Double-pendulum Spray Gives This Graffiti Bot Some Style

Here’s an art exhibit that does its own painting. The Senseless Drawing Bot (translated) uses the back and forth motion of the wheeled based to get a double-pendulum arm swinging. At the end of the out-of-control appendage, a can of spray paint is let loose. We’re kind of surprised by the results as they don’t look like a machine made them.

The video after the break gives a pretty good synopsis of how the robot performs its duties. The site linked above is a bit difficult to navigate, but if you start digging you’ll find a lot of build information. For instance, it looks like this was prototyped with a small RC car along with sticks of wood as the pendulums.

We can’t help but be reminded of this robot that balances an inverted double pendulum. We wonder if it could be hacked to purposefully draw graffiti that makes a bit more sense than what we see here?

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Do You Have What It Takes To Make Lumber Keep Time?

[Frank] sent in a link to this fantastic wooden clock. The design was dreamed up by [Clayton Boyer] and he’s got full-sized templates for sale on his site. We’ve marveled at his creations in the past, having featured his useless machine that was made from wooden gears. This “Bird of Paradise” clock steps up the complexity quite a bit, creating a timepiece without a case to show off the beauty of all of those teeth.

We wondered what goes into building one of these yourself. From the FAQ page it seems you could get by with a scroll saw, drill press, Dremel, and sander. That’s the medium-tech method, but you could opt to scan the plans in order to laser cut your parts, or just use hand tools. But in addition to building tips, there’s advice on how to fine tune clocks that don’t want to keep running, thoughts on finishing the wood parts, sanding, tweaking the teeth, and much more. It’s no secret we have a love for digital clock projects, but there’s something very seductive about a design like this that uses no electricity. Don’t miss the clip after the break to see what we mean.

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Building An Electromagnetic Pendulum Clock

electromagnetic_pendulum_clock

[Stephen Hobley] has been experimenting with an electromagnetic pendulum in order to build himself a clock. Through the course of his experiments, he has learned quite a bit about how pendulums function as well as the best way to keep one moving without the need for chains and weights, which are typically associated with these sorts of clocks.

His first experiments involved driving a simple pendulum with a pulse motor. He discovered that the easiest way to keep the pendulum moving was to use a coil to detect when the it reached the equilibrium point, pushing it along by sending a small pulse to that same coil. He noticed that he could keep the pendulum moving at a pretty good tick if he triggered the magnetic coil every third pass, so he implemented an Arduino to keep count of passes and apply the appropriate force when needed.

He has been making pretty decent headway since his first experiments and now has nearly all of the clock works assembled. Crafted out of wood, he uses a 15-tooth primary drive ratchet, which powers two 60-tooth gears responsible for keeping track of seconds, as well as a pair of larger gears that track the minutes and hours.

It’s looking good so far, we can’t wait to see it when finished.

Stick around to see a quick video demonstration of the clock with all of its gearing in action.

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LEGO Pendulum Clock

Put a case around it and it would be a grandfather clock but for now it’s a pendulum clock made from LEGO pieces. The video after the break shows a great overview of the build. You can see the workings at several different angles, as well as a clip that has been sped up to show the movement of the weights over time. One weight, made from dead AA batteries, drives the clock and the other weight switches the winding motor. That motor acts to automatically wind the clock when the drive weight reaches the end of its rope.

This is a nice departure from the majority of clock projects we see as it utilizes mechanical concepts instead of electronic. Most of [Pmroskelly’s] build details are shared as comments on the Picasa album found at the link above. There are also some other videos such as the one showing how the escapement works.

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Balancing Inverted Pendulums

The robot above can balance an inverted pendulum. But wait, it gets better. It can balance an inverted pendulum that is articulated in the middle like the one seen above. Wait, wait, wait… it gets even better. It can start with the pendulum hanging below the sliding carriage, flick back and forth to get the two segments swinging, and then come to equilibrium with the pendulum as seen above. Once there, it can recover from a bit of a shove, like some of the big boys. Very impressive, even when compared to two-wheeled balancers. See for yourself after the break.

We don’t have very much information on how this works. We do know that it was a seminar paper from a student at the University of Stuttgart but the rest is pretty much a mystery. Does it use visual processing? What kind of controller is driving this thing? We want to know the details but haven’t yet found a copy of the paper. If you know where we can get our mitts on it please leave a comment below.

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Wireless Painting

[Tom Shannon] uses science as part of his art. One of his methods when painting is to use this radio controlled paint pendulum. He gave an interview at his studio, which we’ve embedded after the break, and goes into detail about this device. It has six different reservoirs that hold the paint colors. Each gravity-fed canister connects to a central nozzle with flexible tubing. The hand held control box has a slider for each color that moves a servo pinching each supply tube. This ingenuity keeps him creating even though Parkinson’s Disease has started to manifest itself with tremors in his hands.

It’s hard to make out the paintings seen above, but the ones on display in the video are pretty amazing. He mentions that anything can be loaded into the hoppers, including tomato sauce. Is anyone else thinking about large scale pizza constuction? This also reminds us of the mechanical bartenders we’ve seen in the past. Continue reading “Wireless Painting”