A Command-Line Stepper Library with All the Frills

When you already know exactly where and how you’d like your motor to behave, a code-compile-flash-run-debug cycle can work just fine. But if you want to play around with a stepper motor, there’s nothing like a live interface. [BrendaEM]’s RDL is a generic stepper motor driver environment that you can flash into an Arduino. RDL talks to your computer or cell phone over serial, and can command a stepper-driver IC to move the motor in three modes: rotary, divisions of a circle, and linear. (Hence the acronumical name.) Best of all, the entire system is interactive. Have a peek at the video below.

The software has quite a range of capabilities. Typing “?” gets you a list of commands, typing “@” tells you where the motor thinks it is, and “h” moves the motor back to its home position. Rotating by turns, degrees, or to a particular position are simple. It can also read from an analog joystick, which will control the rotation speed forward and backward in real time.

Division mode carves the pie up into a number of slices, and the motor spins to these particular locations. Twelve, or sixty, divisions gives you a clock, for instance. Acceleration and deceleration profiles are built in, but tweakable. You can change microstepping on the fly, and tweak many parameters of the drive, and then save all of the results to EEPROM. If you’re playing around with a new motor, and don’t know how quickly it can accelerate, or what speeds it’s capable of, nothing beats playing around with it interactively.

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Portable RetroPie Suitcase For Multiplayer On The Go!

Portable gaming — and gaming in general —  has come a long way since the days of the original Game Boy. With a mind towards portable multiplayer games, Redditor [dagcon] has assembled a RetroPie inside a suitcase — screen and all!

This portable console has almost everything you could need. Four controllers are nestled beside two speakers. Much of the power cabling is separated and contained by  foam inserts. The screen fits snugly into the lid with a sheet of rubber foam to protect it during transport.

Tucked behind the monitor rests the brains of this suitcase console: a Raspberry Pi and the associated boards. [Dagcon] resorted to using a dedicated sound card for the speakers, diverting the output from the HDMI port. An LCD screen controller was also necessary as the screen had been re-purposed from its previous life as a laptop screen. [Dagcon] offers some tips on how to go about accomplishing this yourself and a helpful Instructables link.

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Heat Pump Gets Brain Transplant; Such is Life in Latvia

If you buy a used heat pump that was made in China and try to use it in Northern Europe, there are bound to be issues. If said heat pump ends up encased in a block of ice that renders it ineffective, you’ve got two choices: give up and buy a proper heater, or hack a new ice-busting brain board into the heat pump and get back to life.

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A little too icy.

[Evalds] chose the latter course, obviously, and in the process he gives us a pretty good look at how heat pumps work and how to overcome their deficiencies. In [Evalds]’ Latvia, winters can be both cold and humid, which can worsen an inherent problem with air-coupled heat pumps: they tend to ice up. As the outside coil is cooled to pick up as much heat as possible from the outside air, water vapor condenses out on the coils and freezes. Most heat pumps account for this by occasionally running in reverse, heating the outdoor coils to clear the ice buildup. [Evalds]’  had nothing more than a simple timer to kick off the defrost cycle, and it wasn’t keeping up with the Latvian winter. An Arduino replaced the OEM controller, and wired up to temperature sensors and an IR sensor that watches for ice buildup on the lower part of the coil, the heat pump is now much better behaved.

Of course it wasn’t as smooth as all that — [Evalds] has some hoops to jump through, including EMI problems and a dodgy Arduino clone. But he stuck with it and brought the heat pump back online, likely at far less expense than HVAC techs would charge for a service call.

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Taking A Robot For A Drive

Instructables user [Roboro] had a Mad Catz Xbox steering wheel controller he hasn’t had much use for of late, so he decided to hack and use it as a controller for a robot instead.

Conceivably, you could use any RC car, but [Roboro] is reusing one he used for a robot sumo competition a few years back. Cracking open the controller revealed a warren of wires that were — surprise, surprise — grouped and labelled, making for a far less painful hacking process. Of course, [Roboro] is only using the Xbox button for power, the player-two LED to show the connection status, the wheel, and the pedals, but knowing which wires are which might come in handy later.

An Arduino Uno in the wheel and a Nano in the robot are connected via CC41-A Bluetooth modules which — despite having less functionality than the HM10 module they’re cloned from — perform admirably. A bit of code and integration of a SN754410 H-bridge motor driver — the Arduino doesn’t supply enough current to [Roboro]’s robot’s motors — and the little robot’s ready for its test drive.

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Your Arm Is The Ideal Controller

With interest and accessibility to both wearable tech and virtual reality approaching an all-time high, three students from Cornell University — [Daryl Sew, Emma Wang, and Zachary Zimmerman] — seek to turn your body into the perfect controller.

That is the end goal, at least. Their prototype consists of three Kionix tri-axis accelerometer, gyroscope and magnetometer sensors (at the hand, elbow, and shoulder) to trace the arm’s movement. Relying on a PC to do most of the computational heavy lifting, a PIC32 in a t-shirt canister — hey, it’s a prototype! — receives data from the three joint positions, transmitting them to said PC via serial, which renders a useable 3D model in a virtual environment. After a brief calibration, the setup tracks the arm movement with only a little drift in readings over a few minutes.

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NES Classic Edition – Controller Mod

The Nintendo Classic Mini took the world by storm this year — finally, an NES in a cute, tiny package that isn’t 3D printed and running off a Raspberry Pi! It’s resoundingly popular and the nostalgic set are loving it. But what do you do when you’re two hours deep into a hardcore Metroid session and you realize you need to reboot and reload. Get off the couch? Never!

[gyromatical] had already bought an Emio Edge gamepad for his NES Mini. A little poking around inside revealed some unused pads on the PCB. Further investigation revealed that one pad can be used to wire up a reset button, and two others can be used to create a home switch. Combine this with the turbo features already present on the Emio Edge, and you’ve got a pretty solid upgrade over the stock NES Mini pad. Oftentimes, there’s extra functionality lurking inside products that manufacturers have left inactive for the sake of saving a few dollars on switches & connectors. It’s always worth taking a look inside.

Now, back in 2006, the coolest hack was running Linux on everything — and somebody’s already trying to get Linux on the NES Mini.

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Touchless MIDI: The Secret’s In the Mitten

MIDI is a great tool for virtually any musician. Unless you’re a keyboard player, though, it might be hard to use it live. [Evan] recently came up with a great solution for all of the wistful guitar players out there who have been dreaming of having a MIDI interface as useful as their pianist brethren, though. He created a touchless MIDI controller that interfaces directly with a guitar.

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