Wait, THAT’S an Electric Guitar?

Mechatronic Guitar

What you’re looking at above is a six-stringed mechatronic slide guitar, where each string and associated servos is assigned its own MIDI channel.

It’s a project [Jim Murphy] has been working on for a while now, and technically, it’s the second iteration — he’s calling it the Swivel 2. The original Swivel was more of a proof of concept, using bulky stepper motors and solenoids — in this one he’s upgraded to hobby style servos, using four per string. One to change the pitch, one to clamp the pitch shifter, and two to pick and dampen the strings.

He’s designed the PCB control boards himself utilizing an Arduino bootloader-equipped ATMEGA328, which takes in the MIDI signal from a computer and moves the servos accordingly — to produce the audio signals he’s been using Ableton Live to write the patterns.

The entire setup was designed in 3D CAD and is designed to be completely modular. He’s even made the guitar pickups himself using 3D printed spools, and hand wrapping the coils with copper enamel wire. Lend an ear after the break to hear it in action.

[Read more...]

Build a Bass Master 3000 Carnival Game

Bass Master 3000

We’ve all been there. You are having fun walking around the carnival when you suddenly find yourself walking past the carnival games. The people working the booths are taunting you, trying to get you to play their games. You know the truth, though. Those games are rigged. You don’t know how they do it. You just know that they do… somehow.

Now you can put your worries to rest and build your own carnival game! [John] built his own “Bass Master 3000” style carnival game and posted an Instructable so you can make one too.

The game is pretty straightforward. You have a giant fish-shaped target with a wide open mouth. You take hold of a small fishing reel with a rubber ball on the end. Your goal is to cast the ball out and hit the fish in its big mouth. If you hit the mouth, you get to hear a loud buzzer and see some flashing lights. The system also uses a webcam to take a candid photo of the winner. A computer screen shows all of the winners of the day.

The brain of the system is an Arduino Yún. The Yún is similar to an Uno but it also has some extra features. Some good examples are an Ethernet port, a wireless adapter, and an SD card slot. The mouth sensors are just two piezo elements. Each sensor is hooked up to the Arduino through a small trim pot. This allows you to dial in the sensitivity of each sensor. The lights and the buzzer are controlled via a relay, triggered by a 5V digital pin on the Arduino.

The Yún actually has a small on-board Linux computer that you can communicate with from inside the Arduino environment. This allows [John] to use the Yún to actually take photos directly from a web cam, store them on the local SD card, and display them on a local web server. The web server runs a simple script that displays a slide show of all of the photos stored on the card.

The final piece of the game is the physical target itself. The target is painted using acrylic paint onto a small tarp. The tarp is then attached to a square frame made from PVC pipe. The mouth of the fish is cut out of the tarp. A large piece of felt is then placed behind the hole with the piezo sensors attached. A short length of copper pipe helps to weigh down the bottom of the felt and keep it in place. The important thing is to make sure the felt isn’t touching the tarp. If it touches, it might be overly sensitive and trigger even when a player misses.

Now you know how to build your own Bass Master 3000 carnival game. Whether you rig the game or not is up to you. Also, be sure to check out a video of the system working below. [Read more...]

Making a Nitinol Wire Inchworm

nitinol_wire_inchworm_shape_memory_alloy_anim

[Steven's] at it again with another cool science experiment that isn’t too difficult to do. This time he’s made himself a Nitinol wire inchworm, which actually moves across the table when you apply a switching electrical current to it!

Nitinol is a shape memory alloy which has a cool property that causes it to retain (and return to) a preset shape when heat (or electricity!) is applied. It’s actually quite simple — he’s wrapped the Nitinol wire tightly around a nail, and then heated it to set it to a coiled shape. Now the Nitinol spring can be stretched out flat, but as soon as it is heated, it will attempt to return to its coiled state!

Using some balsa wood and a few other odds and ends he’s taken advantage of this memory effect to make an electric inchworm — check it out after the break!

[Read more...]

Apple Forces Non-Mac User To Make Ergonomic Mac Keyboard

Mac Ergonomic Keyboard

If you’ve ever typed for a significant amount of time you know that it can become painful. Long term exposure can cause wrist and arm injuries. There are some things that can help alleviate the risk of injury like taking frequent breaks, good posture and using an ergonomic keyboard. [Ian] likes the feel of Mac keyboard keys but doesn’t like the traditional straight layout. Unfortunately, Apple doesn’t make an ergonomic keyboard so [Ian] stepped up to the plate and made one for himself.

Mac Ergonomic Keyboard

Just starting this project was an extreme pain. Apple glues their Mac keyboards together. A heat gun was used to melt the glue to 400°F as kitchen utensils were stuck in between the halves of the case, keeping the glue from re-sealing the case together. Once the case was apart the unnecessary keys were removed. [Ian] is actually modifying two keyboards into one because he wants the middle keys to show up on both sides of the keyboard. With the necessary keys identified, the metal support frame was removed from the unneeded sides of the keyboard.

[Read more...]

An Online Course For FPGA And CPLD Development

FPGA

Over on the University of Reddit there’s a course for learning all about FPGAs and CPLDs. It’s just an introduction to digital logic, but with a teacher capable of building a CPLD motor control board and a video card out of logic chips, you’re bound to learn something.

The development board being used for this online course is an Altera EMP3032 CPLD conveniently included in the Introduction to FPGA and CPLD kit used in this course. It’s not a powerful device by any measure; it only has 32 macrocells and about 600 usable gates. You won’t be designing CPUs with this thing, but you will be able to grasp the concept of designing logic with code.

Future lessons include building binary counters, PWM-controlled LEDs, and a handheld LED POV device. In any event, it’s a great way to learn about how programmable logic actually works, and a fairly cheap way to get into the world of FPGAs and CPLDs. Introductory video below.

[Read more...]

LinuxCNC Based Plasma Cutter Router

cnc plasma cutter

If a wood CNC router just isn’t enough for you, you’re going to need something a little bit more powerful. Relatively speaking, the next most affordable step up is a CNC plasma cutter. Mhmm… Plasma…

maker-works

[Maker Works] of Ann Arbor decided it was time to add some serious metal working capabilities to their already impressive mech shop. The design is based on of  [JoesCNC], however they’ve opted for some seriously beefy servo motors, instead of steppers.

The frame is made out of 8020 aluminum extrusions, which certainly adds to the cost, but results in a very professionally built machine. X and Y axis’ make use of NEMA 34 Servo motors, driven by Granite Devices VSD-E servo drivers. The Z-axis uses a NEMA 23 with a Gecko 320X driver. To further increase the power of these guys, 10:1 reduction gearboxes are used on both the X and Y.

All in all the project cost approximately $8,000, though after lessons learned, they think they could redo it for around $6,000.

When they first started testing it, they were dismayed with how dirty the room got from the fine dust created by the plasma cutter — so they’ve upgraded to a water tray bed (2″ deep), which helps immensely. In fact, the part doesn’t even need to be fully submerged in water for it to cut down pretty much all of the dust. The water also helps prevent damage to the aluminum bed underneath.

[Read more...]

How To Laser Cut Mylar Solder Stencils

Solder Stencil

When you think about the difficulties of working with surface mount components, the first thing that often comes to mind is trying to solder those tiny little parts. Instead of soldering those parts by hand, you can actually apply solder paste to the pads and place all of the components on at once. You can then heat up the entire board so all of the parts are soldered simultaneously. It sounds so much easier! The only problem is you then need a solder stencil. You somehow have to get a thin sheet of material that has a perfectly sized hole where all of your solder pads are. It’s not exactly trivial to cut them out by hand.

[Juan] recently learned a new trick to make cutting solder stencils a less painful process. He uses a laser cutter to cut Mylar sheets into stencils. [Juan] appears to be using EagleCAD and Express PCB. Both tools are available for free to hobbyists. The first step in the process is to export the top and bottom cream layers from your CAD software.

The next step is to shrink the size of the solder pads just a little bit. This is to compensate for the inevitable melting that will be caused by the heat from the laser. Without this step, the pads will likely end up a little bit too big. If your CAD software exports the files as gerbers, [Juan] explains how to re-size the pads using ViewMate. If they are exported as DXF files, he explains how to scale them using AutoCAD. The re-sized file is then exported as a PDF.

[Juan's] trick is to actually cut two pieces of 7mil Mylar at the same time. The laser must be calibrated to cut all the way through the top sheet, but only part way into the bottom piece. The laser ends up slightly melting the edges of the little cut out squares. These then get stuck to the bottom Mylar sheet. When you are all done cutting, you can simply pull the sheets apart and end up with one perfect solder stencil and one scrap piece. [Juan] used a Full Spectrum 120W laser cutter at Dallas Makerspace. If you happen to have this same machine, he actually included all of the laser settings on his site.