$250; Pushing The Limit On Cheap (And Functional) CNC Machine Builds

June 28, 2014 by 59 Comments

 

$250 cnc machine - rotary tool

Cost is always a drawback and a hurdle when buying or building a CNC Machine, especially when building it just for fun or hobby. [Eric] was able to cobble together a working 3-axis rotary tool based machine for about $250, a few trips to the hardware store and a bunch of time.

The machine design is loosely based on this one he found on Instructables. [Eric] chose this style because he felt the boom supported tool would have been more stable and easier to build than a gantry style machine. Skate bearings, HDPE sliders and c-channel aluminum were used to support the XY table instead of traditional linear bearings and rails. All three axes are driven with stepper motors and 1/4″-20 threaded rods. The Harbor Freight dremel-style rotary tool helps keep the overall cost down.

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Rubik’s Cube Solver Made Out Of Popsicle Sticks And An Arduino

June 28, 2014 by 15 Comments

rubix cube solver

[Matt] recently learned both how to solve a Rubik’s cube and the basics of an Arduino. Putting the two together, he decided to try his hand at making an automatic Rubik’s Cube solver!

We’ve seen this done quite a few times using LEGO Mindstorms, but we’re much more impressed with [Matt’s] clever use of popsicle sticks and mechanical linkages…. The device uses just two servos. One to rotate the base, and the second to flip the cube over.

He’s using an Arduino UNO (R3) with 2 Hitec HS-311 hobby servos, some popsicle sticks, hot glue, a paper towel roll, and a bit of plywood. He wrote the code to solve the cube himself, and has shared it on GitHub — but he didn’t stop there and decided to create a GUI to go with it using Python.

It’s not that fast, but it’ll solve a cube in about 20 minutes — stick around after the break to see it in action!

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Wait, THAT’S An Electric Guitar?

June 28, 2014 by 36 Comments

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.

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Build A Bass Master 3000 Carnival Game

June 28, 2014 by 3 Comments

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. Continue reading “Build A Bass Master 3000 Carnival Game” →

Making A Nitinol Wire Inchworm

June 28, 2014 by 7 Comments

[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!

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Apple Forces Non-Mac User To Make Ergonomic Mac Keyboard

June 27, 2014 by 64 Comments

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.

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An Online Course For FPGA And CPLD Development

June 27, 2014 by 16 Comments

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.

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