Paraffin Oil and Water Dot Matrix Display

In preparation for Makerfaire, [hwhardsoft] needed to throw together some demos. So they dug deep and produced this unique display.

The display uses two synchronized peristaltic pumps to push water and red paraffin through a tube that switches back over itself in a predictable fashion. As visible in the video after the break, the pumps go at it for a few minutes producing a seemingly random pattern. The pattern coalesces at the end into a short string of text. The text is unfortunately fairly hard to read, even on a contrasting background. Perhaps an application of UV dye could help?

Once the message has been displayed, the water and paraffin drop back into the holding tank as the next message is queued up. The oil and water separate just like expected and a pump at the level of each fluid feeds it back into the system.

We were deeply puzzled at what appeared to be an Arduino mounted on a DIN rail for use in industrial settings, but then discovered that this product is what [hwhardsoft] built the demo to sell. We can see some pretty cool variations on this technique for art displays.

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Robot Does the Worm to Get Around

Walking, jumping, rolling, flying, swimming – robotic locomotion is limited only by the imagination of the inventor. [Roger Rabbit] apparently has a pretty vivid imagination, because he’s building robots that move like worms.

2823251454881775155inchworm-robot-thumbnailVersion 1 of [Roger]’s robot is only semi-vermiform and is more of tube climber. It has a pair of 3D-printed pantographs that expand and contract with servos and move along the robot’s axis on a stepper-driven lead screw. An Arduino reads sensors and coordinates the expansion of the pantographs to grip the internal diameter of a pipe and push the worm-bot along. It’s a slow but effective way to get around in the limited confines of a pipe.

The next iteration, dubbed [Wolly],  is much more worm-like and not restricted to pipe-running. It has four expandable triangular frames connected to each other with rack-and-pinion backbones. The first frame contracts, the racks push it forward, it expands, the next contracts, and soon it’s doing the worm across the floor. Still slow, but pretty neat to watch, and you can see how it can be steered. It might even be able to roll around its long axis, and it’d make a decent tube climber as well.

This creepy autonomous worm-bot seems very similar to [Wolly], but aside from that we haven’t covered too many robots like these. There’s a lot of thought and effort in these worm-bots, and we’re keen to see where [Roger] takes this unique robot body plan.

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Laser cut pumps

As the video above shows, [Zach Hoeken] is continuing to improve on his peristaltic pump design. The moving parts in peristaltic pumps never contact the fluid being moved. Instead, they interact with the outside of the tubing that’s carrying the liquid. In [Zach]’s design, multiple skate bearings roll across the outside of the silicon tubing, squeezing the liquid through. You can get a better idea of how this works by watching the first video. The newer version appears to be pumping much better. We’re not sure if that’s because of faster motors or from switching to two bearings instead of three. This definitely looks like a good choice if you’re planning on building your own cocktail robot. You can find the plans on Thingiverse.