Orka Controls the (Pi) World

If you deploy a lot of Raspberry Pi computers, you might find it inconvenient to log into each one to perform different tasks. Orka, an open source project by [Karthik K], is a server that runs on a desktop PC (Windows, Linux, or Mac) and can control multiple Orka clients (that can run on a Pi, or a desktop PC). We understand that [Karthik K] is looking for Mac testers, by the way.

From the server, you can execute commands and create tasks. You can also receive notification when a client PC reaches a threshold (for example, over temperature or too much CPU or RAM usage). You can open a shell on a client and do other operations.

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Open Design Oscilloscope Could be (Almost) Free

If you could only own one piece of test equipment, it should probably be an oscilloscope. Then again, modern scopes often have multiple functions, so maybe that’s not a fair assertion. A case in point is the Scopefun open hardware project. The device is a capable 2-channel scope, a logic analyzer and also a waveform and pattern generator. The control GUI can work with Windows, Linux, or the Mac (see the video, below).

The hardware uses a Xilinx Spartan-6 FPGA. A GUI uses a Cypress’s EZ-USB FX2LP chip to send configuration data to the FPGA.  Both oscilloscope channels are protected for overvoltage up to +/- 50 V. The FPGA samples at 100 Mhz through a 10-bit dual analog-to-digital converter ( ADC ). The FPGA handles triggering and buffers the input before sending the data to the host computer via the USB chip. Each channel has a 10,000 sample buffer.

There are also two generator outputs with short circuit and overvoltage protection ( +/- 50 V ). Generator channels have 50 Ohm internal impedance and also operates via the GUI using the same USB chip. The FPGA generates signals at 50 Mhz using counters, algorithms, or simple waveform data and feeds a DAC.

A 16-bit digital interface can be set as inputs or outputs. The FPGA samples inputs at 100 MHz. The output voltage can be set, but inputs are 5 V tolerant.

According to the developer, you can build the scope from the information provided by using free sample chips from the various vendors, only paying for the small components and the cost of the PCB.

We’ve looked at several low-cost scope options before. Labtool even boasts some similar features.

The Hackaday Prize: An Open Electric Wheelchair

[Irene Sans] and [Alvaro Ferrán Cifuentes] feel that electric wheelchairs are still too expensive. On top of that, as each person’s needs are a little different, usually don’t exactly fit the problems a wheelchair user might face. To this end they’ve begun the process of creating an open wheelchair design which they’ve appropriately dubbed OpenChair.

As has been shown in the Hackaday Prize before, there’s a lot of things left to be desired in the assistive space. Things are generally expensive. This would be fine, but often insurance doesn’t cover it or it’s out of the range of those in developing nations.  As always, the best way to finish is to start, so that’s just what [Irene] and [Alvaro] has done.

They based their initial design on the folding wheel chair we all know. It’s robust enough for daily use and is fairly standard around the world. They designed a set of accessories to make the wheelchair more livable for daily use as well as incorporating the controls.

The next problem was locomotion. Finding an off-the-shelf motor that was powerful enough without breaking the budget was proving  difficult, but they had an epiphany. Why not use mass production toy crap to their advantage. The “hoverboards” that were all the rage this past commerical holiday season were able to roll a person around, so naturally a wheelchair would be within the power range.

They extracted the two 350 watt hub motors, batteries, and control boards. It took a bit of reverse engineering but they were able to get the hub drive motors of the hoverboard integrated with the controls on their wheelchair.

In the end they were able to cut the price of a regular electric wheelchair in half with their first iteration and set the foundation for future work on an open electric wheelchair system. Certainly more work could bring even better improvements.

3D-Printed Prosthetic Puts the Power in the Hands of Those Who Need It

In recent years, prosthetics have seen a dramatic increase in innovation due to the rise of 3D printing. [Nicholas Huchet] — missing a hand due to a workplace accident in 2002 — spent his residency at Fab Lab Berlin designing, building, testing and sharing the files and tutorials for a prosthetic hand that costs around 700 Euros.

[Huchet] founded Bionicohand with the intent of using the technology to make prosthetic limbs available to those without reliable medical or social assistance — as well as for amputees in countries without such systems — which can cost tens of thousands of dollars. The parts took a week to print while assembly and modifications to suit [Huchet’s] arm took another four days, but the final product is functional and uses affordable myoelectric sensors, boards and servos — plus there’s always the option of using a basic 3D scanner to accommodate for existing prosthetic mounts for the individual.

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Shell Game

A lot of us spend a lot of time switching between Windows and Linux. Now that platforms like the Raspberry Pi are popular, that number is probably increasing every day. While I run Linux on nearly everything I own (with the exception of a laptop), my work computers mostly run Windows. The laptop is on Windows, too, because I got tired of trying to get all the fancy rotation sensors and pen features working properly under Linux.

What I hate most about Windows is how hard is it to see what’s going on under the hood. My HP laptop works with a cheap Dell active stylus. Sort of. It is great except around the screen edges where it goes wild. Calibration never works. On Linux, I could drill down to the lowest levels of the OS if I were so inclined. With Windows, it is just tough.

War is Shell

One place where Linux always used to have an advantage over DOS and Windows was the shell. There are lots of variations available under Linux, but bash seems to be the current pick for most people. If you want more power, you can move to some alternatives, but even bash is pretty powerful if you learn how to use it and have the right external programs (if you don’t believe it, check out this web server).

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Open Source SNES to USB Converter Lets You Emulate Legally

[Andrew Milkovich] was inspired build his own Super Nintendo cartridge reader based on a device we covered an eternity (in internet years) ago. The device mounts a real cartridge as a USB mass storage device, allowing you to play your games using an emulator directly from the cart.

This uses a Teensy++ 2.0  at its core. [Andrew] had to desolder the EEPROM pins from the SNES cartridge and reverse engineer the pinouts himself, but the end result was a device that could successfully read the cartridge without erasing it, no small accomplishment. The finished cartridge reader is build on some protoboard and we’d like to complement [Andrew] on his jumper routing on the underside of that board.

Of course, the experience of any console is just not the same without the original controller. So [Andrew] went a step further and made his own SNES controller to USB converter. This had the venerable Atmel ATmega328 at its core, and can be used separate from the cartridge reader if desired.

Add Robotic Farming to Your Backyard with Farmbot Genesis

Growing your own food is a fun hobby and generally as rewarding as people say it is. However, it does have its quirks and it definitely equires quite the time input. That’s why it was so satisfying to watch Farmbot push a weed underground. Take that!

Farmbot is a project that has been going on for a few years now, it was a semifinalist in the Hackaday Prize 2014, and that development time shows in the project documented on their website. The robot can plant, water, analyze, and weed a garden filled with arbitrarily chosen plant life. It’s low power and low maintenance. On top of that, every single bit is documented on their website. It’s really well done and thorough. They are gearing up to sell kits, but if you want it now; just do it yourself.

The bot itself is exactly what you’d expect if you were to pick out the cheapest most accessible way to build a robot: aluminum extrusions, plate metal, and 3D printer parts make up the frame. The brain is a Raspberry Pi hooked to its regular companion, an Arduino. On top of all this is a fairly comprehensive software stack.

The user can lay out the garden graphically. They can get as macro or micro as they’d like about the routines the robot uses. The robot will happily come to life in intervals and manage a garden. They hope that by selling kits they’ll interest a whole slew of hackers who can contribute back to the problem of small scale robotic farming.