Beautiful Sidewalk Graffiti Machine

Our hero [Alex] just built a sidewalk graffiti machine, and it’s a beauty to behold, so make sure you check out the video below the break. But don’t neglect [Alex]’s blog, and the build videos throughout. (Nice t-shirt in the wheel-making video, BTW.)

The machine itself is basically a two-meter wide printer where the roller is replaced with drive wheels. The frame, made of plywood, looks great and helps keep the machine light weight. Everything is done with DC motors and timing belts, which means motor encoders and closed-loop control in the firmware. It connects via a WiFi serial bridge, made with an ESP8266, to [Alex]’s cell phone.

Everything, from plans to software, is available on [Alex]’s GitHub for the project.

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Robot Listens To Commands–Literally

Where you might see a can, [Adam Kumpf] sees a robot. [Adam’s] robot (named [Canny]) doesn’t move around, but it does have expressive eyebrows, multicolored eyes, and a speaker for a mouth. What makes it interesting, though, is the fact that it receives audio commands via the headphones it wears. You can see [Canny] in action in the video below.

The headphones couple audio tones to [Canny’s] microphone using AFSK (audio frequency shift keying). [Canny] uses an opamp to bring the microphone level up and then uses a 567 PLL IC to decode the audio tones. [Adam] selected two clever frequencies for the mark and space (12345 Hz and 9876 Hz). In addition to being numerically entertaining, the frequencies are far enough apart to be easy to detect, pass through the headphones with no problem, and are not harmonically related.

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Creating Art In A Robot That Tastes With Its Feet

[Sarah Petkus] started off her career as a visual artist with traditional mediums. She has a webcomic called Gravity Road, but somewhere along the line she wanted her creations to come alive. These characters are robots – artistically designed robots – and turning this type of art into a real object isn’t something that happens very often.

Robots usually aren’t art. A Roomba is just a vacuum cleaner that’s meant to turn on a dime, thus the circular shape. The welding robots in a car factory aren’t art, they’re only tools to assemble cars. These are just devices built for a single purpose, and art is for any or every purpose. It’s not something you can really design, but you can engineer a few interesting solutions.

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Shark Vs. Robot

In laymen’s terms they built a shark-chasing robot. You can guess what happened next…

The back story is a little more reputable. I recently attended the Center for Marine Robotics meeting at the Woods Hole Oceanographic Institution (WHOI) and learned about a very interesting robot. For the Discovery Channel’s Shark Week the network partnered with [Amy Kukulya] at WHOI to develop an autonomous underwater vehicle (AUV) that locates, follows, and films sharks in their natural habitats, swimming, patrolling, doing their thing.

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Hacklet 87 – Roomba Projects

First introduced in 2002, The iRobot Roomba was conceived as a robotic vacuum cleaner. Just about every hacker, maker, and engineer out there immediately wanted one. The Roomba proved to be more than just a vacuum though; it was the perfect base for any household robotics project. Before long Roombas were being hacked to do way more than sweep your floor. iRobot recognized this, and added a hacker friendly serial port to later model Roombas. They even released a vacuumless version called the iRobot Create. Thousands of projects have literally ridden on the wheels of the Roomba. This week’s Hacklet is all about Roomba projects.

roomba1We start with [fuzzie360] and Poor Man’s Raspberry Pi Turtlebot. [Fuzzie360] has their Roomba running Robot Operating System (ROS). ROS actually is running on an on-board Raspberry Pi. While Willow Garage may be out of business, ROS lives on as an open source project run by Unbounded Robotics. Installing it can be a chore though. While [Fuzzie360] hasn’t given a full tutorial, they have offered to give advice if and when you get stuck.

A Raspberry Pi would be overkill for the simple suite of sensors built into the Roomba, but it’s perfect for [fuzzie3680’s] modified setup with a Microsoft Kinect. [Fuzzie360’s] goal is to have a robot that can vacuum the hostile territory of a university apartment.

 

roomba2Next up is [Sircut] who upgraded his Roomba’s power cell. Early Roombas were designed to use Nickle Metal Hydride (NiMH) batteries. The individual cells are built into a proprietary iRobot battery pack. NiMH can’t hold a candle to Lithium Ion batteries though. Lithium Ion cells are very common these days in devices like cell phones and laptops. In fact, [Sircut] used 18650 sized laptop cells for this upgrade. [Sircut] also added the essential LiIon battery protection circuit to make sure those cells stay happy. A voltmeter provides a visual reference that the batteries aren’t becoming overcharged. An upgrade like this will likely double the Roomba’s runtime, but it does come at a cost. Roomba’s original charge dock can no longer be used as the on-board charge circuitry isn’t designed for LiIon battery charge algorithms.

roomba3Next is [Marcel Varallo] with Robot Wars for the Commuter. How does the IT department blow off steam? Fighting robots of course! Unfortunately, [Marcel’s] coworkers aren’t all programming mavens. Hopefully some programming is in the cards for them down the road. For now though, [Marcel] has created a robot fighting league using nearly stock Roomba robots. Each bot gets a set of 3 balloons and 3 pins. A balloon represents a life. Once your lives are all popped, you’re dead! [Marcel] also created an upgrade system where winning ‘bots can move on to stronger weapons like flamethrowers. During his research, [Marcel] found out that the brushes in his Roomba are powerful enough to sweep dust and debris up without the vacuum enabled. So he’s disabled the vacuums for longer cleaning battle times.

roomba4Finally we have [Fredrik Markström] and ESP8266 controlled Roomba. [Fredrick] is hacking an ESP8266 module to be the main computer of this little Robot. Of course, a ‘8266 means it will be carrying WiFi, so this robot needs to have a web interface. [Fredrik’s] first problem was powering the ESP8266. The Roomba’s battery runs around 15 volts, which is definitely not friendly to the 3.3 volt ESP8266. A switching DC to DC converter was in order, and [Fredrik] found the perfect candidate on eBay. The ‘8266 will control the Roomba through the serial interface included on all the current models. [Fredrik] has big plans for this ‘bot, including navigation and advanced vacuuming algorithms.

If you want to see more Roomba projects, check out our new Roomba project list! If I missed your project, don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Alvaro Prieto’s Laser-Shooting Robots

[Alvaro Prieto]’s talk at the Hackaday Supercon began with a slide that asks the rhetorical question “Why Laser-Shooting Robots?” Does a rhetorical question need an answer? [Alvaro] gives one anyway: “Because lasers are awesome.” We concur.

But it doesn’t hurt that DEFCON holds a laser robot contest to give you an excuse, either. You see, [Alvaro]’s laser-wielding robot was the First Place finisher in the 2014 DEFCONBOTS contest, and a much more ambitious design came in third in 2015. His Supercon talk is all about the lessons he’s learned along the way, because that’s really the point of these contests anyway, right?

“I have no idea what I’m doing.”

[Alvaro] started off with a disclaimer, but when [Alvaro] says he doesn’t know what he’s doing, what he means is that he hasn’t received formal training in building laser-wielding, autonomous turret robots. (How did we miss that class in school?)

iterations

He’s a true hacker, though; he didn’t know what he was doing when he started out but he started out anyway. [Alvaro]’s takes us from the first prototypes where he used servo motors with inadequate angular resolution mounted to balsa wood frames that he (obviously) cut with a knife by hand, through laser-cut frames with custom gearing and stepper motors, all the way to his DEFCONBOTS 2015 entry, based on OpenBeam aluminum extrusions and using professional laser-show galvos capable of swinging the beam around to thousands of points per second.

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Toward The Optionally Piloted Aircraft

Aviation Week and Space Technology, the industry’s leading magazine, has been publishing “pilot reports,” on new aircraft for decades. Its pilot report on an aircraft called Centaur ⁠was the first in which the pilot doing the test never touched the controls. Centaur is an optionally-piloted aircraft, or OPA.

The reporter conducted the test while sitting in the back seat of the small, twin engine aircraft. Up front sat a person acting as the safety pilot, his arms calmly resting on his lap. Sitting beside him, in what is ordinarily the co-pilot’s seat, was an engineered series of linkages, actuators, and servos. The safety pilot pulled a lever to engage the mechanisms, and they began moving the pilot’s control stick and pressing the rudder pedals. The actuators are double and redundant; if one set fails another will immediately take over. The safety pilot can disengage the mechanism with a single pull of the lever if something goes wrong; unless something goes wrong he does not touch the controls.

In the back seat, the “operator,” commanded the plane through a laptop, using an interface identical to that of the ground control station for an unmanned vehicle. Through the screen, he could change altitude, fly to waypoints, takeoff or land. Pushing the “launch” button began an autonomous takeoff. The computer held the brakes, pushed the throttles forward, checked the engines and instruments, and released the brakes for the takeoff roll. The plane accelerated, took to the air, and began to climb out on a semi-autonomous flight.

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