[Alex] needed a project for his microcomputer circuits class. He wanted something that would challenge him on both the electronics side of things, as well as the programming side. He ended up designing an 8 by 16 grid of LED’s that was turned into a game of Tetris.

He arranged all 128 LED’s into the grid on a piece of perfboard. All of the anodes were bent over and connected together into rows of 8 LED’s. The cathodes were bent perpendicularly and forms columns of 16 LED’s. This way, if power is applied to one row and a single column is grounded, one LED will light up at the intersection. This method only works reliably to light up a single LED at a time. With that in mind, [Alex] needed to have a very high “refresh rate” for his display. He only ever lights up one LED at a time, but he scans through the 128 LED’s so fast that persistence of vision prevents you from noticing. To the human eye, it looks like multiple LED’s are lit up simultaneously.

[Alex] planned to use an Arduino to control this display, but it doesn’t have enough outputs on its own to control all of those lights. He ended up using multiple 74138 decoder/multiplexer IC’s to control the LED’s. Since the columns have inverted outputs, he couldn’t just hook them straight up to the LED’s. Instead he had to run the signals through a set of PNP transistors to flip the logic. This setup allowed [Alex] to control all 128 LED’s with just seven bits, but it was too slow for him.

His solution was to control the multiplexers with counter IC’s. The Arduino can just increment the counter up to the appropriate LED. The Arduino then controls the state of the LED using the active high enable line from the column multiplexer chip.

[Alex] wanted more than just a static image to show off on his new display, so he programmed in a version of Tetris. The controller is just a piece of perfboard with four push buttons. He had to work out all of the programming to ensure the game ran smoothly while properly updating the screen and simultaneously reading the controller for new input. All of this ran on the Arduino.

Can’t get enough Tetris hacks? Try these on for size.

When life gives you lemons, you make lemonade. When life gives you freezing cold temperatures and a yard full of snow, you make binary clocks out of ice. At least that’s what [Dennis] does, anyway.

[Dennis’] clock is made from several cylindrical blocks of ice stacked on top of one another. There are six columns of ice blocks. The blocks were made by pouring water into empty margarine containers and freezing them. Once they were frozen, [Dennis] bore a 5/16″ hole into the bottom of each block to house an LED. Wires ran from the LEDs back into the drainage port of a cooler.

The cooler housed the main electronics. The LED controller board is of [Dennis’] own design. It contains six TLC59282 chips allowing for control of up to 96 LEDs. Each chip has its output lines running to two RJ45 connectors. [Dennis] couldn’t just use one because one of the eight wires in the connector was used as a common power line. The main CPU is an Arduino. It’s hooked up to a DS3234 Real Time Clock in order to keep accurate time. The oscillator monitors temperature in order to keep accurate time even in the dead of winter.

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7 different shades of RGB LED.. Enjoy watching it..

In Insert Coin, we look at an exciting new tech project that requires funding before it can hit production. If you'd like to pitch a project, please send us a tip with "Insert Coin" as the subject line.

It's been said that imitation is the sincerest form of flattery. Improving on a good idea, however, is truly the ultimate homage, according to the makers of the new Pinoccio microcontroller. Inspired by the Arduino, the brain trust behind the Pinoccio decided to take the stuff they liked about the popular platform -- ease of programming and low cost -- and add some features to make it even better. These include a rechargeable battery, a temperature sensor and a built-in radio that allows one Pinoccio with a WiFi shield to communicate wirelessly with other Pinoccios. The microcontroller also delivers performance that stacks up well with an Arduino Mega but at a smaller size -- the Pinoccio only measures a couple of inches long and an inch wide. The project is currently trying to raise $60,000 at Indiegogo, with supporters netting the standard Pinoccio by pledging $49 and a microcontroller with a WiFi shield for $99. For more details, feel free to check out the video after the break or peruse the project's Indiegogo page by clicking at the source link.

Previous project update: The Lomography Smartphone Film Scanner was apparently ready for its closeup. The Kickstarter project more than tripled its $50,000 goal with two more weeks to go.

Filed under: Misc

Comments

Source: Indiegogo

This is one of my 1st Arduino projects. Along with Arduino, I've used a seven segmeent led display and a piezzo buzzer. First, it beeps to indicate start. Then, counts down from 9 to 0, beeps three times. Finally, it beeps for the last time but this time the beep lasts longer.