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11 Jul 2014


Pup05 shared his SmartMatrix project. He writes:

The panel fits perfectly, just had to shim it with a little bit of folded card stock on each side. There’s plenty of room for the Teensy and SmartMatrix board, wiring, SD card, etc. I cut out a piece of white printer paper to size, and placed it between the panel and the glass for a bit of diffusion. The magnetic feet that came with my panel from Adafruit fit perfectly, and keep the panel pushed against the paper and glass. I cut a notch in the bottom of the back, just big enough for the power cord, USB cable, and IR receiver.
I loaded up Craig’s LightAppliance sketch and made a few minor modifications, loaded up my SD card with the animated GIFs I wanted, and everything works great. Unfortunately, I already had my Teensy soldered on to the SmartMatrix board, and didn’t feel like pulling it off to solder the RTC crystal on to the back. I might do that later, and add the temperature sensor.

SmartMatrix project - [Link]

8 Jul 2014


ElecFreaks @ elecfreaks.com writes:

We were just wondering in the current market where capacitive touch screens, resistive touch screens, TFT displays are flooding, DIY enthusiasts have been rarely used dot matrix screens. Here we use 5mm 8 * 8 dot matrix screen and phototransistor to achieve a pen write function. Sounds fun? But how to specifically make it? Can we achieve a larger area pen write?

Dot Matrix Pen Write Screen - [Link]

8 Jun 2014


jollifactory @ instructables.com writes:

One of the electronics DIY kit jolliFactory came up with is the Bi-color LED Matrix Driver Module Kit. This module is designed to be chain-able so that you may daisy-chain the modules together to the number of modules you need to suit your project.

Arduino Tetris on bi-color LED matrix - [Link]

4 Jun 2014


by praveen @ circuitstoday.com:

Digital code lock or digital combination lock are a type of digital locks where a combination of digits/characters or both are used for unlocking the lock. This article is about a simple digital code lock using arduino. Here the code consists of a combination of digits from 1 to 6. There are separate keys for locking and unlocking the system. The system can be unlocked by pressing the unlock button after entering the correct combination of digits. A hex key pad is used as the input device. Only the first two rows of key (1, 2, 3, A, 4, 5, 6, B) are used in this project. A is used for locking the system and B is used for unlocking the system. Read this article Interfacing hex keypad to arduino for knowing more about hex keypad and its interfacing to the arduino. The circuit diagram of the digital code lock using arduino is shown in the figure below.

Simple digital code lock using arduino - [Link]

28 May 2014


Interfacing hex keypad to arduino @ circuitstoday.com

This article is about how to interface a hex keypad to arduino. Hex keypad is a very important component in embedded systems and the typical applications are code locks, calculators, automation systems or simply any thing that requires a character or numeric input. This project will display the pressed key in the serial monitor window of the arduino IDE. The same project can be modified to display the pressed key on 7-segment LED display or an LCD display. Before going into the details, have a look at the hex keypad.

Interfacing hex keypad to arduino - [Link]

26 May 2014

Dice mode from LEDMatrixDice

by A study of entropy

This arduino sketch makes use of the Entropy library as a source of truly random numbers to simulate various dice (4, 6, 8, 10, 12, and 20-sided) as well as several other useful forms of random numbers. In total the device has eleven separate modes.

LED Matrix Dice - [Link]

21 May 2014

Luca Dentella has published his latest project: BlueMatrix. [via]

It’s a portable LED matrix display based on Arduino Uno, powered by a Lipo battery and connected via Bluetooth to a personal computer or an Android smartphone. I’ve also developed the controlling app for Android, available on Google’s PlayStore.

All the schematics, source files, inkscape files for the enclosure etc., are available on my blog and in my GitHub repository.

BlueMatrix – Bluetooth controlled LED matrix - [Link]

18 May 2014

KeyPadEncoderTitleRaj @ embedded-lab.com build an encoded matric keypad. He writes:

Matrix keypads are an excellent way of providing user input data into microcontroller-based systems. Keypads find applications in remote controls, standalone data-loggers, security systems, door entry systems, calculators, microwave ovens, etc. They are usually implemented as pushbutton switches arranged in a row and column matrix format to reduce the number of I/O connections. For example, a 16-switch keypad is arranged in a 4 X 4 matrix format requiring 8 I/O connections. A pressed key is detected and identified by scanning the keypad to look for a short circuit condition between a row and a column wire. The keypad scanning can be done either by polling or by means of an interrupt routine. In the polling approach, the scanning process is repeated in a continuous loop, which results in waste of CPU time. The interrupt-approach is more efficient and it notifies the processor when there is a keystroke. Another approach of interfacing a keypad to the microcontroller is by using a dedicated keypad encoder IC, which further reduces the I/O connections and makes the interface much simpler. In this project, we are building a simplified 16-switch keypad using the MM74C922 encoder chip, which converts a key switch closure to a 4-bit nibble output.

MM74C922N-based encoded matrix keypad - [Link]

12 Apr 2014


Syst3mX @ instructables writes:

One day I was sitting behind my desk at work and I got that weird need to build something, after looking around for a bit I got my eye on an LED matrix and that sparked an idea in my head : “I WANNA MAKE A TAMAGOTCHI”.

So for those of you that don’t know what the heck is a Tamagotchi here is a little snip-it from wikipedia :
“The Tamagotchi (たまごっち Tamagocchi?) is a handheld digital pet, created in Japan by Akihiro Yokoi of WiZ and Aki Maita of Bandai. It was first sold by Bandai in 1996 in Japan.”

So my take on this classic toy is to make it in to a desktop gadget with an LED matrix for a display, and an Arduino for brains to make it more accessible to people. With that said join me as we design,build and program the World’s first (As far as I know) desktop Tamagotchi.

Make a Desktop Tamagotchi - [Link]

12 Apr 2014


jollifactory @ instructables writes:

Here, we show how a 7 Bi-color 8×8 LED Matrix Scrolling Text Display is built, in which messages and commands can be sent to it via Bluetooth using an Android Smart Phone. Logically, any devices capable of sending text messages via Bluetooth may be adapted to work with the display.

To build this project, basic electronics component soldering skills and some knowledge on using the Arduino or Arduino based micro-controllers are required.

The reason for building a 7 LED Matrices long display is that it is quite adequate for ease of reading scrolling text and also because the largest tinted acrylic sheet easily available in Hobby or Art shops is 18 inches by 12 inches, which is just the right length for making the enclosure for the display as each LED matrix is around 60mm x 60mm in size.

7 Bi-color LED Matrix Scrolling Text Display - [Link]





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