quicker than a downlink to an Earth station.

Right now, [David] is working with a Raspberry Pi and a camera module, but this is just experimental hardware. The real challenge is in the code, and for that, he’s simulating multispectral imaging using Minecraft. Yes, it’s just a simulation, but an extremely clever use of a video game to simulate flying over a terrain. You can see a video of that separated into red, green, and blue channels below.


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Hackaday Prize Entry: DC Motor Controller

There are a lot of cheap Chinese CNC machines out there with okay mechanics and terrible electronics. The bearings aren’t complete crap, but the spindle of these CNC machines is a standalone PWM controller with a pot to control the speed. This means you can’t control the spindle speed with LinuxCNC or Mach3.

For his Hackaday Prize entry, [SUF] is building a DC motor controller for a Chinese spindle motor that doesn’t use any kind of encoder. The first part of that project is fairly easy; [SUF] has already built a high current driver. The second bit is a little it harder – because these spindles don’t have an encoder, [SUF] will have to read voltage spikes on the motor poles, giving him the RPM of the spindle. From there, it’s a bit of PID code to get this spindle running at a desired RPM and connecting it to a CNC control box.

So far, [SUF] has a second version of his board waiting for assembly. In the first version of the board, the switching time for the MOSFET was a little slow, but that’s all corrected in the current revision. It’s a great project to extend the capability of these cheap CNC machines, and perfect project for the Hackaday Prize.


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Hackaday Prize Entry: A $100 CT Scanner

What do you do when you’re dad’s a veterinarian, dumped an old x-ray machine in your garage, and you’re looking for an entry for The Hackaday Prize? Build a CT scanner, of course. At least that’s [movax]’s story.

[movax]’s dad included a few other goodies with the x-ray machine in the garage. There were film cassettes that included scintillators. By pointing a camera at these x-ray to visible light converting sheets, [movax] can take digital pictures with x-rays. From there, it’s just building a device to spin around an object and a lot – a lot – of math.

Interestinly, this is not the first time a DIY CT scanner has graced the pages of Hackaday. [Peter Jansen] built a machine from a radiation check source, a CMOS image sensor, and a beautiful arrangement of laser cut plywood. This did not use a proper x-ray tube; instead, [Peter] was using the strongest legally available check source (barium 133). The scan time for vegetables and fruit was still measured in days or hours, and he moved on to build an MRI machine.

With a real source of x-rays, [movax]’s machine will do much better than anything the barium-based build could muster, and with the right code and image analysis, this could be used as a real, useful CT scanner.


The 2015 Hackaday Prize is sponsored by:

Hackaday Prize Entry: A 7805 Replacement

The 7805 voltage regulator is a great device if you want a simple way of bringing a voltage down to 5V. It’s a three-pin, one-component solution that puts out five volts and a lot of heat. Simple, not efficient. For his Hackaday Prize entry, [K.C. Lee] is working on a much more efficient drop-in replacement for the 7805.

Linear regulators like the 7805 are great, but they’re not terribly efficient. Depending on the input voltage you might see 50% efficiency. Going to a switch mode supply, that efficiency shoot up to about 90%.

For his drop-in replacement, [K.C. Lee] is using the LM3485, a switch mode regulator that only needs a few extra parts to turn it into a replacement for the 7805. You will need a cap on the input, but you should already be putting those in your circuit anyway, right?


The 2015 Hackaday Prize is sponsored by: