Accurate-ish Pneumatic Cylinder Positioning

pneumatic flow positioning

Pneumatic cylinder positioning? If you have a technical background you should be scratching your head right now. Pneumatic cylinder positioning? That’s not really suppose to work! Well, [arduinoversusevil] has hacked together a system, that… kind of does work.

First a little background on [arduinoversusevil]. He’s building a hydraulic/pneumatic, bartending robot. Awesome.

Anyway, he recently picked up old hydraulic cylinder for next to nothing, and decided to try messing around with it. He purged the oil out of it and is now using it as a pneumatic cylinder. He also picked up a cheap $10 plastic Adafruit flow meter, and decided to try to make a positional pneumatic cylinder. Using a Launchpad development board, he controls the solenoid valves using a Dangerous Prototypes ATX breakout board. Surprisingly the cheap Adafruit flow meter was sufficiently accurate enough to measure the amount of air in the cylinder, which, depending on the load, can be used to position the cylinder, somewhat accurately.

He ran a test of about 360 cycles before the flow meter broke, and was able to achieve an accuracy of about 5mm! Not bad at all. Stick around after the break to see it in action — and to hear his colorful commentary.

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The Apple IIe Becomes a Lisp Machine


Way back in the late 1970s and early 1980s, a few very awesome people around MIT were working on Lisp machines. These computers were designed specifically to run Lisp as their main programming language. Around the same time, a few [Steves] in California were working on the Apple II, which would soon become one of the most popular computers of all time. The Apple II ran BASIC as its main programming language, fine for the time, but surely not as elegant as Lisp. It took more than 30 years, but [Alex] and [Martin] figured out a way to turn the lowly Apple IIe into a Lisp machine.

Developing Lisp for the Apple IIe was surprisingly easy for these guys – they simply wrote a Lisp interpreter in C and used a 6502 compiler to generate some machine code. The main problem of porting Lisp to an Apple II was simply getting the code onto the Apple. We’re assuming this would have been easier had the same project been attempted in the 80s.

To get their interpreter onto the Apple, they used the very awesome ADTPro library that allows data to be loaded onto an Apple II via the cassette port and a modern computer’s microphone and speaker jack. After a solid minute of loading analog data onto this digital dinosaur, [Alex] and [Martin] had a Lisp interpreter running on ancient yet elegant hardware.

The source for the 6502 Lisp interpreter can be found on the GitHub along with all the necessary tools to load it via a modern computer. That’ll give you all the ancient lambdas and parens you could ever want. One warning, though: backspace doesn’t exactly work, so be prepared for a lot of frustration.

You can check out the demo video below.

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Hackaday Links: October 20, 2013


Winter is coming. We’ve see those gloves in stores made specifically to work with your smartphone. [hardsoftlucid] isn’t buying it. He made his own version using… well, you just have to see it.

Here’s an eBookmark for a real book. What? Well, you know how an eReader does a great job of keeping your place between reading sessions? This is an electronic bookmark for paper books which uses LEDs to show you where you last left off reading. [via Adafruit]

[Thomas Brittain] wrote in to share his BLE Module and Pulse sensor updates. Both were featured in a recent Fail of the Week column and the latest iteration takes them from fail to functioning!

You may be able to get a free XMOS xCORE starter kit. The company is giving away 2500 of them. [Thanks Tony]

After learning about custom labels for microcontroller pinouts from [John Meachum] we’re happy to get one more helpful tip: a breadboard trench is a great place to hide axial decoupling capacitors.

A bit of cutting, solder, and configuring lets you turn a simple gamepad into a 4-controller interface for MAME.

Many of the Hackaday Staff are into Minecraft (between Let’s Play videos, running servers, and building computers in-game it’s a wonder we get anything done around here). We restrained ourselves by not making this video of a Restone circuit Blender animation on your desktop into a full front page feature. [via Reddit]


Polyphonic Arduino Sketches


Creating music for the Arduino is simple – just use the tone() library – but it truthfully doesn’t sound that great. That’s because this library is monophonic, making chords difficult or at the very least sound a little weird. [Connor]’s miduino aims to change that, turning raw MIDI files into polyphonic Arduino sketches.

To convert MIDI files into Arduino sketches, [Connor] whipped up a Python script based on midiCSV that reads the notes and channels of a MIDI file and converts it into the language of the Arduino. Unlike the built-in tone() library, miduino is polyphonic making the music produced from any Arduino sound great. It’s basically the difference between writing music for a PC speaker and a true keyboard; sure, you’re only getting square waves, but it sounds much better.

Oddly, [Connor] hasn’t put up his Python script as far as we can tell. All the MIDI songs are being converted on [Connor]’s own Raspberry Pi. This is supposed to be cheaper than a VPS, and makes for a very cool project to boot.

Edit: Miduino isn’t polyphonic yet, but [Connor] says he should have that wrapped up in a week or two.

3Doodler in the Wild

Remember the Kickstarter for the 3Doodler? Well they have just started shipping, and a hackerspace called Open Garage in Belgium just got theirs! Like any good hackerspace after playing with it they took it apart and posted pictures.

This is great because in our original coverage on the 3Doodler, we wondered what it looked on the inside, and whether it could be adapted to use with a CNC machine to make a giant 3D printer. Garage Lab delivered on both.

Stick around after the break to see the innards, and the first test print using a CNC mill!

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Hackerspacing in Europe: The Garage Lab in Düsseldorf


The Garage Lab (translated) is a small hackerspace quite close to the Chaosdorf. As the name implies, it exists in a garage complex — each unit has a garage and an upstairs office. The Garage Lab shares their unit with a co-working space upstairs — basically, they get the garage at all the times, but only the upstairs on the weekend when it is empty.

It’s been around for about 2 years and has about 40 members (~20 of which are active). To be a member it is quite cheap, only €15/month or €10/month if you are a student. They mostly focus on 3D printing and electronics.

The space has several 3D printers, a large work area, and many hand tools. They run CAD classes quite often and are hoping to expand with 3D printing classes and other technical lectures. Our guide was a cool guy named [Axel] who works as a 3D designer at his own company, but loves spreading 3D printing knowledge with the world.

Check out the tour gallery!

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Halloween Knock Box


[Kyle] has been an avid reader of HaD for a long time. In fact, he was inspired by a Halloween knock box from 4 years ago! He saved the link and finally this year, he went ahead and made his own.

So what is it anyway? Well, as the name implies, when you knock on it, it knocks back. And if you knock on it a special number of times, it’ll play a secret tune… It is a great little item to have at any Halloween event — and kids love it!

Design and function of the box is basically the same as the original, with a few modifications — most notably, swapping out the original PICAXE for an ATtiny85 microcontroller. [Kyle] even managed to find the lego skeleton and chains available on eBay. He’s put together a very thorough blog post on it and shared all the code and schematics — so if you’re looking for a last minute Halloween project, this might be it!

Stick around after the break to see the knocking in action!

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