Lego Drawing Machine Draws Block Shapes Best

Lego-drawing machine

Loving to draw but deathly afraid of pen ink, [Marcel] came up with a little drawing machine made out of Lego that will do it for him. It’s not a very complicated build but it does have several different components arranged such to complete a task, and that in itself is cool. Oh yeah, just kidding about the “afraid of pen ink” thing.

RC Car Servos are used to drive the pen in the X and Y directions. These servos only have a 180 degree range of motion which is not enough to move the pen very far. To increase the pen’s travel distance, [Marcel] attached a large gear to the servo which rotates a much smaller gear that rides on a rack gear attached to the bed. A Lego hinge takes the place of a Z axis and is used to set the height of the pen that is strapped to the machine via rubber band.

In order to make the machine draw, the user moves an analog joystick. The changing resistance values of the joystick’s potentiometers are measured by an Arduino. The Arduino then moves each servo to the appropriate position using PWM. If you’d like to know how to do this, check out the Knob Tutorial.

If you’re not ready to l’eggo your Lego drawing machines, check out this super complicated creation or this arm emulator that draws the Mona Lisa.


Beating Simon


Virtually everyone has played Simon, that electronic memory game from the 70s, but who among us has actually beaten it? That was the goal of [Ben] and his 7-year-old daughter, and after a year of work, an Arduino, some servos, and a few Lego bricks, they’ve finally done it.

Instead of the large original Simon, [Ben] is using a key chain version of the game: much smaller, and much easier to build a device to sense the lights and push the buttons. The arms are made from Lego bricks, held up with rubber bands and actuated with two servos mounted on a cutting board.

To detect Simon’s lights, [Ben] connected four phototransistors to an Arduino. The Arduino records the pattern of lights on the Simon, and activates the Lego arms in response to that pattern. [Ben]‘s version of Simon has only a maximum of 32 steps in the final sequence, but that still means each game takes 528 button presses – and a lot of annoying beeps – to complete.

Videos below.

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Hackaday Links: June 8, 2014


Yes, dogfighting with RC planes is cool. You know what’s even cooler? RC jousting. Considering these eight foot long planes are probably made of foam board or Depron, they’ll probably hold up for a fairly long time. The perfect application of RC FPV.

Home automation is the next big thing, apparently, but it’s been around for much longer than iPhones and Bluetooth controllable outlets and smart thermostats. Here’s a home automation system from 1985. Monochrome CRT display panel (with an awesome infrared touch screen setup), a rat’s nest of wiring, and a floor plan drawn in ASCII characters. It’s also Y2K compliant.

Here’s an idea for mobile component storage: bags. Instead of tackle and tool boxes for moving resistors and other components around, [Darcy] is using custom bags made from polyethylene sheets, folded and sealed with an impulse sealer. It’s not ESD safe, but accidentally zapping a LED with an ESD would be impressive.

Need a stepper motor test circuit? Easy, just grab one of those Polulu motor drivers, an ATtiny85, wire it up, and you’re done. Of course then you’re troubled with people on the Internet saying you could have done it with a 555 timer. This one is for them. It’s a 555, some wire, and some solder. Could have done it with discrete transistors, though.

Someone figured out Lego Minifigs can hold iDevice charge cables. +1 for the 1980s spaceman.

Remember that “electronic, color sensing, multicolor pen” idea that went around the Internet a year or so ago? It’s soon to be a Kickstarter, and man, is this thing full of fail. They’re putting an ARM 9 CPU in a pen. A pen with a diameter of 15mm. Does anyone know if an ARM 9 is made in that small of a package? We’ll have a full, “this is a totally unrealistic Kickstarter and you’re all sheep for backing it” post when it finally launches. Also, this.

Turning Lego Into A Groove Machine


Last weekend wasn’t just about Maker Faire; in Stockholm there was another DIY festival celebrating the protocols that make electronic music possible. It’s MIDI Hack 2014, and [Kristian], [Michael], [Bram], and [Tobias] put together something really cool: a Lego sequencer

The system is set up on a translucent Lego base plate, suspended above a webcam that feeds into some OpenCV and Python goodness. From there, data is sent to Native Instruments Maschine. There’s a step sequencer using normal Lego bricks, a fader controlling beat delay, and a rotary encoder for reverb.

Despite being limited to studs and pegs, the short demo in the video below actually sounds good, with a lot of precision found in the faders and block-based rotary encoder. [Kristian] will be putting up the code and a few more details shortly. Hopefully there will be enough information to use different colored blocks in the step sequencer part of the build for different notes.

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Never Lose Your Pencil With OSkAR on Patrol


[Courtney] has been hard at work on OSkAR, an OpenCV based speaking robot. OSkAR is [Courney's] capstone project (pdf link) at Shepherd University in West Virginia, USA. The goal is for OSkAR to be an assistive robot. OSkAR will navigate a typical home environment, reporting objects it finds through speech synthesis software.

To accomplish this, [Courtney]  started with a Beagle Bone Black and a Logitech C920 webcam. The robot’s body was built using LEGO Mindstorms NXT parts. This means that when not operating autonomously, OSkAR can be controlled via Bluetooth from an Android phone. On the software side, [Courtney] began with the stock Angstrom Linux distribution for the BBB. After running into video problems, she switched her desktop environment to Xfce.  OpenCV provides the machine vision system. [Courtney] created models for several objects for OSkAR to recognize.

Right now, OSkAR’s life consists of wandering around the room looking for pencils and door frames. When a pencil or door is found, OSkAR announces the object, and whether it is to his left or his right. It may sound like a rather boring life for a robot, but the semester isn’t over yet. [Courtney] is still hard at work creating more object models, which will expand OSkAR’s interests into new areas.

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Hackaday Links: March 9, 2014


Thinking about starting a CNC machine, 3D printer, or laser cutter project? Misumi has you covered. They’re offering up $150 worth of free stuff with a coupon code. [CharlieX] is putting together a BuildLog laser cutter, a whole bunch of people on reddit are building 3D printers, and I have most of the rods for an i3 build. Just use the promotion code First150 on your order. Actually, read the terms and conditions, but rest assured – this is legit.

A few months ago, we saw this Enigma cypher machine that combines the classic late-30s aesthetic of the original with modern hardware – including a few 16-segment displays. Now there’s a Kickstarter for the Open Source Enigma replica, and it looks like it’s going to end up being pretty popular. Here’s the site with all the deets. Check out that QWERTZ keyboard.

[Jason] has a love of LEGO and a terrible keyboard. Combine the two and he came up with a functional LEGO keyboard. The electronics are, sadly, an old PS/2 membrane keyboard, but the mechanicals are a work of art – all the keys are mounted on a grid of Technic parts that can be positioned over each of the membrane buttons.

Want a really cool look for your next enclosure? How about LED pipes? They’re those clear plastic bits that direct the light from LEDs around corners and can make any enclosure looks like a Star Trek set piece. You can cut these things with a laser cutter like the Alima team did with their indoor air quality meter. Looks pretty cool.

BRAIGO – A Lego Braille Printer


Accessibility devices tend to be prohibitively expensive, and it’s always nice to see a hacker apply their skills to making these devices more affordable. BRAIGO is a low cost braille printer by [Shubham Banerjee]. He built the printer using parts from the LEGO Mindstorms EV3 kit, with a few additions. This LEGO kit retails for $349, and a standard braille printer costs over $2000.

The BRAIGO print head uses weights and a pin to punch holes in standard calculator paper rolls. LEGO motors are used to feed the paper and align the head for accurate printing. It takes about 5 to 7 seconds to print each letter, which are entered on the Mindstorms controller.

While this is a great prototype, [Shubham] intends to continue development with the goal of creating an affordable braille printer. He’s a bit swamped with media requests right now, but is working on releasing BRAIGO as an open source project so others can contribute. It’s an impressive project, especially for a 12 year old student. After the break, watch the BRAIGO do some printing.

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