Hack All The Things In The Time You Save With This LED Pomodoro Timer

February 9, 2014 by 36 Comments

Do you want to use your time more productively but are tomato-averse? [Robin]’s LED Pomodoro timer could be the perfect hack for you.

The Pomodoro Technique is a time management solution developed in the late 1980s. The basic idea is to spend a very focused 25 minutes performing some activity such as working or studying and then take a 5-minute break. Many of its proponents use a tomato-shaped kitchen timer to alert them to switch between the two states, but [Robin] wanted to make his own and learn along the way.

First, he wanted to use an ATtiny85 and learn about its features. Specifically, he used its timers, PWM, and low-power sleep mode. [Robin] used Charlieplexing to drive a total of six LEDs. When the timer starts, five yellow LEDs are driven high to indicate each 5-minute slice of work time. A red LED is lit during the 5-minute break.

[Robin] also explored compact PCB design and fabrication. All components are SMD and his board is 4cm square. [Robin] is using this SMD buzzer for discrete feedback. He included a footprint for a six-pin ISP header and programmed it with pogo pins. The timer is completely interrupt-driven: one click of the tactile button starts the work counter, and the buzzer sounds when time is up. A second click starts the break counter.

[Robin] has made everything available in his GitHub repo and encourages you to use it. Time’s a-wastin’!

Mario Doorbell Guaranteed To Drive A-You A-Crazy

February 9, 2014 by 8 Comments

marioDoorbell

Is your doorbell not exciting enough for your guests? [Joe] wanted to provide a little entertainment for his visitors, so he redesigned his doorbell with a Mario theme.

Whenever someone presses the button—which carries the Mario coin image—the segment display increments and the Mario coin sound plays. To add variety, the life-up sound plays at every 10 coins and the mushroom upgrade sound plays upon reaching 100. [Joe] tried putting the life-up sound at its appropriate 100’s place and the mushroom sound at every 10, but he decided the brevity of life-up was more tolerable in the 10’s slot.

The project was divided into two components. The door button has a PIC16F628A microcontroller with a dual 7-segment LED display, a button, and a homemade circuit board. All this lives in a simple box covered by a Yoshi’s Island-themed decal. The button’s board connects to a separate ringer board—based around a PIC16F87—with a MCP4822 DAC and a 25LC1024 EEPROM. Button presses on the first board prompt a request for a sound clip read on the EEPROM. Keep clicking for a demo video below.

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Driving RGB Pixel LEDs With CAT5 Cable

February 9, 2014 by 20 Comments

cable-test

[Teknynja] was working on a project where he needed to drive a few strips of Adafruit Neopixels – WS2812 LED strips – that were located several feet apart. These LED strips draw a lot of current, and are very timing sensitive; anything more than a few feet of wire between the microcontroller and the LED strip will probably result in missed data, voltage drops, dimming LEDs, and possibly a non-functional strip.

The solution, as in all matters concerning long distance transmission of data, was CAT5 cable. [Teknynja] used RS-422 drivers and receivers to pull this task off, with 75174 line drivers receiving signals from a Teensy 3.0, and 75176 bus transceivers reading everything at the other end of a 20 foot cable.

For the power drop issue, [Teknynja] is feeding 12V into a few of the wire pairs in the cable and using a cheap  LM2596 buck converter to step everything down to 5V at the strip.

With a fairly simple circuit, [Teknynja] was able to drive a few strips of WS2812 LEDs through 20-foot lengths of CAT5 cable with ease; it worked just the same as if the pixels were connected directly to the Teensy on a workbench.

Using A Computer To Read Braille

February 9, 2014 by 6 Comments

braille

[Matthiew] needed to create a system that would allow a computer to read braille. An electromechanical system would be annoying to develop and would require many hardware iterations as the system [Matthew] is developing evolves. Instead, he came up with a much better solution using a webcam and OpenCV that still gets 100% accuracy.

Instead of using a camera to look for raised or lowered pins in this mechanical braille display, [Matthiew] is using OpenCV to detect the shadows. This requires calibrating the camera to the correct angle, or in OpenCV terms, pose.

After looking at the OpenCV tutorials, [Matthiew] found a demo that undistorts an image of a chess board. Using this same technique, he used fiducials from the ARTag project to correctly calibrate an image of his mechanical braille pins.

As for why [Matthiew] went through all the trouble to get a computer to read braille – something that doesn’t make a whole lot of sense if you think about it – he’s building a braille eBook reader, something that just screams awesome mechanical design. We’d be interested in seeing some more info on that project as well.

Upgrading Home Automation To Home Anticipation

February 9, 2014 by 9 Comments

geofencingHomeAnticipation

[Bithead’s] already built some home automation to control the lighting and temperature in his house while he’s away, but he wanted to take things a step further and have the house automatically anticipate his arrival and adjust the environment accordingly. The project takes advantage of geofencing to create a perimeter around the home that listens for a transceiver in [Bithead’s] car. We featured a similar project with a Raspi a few months ago, which locked the doors upon driving away.

[Bithead’s] implementation uses a pair of Digi Xbee Pro XSC radios with U.FL antennas to provide an impressive 2+ mile range of communication. The home-based Xbee hooks up to a Parallax Xbee USB adapter and subsequently into his computer—its antenna sits in a nearby window on the top floor of his house to maximize range. For his car, [Bithead] originally opted for an Xbee shield and an Arduino Uno, but he’s recently overhauled the build in favor of an Arduino Fio, which reduced the footprint and increased the range. Check out his page for the build log specifics and more pictures.

Adding An RPM Readout For A Home Made CNC Mill

February 8, 2014 by 5 Comments

rpm_lcd

[Rui] recently put the finishing touches on his homemade CNC mill, which utilizes a dremel-like rotary tool. The problem with using rotary tools for this kind of application is you don’t really have an accurate speed readout… so he designed his own RPM gauge.

The sensor is in itself very simple. He’s using a TLE4935L hall effect sensor, a spare 16FE88 microcontroller, a Nokia LCD, and one tiny neodymium magnet. The magnet has been carefully epoxied onto the motor fan, with the hall effect sensor close by. He’s also built a guard around it, just in case the magnet decides to fly off at high speeds.

During testing he hooked up the hall effect sensor to both his home-made circuit, and an oscilloscope to confirm his findings. Once he was assured everything was working properly he sealed it off and mounted the LCD above the spindle as a nice digital readout.

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Pneumatic Powered Flight Simulator

February 8, 2014 by 16 Comments

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Remember that feature a few days ago about the Cessna 172 flight simulator? It was pretty awesome. But do you know what it was missing? It was missing this. A fully motion-controlled, pneumatically driven, flight simulator cockpit.

[Dominick Lee] is a high school senior, and he was able to whip together this awesome flight simulator made out of PVC pipe, pneumatic cylinders, an Arduino, a projector, and a gaming PC — in just a few months time! He calls it the LifeBeam Flight Simulator, and he’s released all the information required to make one yourself.

It’s most similar to a Stewart platform simulator, which features 2 degrees of freedom, but instead of 6 actuators, this one runs on only two pneumatic cylinders. It works by exporting the roll and pitch (X and Y) data from the game, and then parsing it to an Arduino which controls the pneumatic valve amplifier, powering the cylinders.

It’s an amazing project, and it sounds like [Dominick] had an awesome physics professor, [Dr. Bert Pinsky], to help mentor him. Don’t forget to check out the demonstration video!

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