The ChalkJET: An Ink Jet Printer For The Streets

August 29, 2014 by James Hobson 12 Comments

Need to do some guerrilla street advertising? What you need is the ChalkJET 9000, an ink jet printer on wheels.

Using two Arduino Duemilanoves for the brains, this little cart features eight cans of spray chalk which can be individually actuated. Small solenoids pull down on levers in order to spray the cans. Encoders on the wheels of the cart keep track of the spacing in between each pixel as the cart gets dragged along.

A small LCD mounted on the handle allows you to select which text you would like to print, but it doesn’t look like manual entry of new words is possible — You’ll need to load up a library while connected to a computer before hitting the streets!

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800 Inches Per Minute At 0.00025″ Resolution

August 28, 2014 by James Hobson 140 Comments

The folks over at PONTECH have just released a pretty impressive opensource PIC32 library for controlling a linear slide at speeds of 800 inches per minute!

PONTECH makes the Quick240 (Quick Universal Industrial Control Kard) which is based on the open source chipKIT platform. It was designed for industrial automation systems, where typically a ladder logic PLC might be used. The benefits to using a system like this is that because it is open, you are no longer stuck with proprietary hardware, and it is much more flexible to allow you to “do your own thing”. Did we mention it is also Arduino compatible?

Using this system they’ve successfully controlled two 8″ Velox slides at a whopping 800 inches per minute with a resolution of 0.00025″ — just take a look at the following video to appreciate how freaking fast that is.

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Home Made Segway Makes use of Balanduino

Impressive Homemade Segway Is The Real Deal

August 25, 2014 by James Hobson 19 Comments

[Kristian] just put the finishing touches on his full size Segway built from scratch.

Back in 2012, he made a small balancing robot using a gyroscopic sensor and a PID controller — you can see the original post here. The cool thing is, he’s basically just scaled up his original project to create this full-size Segway!

It uses two 500W 24V DC motors (MY1929Z2) on an aluminum check plate frame, with the rest of the structure made from steel plumbing and fittings. What we really like is the steering linkage; similar to a real Segway, you pull the handle in the direction you want to turn. He’s accomplished this by putting another length of pipe parallel to the wheels which is connected by an elbow fitting to the handle bar. It’s supported by two pillow block bearings, and in the back is a fixed potentiometer — when you lean the handle bars one way, the pipe rotates, spinning the potentiometer. To make it return to neutral, he’s added springs on either side.

There’s an impressive build log to go along with it, and a great demonstration video after the break.

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Stewart Platform Ball Bearing Balancer

August 22, 2014 by Edward Becker 23 Comments

For their Mechanical Engineering senior design project at San Jose State University, [Tyler Kroymann] and [Robert Dee] designed and built a racing motion simulator. Which is slightly out of the budget of most hackers, so before they went full-scale, a more affordable Arduino powered Stewart platform proof of concept was built. Stewart platforms typically use six electric or hydraulic linear actuators to provide motion in six degrees of freedom (6 DOF), surge (X), sway (Y), heave (Z), pitch, roll, and yaw. With a simple software translation matrix, to account for the angular displacement of the servo arm, you can transform the needed linear motions into PWM signals for standard hobby servos.

The 6 DOF platform, with the addition of a resistive touch screen, also doubled as a side project for their mechatronic control systems class. However, in this configuration the platform was constrained to just pitch and roll. The Arduino reads the resistive touch screen and registers the ball bearing’s location. Then a PID compares this to the target location generating an error vector. The error vector is used to find an inverse kinematic solution which causes the actuators to move the ball towards the target location. This whole process is repeated 50 times a second. The target location can be a pre-programmed or controlled using the analog stick on a Wii nunchuck.

Watch the ball bearing seek the target location after the break.

Thanks to [Toby] for sending in this tip.

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Speedy Drinkmaker Keeps Party Guests Hydrated

August 20, 2014 by Bryan Cockfield 23 Comments

After five weekends of work, [Alex] completed his automatic drink maker, the RumBot. What makes this automated bartender different from others is the fact that it is fast. VERY fast. It can serve drinks to five different locations in as little as 3 seconds per drink. By [Alex]’s estimation, this could keep a party of 100 people going without anyone waiting on a drink.

The RumBot can make either of five pre-programmed drinks at varying levels of alcoholic intensity, ranging from 1 (“Virgin”) to 10. And for that extra push over the cliff, you can turn the knob to 11 (“Problem”).

Drink selection itself is handled by a simple digital I/O on an Arduino with a 1950s-styled user interface. The frame is built out of wood and uses 3D Printed plastic parts. It houses a very robust servo on a ~~belt~~ screw-driven stage to move the drink nozzle, and special sensors placed at either of the five drink locations detect a cup ready to be filled. Any cup placed at any of the positions will automatically be filled based on the RumBot’s settings at any particular time.

Based on the quality of the build and the increased speed of this automatic drink maker, this should be a huge hit at any party. With all the knobs turned to 11 though, it might be a good idea to have a breathalyzer on hand! All of the code and schematics for the project are available at the project site as well.

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Pressure Gauge Used to Monitor Internet Usage

Steam Gauge Keeps Track Of Your Internet Usage

August 19, 2014 by James Hobson 14 Comments

There’s a certain appeal to analog gauges in a vastly digital world. [Ed Konowal] is a Network Operations Supervisor for a school district in Florida — part of his job is to ensure a stable and fast internet connection, so he decided to make an internet usage gauge for his office.

What we really like about this hack is the fact that [Ed] had no idea how to do it. It’s a simple enough idea, right? Google was his friend and Ed started learning about all kinds of things. Raspberry Pi’s and Arduinos, wireless receiver/transmitters, servos and steppers, Python…

After quite a bit of trial and error, [Ed] eventually settled on a wired design which uses a Raspberry Pi running a Python program to poll the internet bandwidth, which in turn calculates the servo position for the dial and sends that number to the Arduino to move it into position. This repeats every 10 seconds. Pretty cool!

Kind of reminds us of this project to make custom gauges using a stepper motor breakout board!

[Thank Justin!]

Beach Buddy Is A Boombox, Phone Charger, And Sunburn Warner

August 18, 2014 by Marsh 6 Comments

When you venture out onto the beach for a day in the sun, you’re probably not preoccupied with remembering the specifics about your sunscreen’s SPF rating—if you even remembered to apply any. [starwisher] suffered a nasty sunburn after baking in the sunlight beyond her sunscreen’s limits. To prevent future suffering, she developed The Beach Buddy: a portable stereo and phone charger with a handy sunburn calculator to warn you the next time the sun is turning you into barbecue.

After telling the Beach Buddy your skin type and your sunscreen’s SPF rating, a UV sensor takes a reading and an Arduino does a quick calculation that determines how long until you should reapply your sunscreen. Who wants to lug around a boring warning box, though?

[starwisher] went to the trouble of crafting a truly useful all-in-one device by modifying this stereo and this charger to fit together in a sleek custom acrylic enclosure. There’s a switch to activate each function—timer, charger, stereo—a slot on the side to house your phone, and an LCD with some accompanying buttons for setting up the UV timer. You can check out a demo of all the Beach Buddy’s features in a video below.

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