Hackaday Links: December 11, 2011

Drilling square holes

We’re still a bit baffled by the physics of this, but apparently it’s possible to drill a square hole with a round bit. This video shows square holes being milled using a cutter which is offset from the center of the bit. [Thanks Jordan]

LED Motorcycle headlight driven by mains

[William] found a way to use a big capacitor and bridge rectifier to run this H4 LED headlight bulb in a mains sconce lamp.

Electronic slide whistle

Here’s an electronic instrument that [Dorian] made. It uses a linear potentiometer and a button and works much like a slide whistle would.

Robot rocks out to Daft Punk

[Adrian] didn’t just make a robot arm out of CD cases and a mints tin. He built the arm, then made a music video featuring it.

More light-pipe sensor experiments

[Uwe] has been working on an input sensor using a flexible light tube. It is a similar idea to these optical flex sensors, but [Uwe] tried several variations like filling the tube with alcohol.

Internet controlled robotic arm

The guys over at Rusty Nail Workshop have put up an Internet controlled robotic arm for your amusement. While you’re waiting for the turkey to be done (or, you know, working), try your hand at moving some LEGO pieces around with a remote-controlled robotic arm.

The build log goes through the parts needed for the build. The arm itself is a Lynxmotion AL-5D, a heavy-duty device that’s far more capable and looks a lot better than our old Armatron.

The arm is controlled by an Arduino Uno. The Arduino is connected to the arm’s servo controller. Movement commands are received by an Ethernet shield and translated into servo commands. The entire build runs independently of a computer just like this project’s inspiration, the Orbduino.

Of course you can imagine the mayhem that would ensue if multiple people tried to take control of the robot simultaneously. A bit of code on the project’s website makes sure only one person has control of the robot at any given time. Check out what somebody else is building out of LEGO blocks with a Waldo. If you’re lucky, you’ll be able to knock that work down.

I’ll see your Launchpad controlled arm and raise you Arduino controlled autonomy

This OWI robot arm has been hacked to add position sensors and Arduino control. [Chris Anderson] took one look at the Launchpad controlled OWI from earlier today and said “wait a minute, I’ve already posted my own version of that project”. Well, that will teach him not to tip us off about his hacks!

The position control is a really nice addition. Potentiometers added to each of the joints (shoulder, elbow, and wrist) can be read by the ADC pins on the Arduino. Just a bit of calibration will let the microcontroller board know the position of the arm at any given time. The control technique is the same as the Launchpad hack, with one glaring drawback. [Chris] is using the Adafruit motor driver shield. It uses L293D H-bridge chips, but it only has four channels. There are five motors on this arm, so the video after the break shows it moving around without any outside instruction, but you won’t see it grab onto anything since the Arduino can’t move the gripper!

Still, the position feedback makes the case for this version. Just remember to order an extra chip if you want full control.

[Read more...]

TI Launchpad adds computer control to a robot arm

[Eric Gregori] had an OWI535 toy robotic arm. Although cheap (coming it at around $30) the arm is only set up to be used via a wired control box. [Eric] knew he could do better by adding computer control via a TI Launchpad and motor driver peripheral.

The arm has shoulder, elbow, and wrist joints, a rotating base, and a gripper. All of these are actuated by 3V DC motors and have just two control wires. [Eric's] motor driver add-on for the Launchpad works great in this case. It’s got three FAN8200 dual motor driver chips on board so it can control up to six motors. Once he made the hardware connections it’s just a matter of sending the commands to the Launchpad via its USB interface, but you will also need to use a larger microcontroller than comes with the Launchpad. Here he’s chosen an MSP430G2553.

In order to make things a little bit more fun he also wrote a GUI for controlling the arm from the computer. He used RobotSee, a programming language that lets you use an image of the hardware, and overlay the controls on top of it. Now he just needs to make this into a web interface and he can have a smartphone controlled crane game.

Don’t forget to check out the video after the break. [Read more...]

Robotic arm follows the movements of your own limbs

[Alejandro] and his friends recently finished a first prototype of scratch-built robotic arm. They’ve got some nice electronics bench equipment for use with a project like this, but for the actual fabrication work it’s off to the kitchen.

As you can see in the video after the break, they’re using PVC as the stock material in this build. Flat sheets are produced by slitting a PVC pipe down the middle, warming it in oven until soft, then compressing it between two floor tiles with a big jug of water used as a weight for the makeshift press. Mounting holes for the servo motors that make up the joints are drilled with a hand drill, and the assembly was affixed to an old CD as a base.

Once assembled they wired it to the control circuitry and build a set of sensors that you wear on your arm. Now your elbow, wrist, and pointer finger are in control of the servos. A demonstration of this functionality starts around two minutes into the video.

We’ve seen other examples of robot arms built without the use of machine tools. This arm made out of ShapeLock plastic is one of the most interesting examples.

[Read more...]

Hackaday links: February 7, 2010

Bot gives head to passersby

This free range robot was spotted at this year’s Kinetica Art Fair. You can place your hand above it and it will stop and pour you a beer. That’s if you consider 7/8 of a glass of head ‘a beer’.

Photo booth adds fun – consumes floor space

Face it, photo booths are fun, and if they’re free a lot of people will use them. This particular booth was built in some guy’s apartment, adding the fun but eating up floor space. But this would be a great build for your next group gathering, just like the Crushtoberfest. [via DVICE]

More human through-hole design

[Fridgehead] stuck and 5mm LED in his earlobe and then used a microcontroller to make it pulse. He’s got quite a mop and that’s where he hides the black controller pack. The next version should be RGB and the smallest surface mount packages he can solder. At least this isn’t disgusting like the LED nipple ring.

Chandelier your wife will never let you install

This 300 LED chandelier uses epoxy coated wires draped around the light ring to resemble a more traditional crystal light fixture. It’ll still be a hard sell if you want to hang this over the dinner table. [via Gizmodo]

A touch of copper

[Zombie84] built a prototype of a robot arm out of copper pipe. There’s not much info here, but you can see some wires in the wrist that appear to function as tendons. This reminds us of the characters from 9.

Arduino powered CD changing robot

arduino cd robot

[ross], a reader is working on a CD changing and ripping robot. The arm picks up a CD and the platform then rotates, stopping in front of the tray to drop the CD. A JB welded tire pump provides the vacuum pick up, while a brake light acts as a resistor to trick a PC power supply into operation. A Motor Shield beefs up an Arduino in order to drive the servos.


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