Two Turntables and No Microphone

It used to be that you had to spend real money to get an alternative controller for your electronic musical arsenal. These days, with cheap microcontrollers and easily-accessible free software libraries, you can do something awesome for pocket change. But that doesn’t mean that you can’t make a sexy, functional piece of art along the way! [Jan Godde] did just that with his cleverly named Wooden Sensor Box With Two Rotary Disks. (If you’ve got a better name for this thing, toss it in the comments.)

mpv-shot0003From what we can see, the box has two potentiometer sliders, two touch-sensitive potentiometers, two force sensitive resistors, a slew of knobs, and a whole bunch of (capacitive?) touch points. In short, a ton of continuous controllers of all sizes and shapes in an aesthetic case. But stealing the show, and giving the device its name, are two platters from old hard drives that serve as jog wheels.

As shown in the video below the break, the two jog wheels are covered with alternating stripes on the underside. Each platter has a dedicated pair of IR LEDs and photodetectors underneath serving as a quadrature encoder that allows [Jan] to tell which direction the platters are rotating, and how far.

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Palm Interface Has You Suggest where Self Driving Car Should Go

These days, our automobiles sport glittering consoles adorned with dials and digits to keep us up-to-date with our car’s vitals. In the future, though, perhaps we just wont need such vast amounts of information at our fingertips if our cars are driving themselves around. No information? How will we tell the car what to do? On that end, [Felix] has us covered with Stewart, a tactile gesture-input interface for the modern, self driving car.

Stewart is a 6-DOF “Stewart Interface” capable of both gesture input and haptic-output. Gesture input enables the car’s passenger to deliver driving suggestions to the car. The gentle twist of a wrist can signal an upcoming turn at the next intersection; pulling back on Stewart’s head “joystick style” signals a “whoa–slow down, there, bub!” Haptic output via 6 servos pushes around Stewart’s head in the car’s intended direction.  If the passenger agrees with the car, she can let Stewart gesture itself in the desired direction; if she disagrees; she can veto the car’s choices by moving her hand directly against Stewart’s current output gesture. Overall, the interface unites the intentions of the car and the intentions of the passenger with a haptic device that makes the connection feel seamless!

We know we’re not supposed to comment on the “how” with art projects–but we’re engineers–and this one makes us giddy with delight. We’re imagining those rc car shock absorbers dramatically dampening the jittery servos and giving the user a nice resistive feel. Interconnects are laser cut acrylic, and the shell is a smoothly contoured 3d print. We’ve seen Stewart Interfaces before, but nothing with the look-and-feel of a sleek design feature on its way to being dropped into the cockpit of our future self-driving cars.

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Broken Finger Is No Obstacle to Modern Hacker

[Jim Merullo] and his son were enjoying a nice game of Frisbee when an unfortunate dive led to an injury. His son broke his pinky finger leaving doctors no choice other than bounding his entire left hand in an unreasonably large cast. For most, this would mean no use of the left hand for several weeks, which is somewhat problematic if tin01your son has a Minecraft addiction.  [Jim], however, is no stranger to the hacker community and began working on a solution. He broke out the #2 Philips screwdriver, fired up the soldering iron and got to work.

A detailed analysis of the injured left hand revealed limited use of the middle and ring finger, and full use of the thumb. Because his son played the game using his right hand for the mouse and left for the keyboard, he needed to find a way for him to operate a keyboard with the limited use of his left hand. He took apart an old USB keyboard and soldered up some tactile switches to emulate the needed key presses. After making a fashionable Altoids tin mount that fit over the cast, his son was able to enjoy his favorite video game with limited interruption.

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Disk Hack Creates Persistence of Vision

[Adam Antok] was compelled to create this repurposed hard drive persistence of vision hack after seeing a toy of the same nature.

hdd-display-schematicHe used the frame, disk and motor from a drive and added LEDs under the spinning disk as the light source. The disk has 8 small holes drilled equidistant around the disk, and spiraling slightly toward the center. As the holes pass by the LEDS they are flashed by the ATtiny2313 processor to create images. To determine the position of the platters a Hall effect sensor is monitored by the 2313 to detect a magnet on the underside of the disk. There is room to display ten characters at one time. Each cursor position can scroll through the character set by rotating an encoder. For all the precision needed to coordinate the LEDs with the spinning holes the electronics and software code are amazingly simple. That’s a really nice job, [Adam]!

Persistence of vision hacks are to hackers like flames are to moths. One really nice thing about [Adam’s] project is that you can interact with it while it’s running. Check it out after the break.

For a novel take on POV, check out this slow swinging pendulum clock.

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Bootstrapping Motion Input with Cheap Components

Motion control is a Holy Grail of input technology. Who doesn’t want an interface that they can control with simple and natural movements? But making this feel intuitive to the user, and making it work robustly are huge hills to climb. Leap Motion has done an excellent job creating just such a sensor, but what about bootstrapping your own? It’s a fun hack, and it will give you much greater appreciation for the currently available hardware.

Let’s get one thing straight: This device isn’t going to perform like a Leap controller. Sure the idea is the same. Wave your hands and control your PC. However, the Leap is a pretty sophisticated device and we are going to use a SONAR (or is it really SODAR?) device that costs a couple of bucks. On the plus side, it is very customizable, requires absolutely no software on the computer side, and is a good example of using SONAR and sending keyboard commands from an Arduino Leonardo to a PC. Along the way, I had to deal with the low quality of the sensor data and figure out how to extend the Arduino to send keys it doesn’t know about by default.

The Plan

The plan is to take an inexpensive SONAR module (the HC-SR04) and an Arduino Leonardo and use it to perform some simple tasks by mimicking keyboard input from the user. The Leonardo is a key element because it is one of the Arduinos that can impersonate a USB keyboard (or mouse) easily. The Due, Zero, and Micro can also do the trick using the Arduino library.

I wanted to determine how many gestures I could really determine from the HC-SR04 and then do different things depending on the gesture. My first attempt was just to have the Arduino detect a few fingers or a hand over the sensor and adjust the volume based on moving your hand up or down. What I didn’t know is that the default Arduino library doesn’t send multimedia keys! More on that later.

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Foam and Antistatic bag Bring Vintage Compaq Keyboard back to life

After winning an online auction for an 1980s vintage Compaq Portable PC, [leadacid44] discovered why it only cost him $5USD – the keyboard was shot. Not willing to accept having forked out $45USD to ship a brick, he tore into the ancient machine and came up with a found-material solution to the wonky keyboard.

[leadacid44]’s very detailed writeup of the fix for his Compaq includes a thorough examination of the guts of the machine. He got it to boot to MS-DOS 5.0 off of a 20MB ISA hard drive card and began probing the keyboard problem. It turns out the Compaq keyboard has much in common with a modern touchscreen, in that it’s a capacitive keyboard. Unfortunately the foam disks used as springs under each key cap had degraded over the last 30 years, so [leadacid44] began a quest to replace them. After much experimentation and a few false starts, he created a sandwich of transparency film, closed-cell polyethylene foam, and a Mylar antistatic bag. Many discs were punched out with a leather punch and tediously placed in the body of each key switch, and the quick brown fox was soon jumping flawlessly over the lazy dog.

We’ve seen some fixes to these lovable luggables before, like this dumpster queen that became a Hackaday Retro submission. At least [leadacid44]s machine didn’t release the Magic Blue Smoke like that one did.

Quick Keyboard Hack to Control Heavy Loads

When you want to control an external device (like a lamp) from your computer, you might reach for a USB enabled micro. Looking for an inexpensive and quick option to control two lamps [Pete] wanted to control a couple 12 volt halogen lamps, he reached for his keyboard and used a little bit of python.

Desktop PC keyboards have 3 LED’s indicating lock functions, hardly anyone uses the scroll lock, and on a laptop with no keypad, numlock is no big loss as well. Adding wires to the little PCB out of a USB keyboard the numlock and scroll lock LED’s 5 volt output was redirected to a switching circuit.

That switching circuit takes the output of either LED, inverts it with a PNP transistor, then connects to the gate of a FQP30N06L, “logic level” mosfet transistor to handle the heavy lifting. Once the wiring is in place a fairly simple Python script can take over turning on and off the two chosen lock keys, giving  control of up to 32 amps with the touch of a button.