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.

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ATtiny Hacks: ATtiny45/85 Servo Library

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Servo8bit is a library for AVR microcontrollers that allows you to drive servo motors without the need for a 16-bit timer. Obviously, this is quite useful for smaller chips that only have 8-bit timers and it is specifically targeted at the ATtiny45 and ATtiny85 microcontrollers. The library offers 256 steps of resolution, and can drive up to five servos at one time. Servo control pulses can be generated between 512 and 2560 microseconds and if you don’t mind increasing the time between these pulses [Liya] says it would be possible to increase the 5-servo limit.

The library is quite easy to use, but in its current state it would take just a bit of work to port to another device. It’s been written for an 8 Mhz clock signal with PortB used to drive the motors. Using find-and-replace to change the PORTB keywords to use a DEFINE variable should be easy enough, but we don’t know how hard it would be to change the clock frequency.

We wonder if it’s possible to make this a slave device, perhaps implementing a 1-wire protocol?

Motorized Blinds Put Control At Your Fingertips

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While [Bremster] likes the view from his office window, he often needs to get up and adjust the blinds several times throughout the day in order to keep the glare from killing his eyes. Like any other enterprising hacker, he decided that constantly adjusting them was too repetitive, and that he could automate the process with electronics.

He thought that RC car servos would be a great choice to control the blinds, since they are cheap and the geared drive system offers a lot of torque at low speeds. After modifying the servos to enable continuous rotation, he set off to the hardware store in search of a way to mount them to the blinds’ looped cords.

After mounting some nylon spacers with rubber grommets on the servo arms, he installed them into a set of brackets he built and gave the blinds a spin. Now, he can easily control his blinds from the comfort of his desk with the simple flick of a switch – that’s the kind of laziness ingenuity we can respect!

Continue reading to see a quick video of his motorized blinds in action.

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Easily Movable RFID Door Lock Is Great For Dorm Rooms

One of the first things that [Eric] hacked together when he got to college was an RFID door locking system. He found that he was often in a rush to get in and out of his dorm room, and that using a simple wireless key was a great way to streamline his days.

Over the years, he has refined his design, and while his original prototype was functional, it was a bit rough around the edges. In the video posted on his site, he thoroughly explains how his system was built, and shows off the revisions he has made over time. One key consideration when building this system was the fact that the installation had to be non-permanent. Since schools typically frown on physically altering your rooms, he found a non-intrusive means to mount his system in the way of zip ties and foam board.

His RFID door lock looks to work quite nicely, and we especially like the inclusion of the reed switch to ensure that the system knows if the door has been opened or not. If you have about half an hour to spare and are interested in building an RFID entry system of your own, be sure to check out [Eric’s] video below for all the details.

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Schäuble Jr Aims To Take Away Your Privacy!

[Mnt] wrote in to tell us about this 360 degree array of cameras featured on [Codeninja]. This has to be one of the most impressive arrays of cameras and sound equipment that we’ve seen at Hack a day.

The array is capable of 360 degree x 140 degree panoramic views using the 9 cameras arranged in a circle around the base. Impressive in itself, these cameras are all capable of both pan and tilt rotation via and Arduino-controlled servo setup. It also has a native 360 degree camera mounted on top of everything for calibration purposes and IR-LED illumination capabilities.

On top of all of this, the camera array also features audio capability with a 9-microphone setup, presumably one for each camera. This, coupled with piezoelectric speakers should provide for echolocation capability. Although jokingly called the “Schäuble Jr.” after a German politician, we’re not sure of the true purpose for this “sensor array.” We can only hope that it will be used for good. A very impressive build, it will be interesting to see what comes of it.

Morphing Hexapod Has Us Drooling

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Hexapod robots seem to be a dime a dozen lately, but we think you will be hard pressed to not be wowed by [Zenta’s] latest creation. He’s built a bunch of hex and octopods before, but hasn’t tried building anything quite like this.

His MorpHex bot might look like your standard hexapod, but once it gets moving, you can see that it’s quite unique. Utilizing over 25 servos driven by a single ARC-32 controller, MorpHex moves in smooth, fluid-like motions, making it almost seem like it’s alive. The inner portion of the body can fan out, extending the overall length of the bot, though it’s more meant to allow the bot to morph into a ball and back, rather than increase its size.

In the teaser video below, you can see MorpHex in action, with its parts flowing together more like a jellyfish than any sort of land animal. While [Zenta] is continuing to work on MorpHex’s sphere-morphing capabilities, we think it would make for an awesome and creepy spiderbot!

[Thanks, weaz]

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Head-to-head Mountain Climbing From The Safety Of Your Game Room

Why risk frostbite and altitude sickness when you can marvel at the view from atop your own mountain climbing game?

[Jeff] built this delightful piece which you can see in action after the break. he combined several very simple ideas and he did it really well. The climbers are both mechanical. They grip the mountain’s face (which is covered with of carpet) with a tack pointed downward on the end of each limb. Their motion is provided by two tiny servos that make up the body of the climber. The two potentiometers in each controller directly affect the movement of the top and bottom limbs. The game plays music during the contest, and precisely detects a winner by sensing when an arm comes in contact with the metal snow cap at the summit.

Obviously weight was an issue during the design process. After some hemming and hawing [Jeff] decided to tether the climbers in order to avoid rolling a battery into each. But he overcame the issue with weighted cable management on the inside of the mountain.

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