A Business Card That Plays Simon Says

January 10, 2014 by Kevin Darrah 16 Comments

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When your name is Simon and you want to build your own circuit board business card, it makes perfect sense to incorporate a game of Simon Says, and that’s exactly what [Simon] did with his Business Card.

You may see a resemblance to the Engineer’s Emergency Business Card; that’s because [Simon] took inspiration from that card to build his own. The game of Simon Says is played via 4 low-profile pushbuttons and 4 0805 LEDs. The microcontroller of choice to run the game is an ATtiny45 set up to work with the Arduino IDE. But with only 5 pins available for I/O, [Simon] had to give up 4 pins to the LEDs and configure the remaining pin as an analog input. The buttons are tied into a voltage divider that feeds the analog input, so depending which button is pressed, a different voltage is read in, thus a value from 0 to 1023 determines which button was pressed.

One of the great things about this write-up is that it goes through the process of etching PCBs at home using the toner-transfer method. We’re not sure how many home-etched business cards he’s willing to pass out, but surely whoever does get the card, will never forget his name.

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Christmas Tweetball

January 9, 2014 by James Hobson 4 Comments

The holidays are long over, but we’re still getting a smattering of holiday themed hacks. For this one, the [Han’s] family decided to make a Christmas bauble that relays their tweets to them!

They call it the Tweetbal which is Dutch for — well — Tweetball! Whenever someone tweets with the hashtag #tweetbal it gets displayed on the 20×4 serial LCD display. They’re using an Arduino Uno with an RN-XV WiFly module to receive and send the tweets to the display. A large white plastic ornament ball houses it all secured very firmly with our favorite adhesion method — duct tape. It’s a pretty simple project, but a great holiday hack if we do say so ourselves — plus it could be easily used for non-holiday purposes — like a desktop trinket twitter feed!

Stick around after the break to see its tweeting capabilities in action.

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Arduino Ball Throwing Game

January 9, 2014 by Kevin Darrah 8 Comments

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Building your own gaming platform is pretty cool on its own, but when the game actually looks like fun to play, well that’s on a different level of cool. [Zippy314] designed an Arduino based game platform as a Christmas present to his son called the Das Blinken Bonken!

Like all highly addicting games, the gameplay is simple; the player throws a ball at the target board while aiming to hit a specific ‘pad’. As shown in the video after the break, there are many game possibilities with this platform, like trying to hit the illuminated target each time, or just trying to hit all of the pads on the board as fast as possible.

A pad is registered as a ‘hit’ with the help of home-made pressure sensors, which are each constructed in a ‘sandwich’ of pressure-sensitive conductive sheets. This is the same material used in these LED Sneakers. Since the resistance through the sheet lowers as pressure is applied, a simple voltage divider circuit is used to feed the analog inputs on the Arduino, thus making it very easy to detect a ‘hit’. An I2C 4-Digit 7 Segment display keeps score and displays the game title, while a strip of addressable RGB LEDs give player feedback and other vital gameplay information.

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Self-Balancing Robots Wobble, But They Don’t Fall Down

January 9, 2014 by Kristina Panos 7 Comments

[Trandi] can check ‘build a self-balancing robot’ off of his to-do list. Over a couple of weekends, he built said robot, and, in his own words, managed not to over-design it. It even kept the attention of his 2-year-old son for several minutes, and that’s always a plus.

He was originally going to re-purpose one of his son’s RC cars, but didn’t want to risk breaking it. Instead, he designed a triangular 3-D printed chassis to hold a motor and some cogs to fit both the motor shaft and some re-used Meccano wheels. [Trandi]’s design employs an MPU 6050 6-DOF IMU for the balancing act and is built on an Arduino Nano clone.

[Trandi] is controlling the motor with an L293D, which has built-in flyback diodes to minimize spikes. He found that the Nano clone was not powerful enough to handle everything, so he added an L7805CV voltage regulator. After the break, watch [Trandi]’s cute bot tool around on various types of terrain, with and without a payload.

Don’t have an IMU lying around? You don’t really need one to build a self-balancing bot, as this IR-based lilliputian bot will demonstrate.

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A Transparent 7-Segment Display

January 9, 2014 by Marsh 40 Comments

Though [Connor] labels it as a work in progress, we’re pretty impressed with how polished his transparent 7-segment display looks. It’s also deceptively simple.

The build uses a stack of seven different acrylic panes, one in front of the other, each with a different segment engraved onto its face. The assembly of panes sits on a small mount which is placed over seven rows of LEDs, with 5 LEDs per row. [Connor] left an air gap between each of the seven individual acrylic panes to clearly distinguish which was lit and to match the separation of the LED rows. To display a number, he simply illuminates the appropriate LED rows, which scatter light across the engraved part without spilling over into another pane.

You can find a brief overview and some schematics on [Connor’s] website, and stick around for the video demonstration below. We’ve featured [Connor’s] work before; if you missed his LCD data transfer hack you should check it out!

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Ride, Captain, Ride Aboard Your Arduino-Controlled Autopiloted Sailboat

January 8, 2014 by Kristina Panos 22 Comments

[Jack], a mechanical engineer, loom builder, and avid sailor wanted an autopilot system for his 1983 Robert Perry Nordic 40 sailboat with more modern capabilities than the one it came with. He knew a PC-based solution would work, but it was a bit out of reach. Once his son showed him an Arduino, though, he was on his way. He sallied forth and built this Arduino-based autopilot system for his sloop, the Wile E. Coyote.

He’s using two Arduino Megas. One is solely for the GPS, and the other controls everything else. [Jack]’s autopilot has three modes. In the one he calls knob steering, a potentiometer drives the existing hydraulic pump, which he controls with a Polulu Qik serial DC motor controller. In compass steering mode, a Pololu IMU locks in the heading to steer (HTS). GPS mode uses a predetermined waypoint, and sets the course to steer (CTS) to the same bearing as the waypoint.

[Jack]’s system also uses cross track error (XTE) correction to calculate a new HTS when necessary. He has fantastic documentation and several Fritzing and Arduino files available on Dropbox.

Autopilot sailboat rigs must be all the rage right now. We just saw a different one back in November.

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Controlling Cheap, Awesome Christmas Lights

January 7, 2014 by Brian Benchoff 13 Comments

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[James] was wandering around Walgreens after Christmas and found something very interesting – RGB LED Christmas lights that were individually addressable. At $6.50 for a strand of 15 lights, he just had to buy a few and figure out the control protocol. After all, who can turn down a big, cheap, controllable RGB LED strip?

The packaging for these lights – apparently manufactured by BriteStar – includes a ‘try me’ button that cycles through different light patterns. This button is what initially tipped [James] off to the fact the lights on this strand could be individually controllable. Opening up one of the lights, he found exactly what he wanted: an epoxy blob, two wires for power, and three wires for the signaling.

After checking out this light with a scope and logic analyzer, [James] realized there was a very, very simple protocol going on. Essentially, the entire string functioned as a gigantic shift register, taking the values for one light and pushing it down the string. In looking at the protocol, [James] also discovered] these lights support 16 levels of brightness. Yep, RGB LED Christmas Lights with PWM for under $7. Can’t beat that.

[James] wrote an Arduino library to control these strings and put it up on Github. While your local Walgreens has probably already hidden these lights away in the back of the store, it might be worth asking around to see if they have any left.