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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Hackaday Links: August 25, 2013


[Adrian] came across a treasure trove of 507 mechanical device designs. It didn’t seem quite right for a Retrotechtacular post, but we wanted to share it as it’s a great place to come up with ideas for your next Rube Goldberg machine.

Biking with headphones is dangerous. That’s why [J.R.] built a handlebar enclosure for his Jambox Bluetooth speaker.

While dumpster diving [Mike] found a Macbook pro. It was missing a few things, like a keyboard, touchpad, battery, ram, and storage. He borrowed a power supply to test it out but without the keyboard there’s no power button. He figured out the traces on the motherboard which turn it on when shorted.

[Mateusz] want to let us know about the Hercules LaunchPad. Like the other TI Launchpad offerings it’s an all-in-one dev board. The Hercules line features a couple of flavors of dual-core ARM chips. Can you believe the dev boards you can get for under $20 these days?

After seeing the ammo can sound system about a month ago [Ilpo] was inspired to share his ammo can PC case with us.

And finally, here’s a way to display your Bitcoin mining rig for all to see. This system was laid out in an antique frame and hung on the wall.

External pinball controls for an Android tablet


This hack, which adds external flipper controls to Android pinball, is a great way to cut your teeth at Android hardware hacking.

[Ruben] decided to go with the TI Launchpad for this project. The MSP430 dev board offers serial communications via a USB connection, but it’s not quite as easy as just finding the right cable. His tablet does support USB On the Go (OTG), but the board identifies itself as an ACM device which needs to be handled differently. In order to get the tablet talking to the Launchpad he compiled a CDC_ACM module for the Linux underpinnings that make up every Android OS. In this case the module is tailored for the Allwinner A10 chip inside his model of tablet, but it shouldn’t be too hard to adapt his guide for other processors.

Of course you could go a different route and use Bluetooth for connectivity. We’ve seen several gaming peripherals that use this technique with Android devices.

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MSP430 touchscreen piano


[Rohit Gupta] wrote in to share this touchscreen piano project he built around the TI Launchpad. It provided a way for him to explore using a resistive digitizer found on a lot of mobile devices. These are simply stuck to the top of LCD screens and replacements are inexpensive, but salvaging one from old hardware is an option as well.

The first thing he did was to test the four outputs of the digitizer with his multimeter. Logging the changing resistance will help make sure you’re reading the correct wires and are able to zero in the settings before you start coding. [Rohit] uses the ADC on the MSP430 chip to read from the screen. He went with the algorithm from one of TI’s app notes to convert the readings in to X and Y coordinates.

He separated the screen into seven columns, each generating a different tone. Touching higher or lower on that column will alter the pitch of the note produced. You can hear an example of this in the demo after the jump.

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Lord Vetinari’s clock strikes again


Inspired by the maddening timepiece from Discworld, this clock keeps time, but anyone watching the seconds tick by may be mentally unstable for it. [Renaud Schleck] built the stuttering clock using very few components. He undertook the build after being inspired by the version which [Simon Inns] built.

The clock itself is a run-of-the-mill item which uses one battery to keep time. We’re always impressed by how these dirt-cheap things remain so accurate over the long haul — but we digress. The method of attack uses coil injection to drive the hands. [Renaud] used one of the microcontrollers from the MSP430 Launchpad, along with the clock crystal which also shipped with the kit, to gain control of the mechanism. The crystal triggers an interrupt which does the actual time-keeping. The seconds hand is driven rather sporadically based on an algorithm explained in his write-up.

You can watch the uneven ticking in the video after the break. Despite that visually disturbing functionality, the short and long ticks balance each other and the correct time continues to be displayed.

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Stellaris Launchpad shield shows good fabrication technique


Here’s an LED and Button shield for the Stellaris Launchpad (translated) which you can fabricate at home. It gives you access to a 5×5 matrix of LEDs, and adds four more buttons. In order to cut down on the number of I/O pins required to operate the lights [Cosimo] is using the concept of Charlieplexing. This lets him get away with just six driver pins and four button pins.

It’s not just the finished product that interests us here. The fabrication itself is worth clicking through to his project post. What initially caught our eye is the use of Kapton tape as an insulator so that clipped off LEDs could be used as jumpers flat against the top side of the board before populating the LEDs themselves. After those are soldered in place he masks them off, as well as the button footprints, and uses spray paint to protect the top side of the board. The final look is more polished than most at-home project boards.

Hackaday Links: November 29th, 2012

EMC2 CNC keyboard labels

If you’ve got a dedicated computer running EMC2 for CNC control you may be interested in these keyboard labels. [Rich] mentions that they use the labels for their engraver at the Connecticut Hackerspace. Just print them out and glue them in the face of the keys.

Dev board seminars and freebies

[Mike] wrote in to tell us STM is giving away samples of the STM32 F3 Discovery again. But you can also get in on some free seminars. One is an online webinar for TI’s Launchpad family, the other is for the F3 Discovery board and is being held all around the US.

Replacing batteries with USB power

[Johan] didn’t want to use batteries for the light on the microscope he uses when working with SMT parts. He added a few components with let him power the device from USB instead.

MSP430 VU meter uses FFT

Here’s an MSP430 using Fast Fourier Transform for signal processing. There’s very little explanation, but apparently this collection of FFT related material was used heavily in the project. [via Reddit]

Cell Racr

If you’re looking for a new office game you might consider Cell Racr. It pits your cellphone’s vibrating motor against everyone else’s. Just place the phone on an incline and repeatedly dial its number to advance toward the finish line.