Automate Your Graffiti With The Graffomat!

September 30, 2021 by Jim Heaney 30 Comments

In Banksy’s book, Wall and Piece, there is a very interesting quote; “Imagine a city where graffiti wasn’t illegal, a city where everybody could draw whatever they liked…”. This sounds like it would be a very exciting city to live in, except for those of us who do not have an artistic bone in their body. Luckily, [Niklas Roy] has come up with the solution to this problem; the Graffomat, a spray can plotter.

The Graffomat is, in its creator’s own words, a “quick and dirty graffiti plotter.” It is constructed primarily from wood and driven by recycled cordless drills that pulls string pulleys to move the gantry. The Arduino Nano at the heart of the Graffomat can be controlled by sending coordinates over serial. This allows for the connection of an SD card reader to drip-feed the machine, or a computer to enable real-time local or over-the-internet control.

We are especially impressed with how [Niklas] handled positional tracking. The cordless drills were certainly not repeatable like a stepper motor, as to allow for open-loop control. Therefore, the position of the gantry and head needed to be actively tracked. To achieve this, the axes are covered with black and white striped encoder strips, that is then read by a pair of phototransistors as the machine moves along. These can then be paired with the homing switches in the top left corner to determine absolute position.

Graffomat is not the first automated graffiti machine we’ve covered. Read here about the robot that painted murals by climbing smokestacks in Estonia.

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No, Cat, This Is Not The Litter Box

March 4, 2018 by James Hobson 39 Comments

Hackaday.io user [peterquinn] has encountered a problem with his recently unruly cat peeing under the dining table. Recognizing that the household cat’s natural enemy is the spray bottle, he built an automatic cat sprayer to deter her antics.

The build is clear-cut: an Arduino Uno clone for a brain, an MG995 servo, PIR sensor, spray bottle, and assorted electronics components. [peterquinn] attached the servo to the spray bottle with a hose clamp — ensuring that the zero position is pointing at the trigger — and running a piece of cabling around the trigger that the servo will tug on. Adding a capacitor proved necessary after frying the first Uno clone, as the servo powering up would cause the Uno to reset.

The code is set up to trigger the servo — spraying the cat twice — once the PIR detects the cat for more than ten seconds. After toying with a few options, [peterquinn] is using a 9V, 2A power supply that works just fine. For now, he hopes the auto-sprayer should do the trick. If it somehow doesn’t work, [peterquinn] has mused that a drastic upgrade to the vacuum may be necessary.

Robot Graffiti

September 13, 2017 by James Hobson 11 Comments

There’s talk of robots and AIs taking on jobs in many different industries. Depending on how much stock you place in that, it might still be fair to say the more creative fields will remain firmly in the hands of humans, right?

Well, we may have some bad news for you. Robots are now painting our murals.

Estonian inventor [Mihkel Joala] — also working at SprayPainter — successfully tested his prototype by painting a 30m tall mural on a smokestack in Tartu, Estonia. The creative procedure for this mural is a little odd if you are used to the ordinary painting process: [Joala] first takes an image from his computer, and converts it into a coordinate grid — in this case, about 1.5 million ‘pixels’. These pixels are painted on by a little cart loaded with five colours of spray paint that are able to portray the mural’s full palette once combined and viewed at a distance. Positioning is handled by a motor at the base of the mural controlling the vertical motion in conjunction with tracks at the top and bottom which handle the horizontal motion.

For this mural, the robot spent the fourteen hours trundling up and down a set of cables, dutifully spraying the appropriate colour at such-and-such a point resulting in the image of a maiden cradling a tree and using thirty cans of spray paint in the process.

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Heat-seeking Firebot Drowns Out The Flames

November 10, 2012 by Mike Szczys 10 Comments

This robot can find and extinguish fires automatically. It is the culmination of an Embedded Design class project from last school year. [Dan] and his classmates developed a turret that holds both a spray nozzle and heat sensor which would be a fantastic building block for a real-life tower defense game.

The jewel of the sensor array is a TPA81 thermopile array. Note the use of the term ‘array’ in the name. This is more like eight temperature sensors aligned with each other. By monitoring them all, the direction from which the most heat is coming can be determined. Once it’s zeroed in on the fire getting water to the right place can be a difficult task. That’s where the other sensors come into play. An accelerometer allows the bot to determine the angle of the spray nozzle (a weed sprayer was used in this case). An ultrasonic range finder and few algorithms let the Arduino which drives it all make sure that the arc of the water lands on the hot spot. This is all shown quite clearly in the clip below the jump.

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