BlueMatrix: An Arduino-based LED matrix display

Designed by Dentella Luca, BlueMatrix can be controlled remotely via a PC, smartphone or tablet.

Key project components include:

• An Atmel-based Arduino Uno (ATmega328 MCU)
• 
LED matrix display based on the HC1632C controller
• 
Lipo Rider
• 
Lipo Fuel Gauge
• 
HC-05 Bluetooth module
• 5mm plexiglas enclosure

The modules are connected as follows:

“The Arduino Uno is the heart of the project, [as] it manages the display, checks the battery status and talks (using a simple protocol) with the controlling device (Windows application or Android app),” Luca explained in a recent blog post.

“The BlueMatrix is powered by a Li-po battery (1 cell). The battery’s state of charge is monitored by Lipo Fuel Gauge, which sends the actual SoC (State of Charge) value to Arduino via I2C bus. The Lipo Rider module rises the battery voltage to 5V to power all the other modules and allows it to recharge the battery using a simple, mini-USB power supply.”

Meanwhile, the HC-05 module is tasked with managing Bluetooth connectivity.

“After having established the connection with the remote device, it transparently transport the data received/transmitted by Arduino via serial connection,” said Luca.

On the software side, Luca developed two applications to control BlueMatrix: a .Net application (developed in C#) and an Android app.

“BlueMatrix was designed to be portable, therefore I suppose that it will be mostly controlled using a smartphone; this is the reason why the Android app is better designed than the desktop one and it’s also available on Google’s Play Store,” he added.

Interested in learning more? You can check out the official BlueMatrix project page here and download the Arduino sketch on GitHub here.

IViny is an ATtiny85-powered DAQ

The Ivmech crew was recently in need of a small, inexpensive device capable of sensing analog values and toggling a few digital pins – all while logging everything to a PC.

Ultimately, the team decided to build the IViny DAQ, a mini data acquisition device powered by Atmel’s ATtiny85 microcontroller (MCU).

Aside from Atmel’s versatile ATtiny85 MCU, key project components include:

• 2 channels 0 – 5V ve 0 – 3V digital input/output
• 2 channels 0 – 5V 10 bit analog input
• Channel maximum current 20 mA
• USB power supply
• V-USB based comms
• PC user interface (UI)
• 150 S/s (set to increase with future firmware upgrades)
• 50 mm x 33 mm x 17 mm

“The IViny features two digital channels and two 10 bit analog channels, just like you’d find in any ATtiny85 project,” writes HackADay’s Brian Benchoff.

“Power is supplied over USB, and a connection to a computer is provided by V-USB. There’s also a pretty cool Python app that goes along with the project able to plot the analog inputs and control the digital I/O on the device.”

As Benchoff notes, the device doesn’t exactly run at light speed, with the firmware currently supporting 100 samples per second.

“[However], an upcoming firmware upgrade will improve that. Still, if you ever need to read some analog values or toggle a few pins on the cheap, it’s a nice little USB Swiss army knife to have,” he adds.

Interested in learning more about IViny, the ATtiny85-powered DAQ? You can check out the project’s GitHub page here.

ATmega328 external serial monitoring – sans PC

Serial monitors are typically used to help Makers and engineers more easily debug their projects.

However, as HackADay’s Will Sweatman notes, traditional serial monitors require a PC or laptop loaded with a terminal program.

“Most of the time this is not an issue, because the PC is used to compile the code and program the project at hand,” Sweatman explained.

“But what if you’re in the field, with a mission of fixing a headless system and in need a serial monitor? Why lug around your PC when you can make your own external serial monitor?”

And that is precisely why ARPix designed a barebones, albeit fully functional serial monitor around Atmel’s versatile ATmega328 microcontroller (MCU) and a 102 x 64 LCD display.

Although the minimalistic platform lacks a keyboard port like some other external monitors, tact switches facilitate access to the user interface (UI) for start and stop commands. As expected, the tact switches can also be used to set the baud rate.

Interested in learning more? You can check out the project’s official Instructables page here, which offers the relevant sketches and parts list.

Activating a PC with a knock and an ATtiny

A Maker by the name of Joonas has designed a knock sensor to activate his PC. According to the HackADay crew, the entire project cost Joonas a grand total of $10 and is built around Atmel’s ATtiny45 MCU which is tasked with emulating a PS/2 device.

“This takes advantage of his computer’s ability to boot upon receiving PS/2 input,” HackADay’s John Marsh explained. “The build uses a Piezo buzzer and a 1M Ohm resistor as a knock sensor exactly as the official Arduino tutorial demonstrates, [plus] one of those PS/2-to-USB adapters that are most likely lurking in the back corner of every drawer in your office.”

In addition, says Marsh, AVRweb was used to disable the 8X clock divider so there would be sufficient clock cycles for PS/2 communication. Joonas subsequently loaded some test code (final version posted to Github) to ensure the vibrations were being detected correctly.

Readers of Bits & Pieces may also want to check out a recent article about a Halloween Knock Box powered by Atmel’s versatile ATtiny45 (or 85) microcontroller (MCU).

The box is fairly easy to put together, as basic components include an MCU, a piezo element (amplifier) for the knock sensor and a motor to provide the knocking feedback.

A closer look at Atmel’s Xplained Pro kits

Atmel’s comprehensive lineup of Xplained Pro boards offers engineers everything they need to start designing microcontroller (MCU) applications in minutes. First off, the boards are quite easy to connect, linking to PCs with just a USB cable.

As expected, the boards are automatically recognized by Atmel Studio, facilitating direct access to example projects and documentation. Meanwhile, hardware extension boards provide easy access to all functionality of the MCU.

Currently, Xplained Pro kits are grouped into three primary categories:

• Evaluation kits – Lowest cost kits starting at $39 for evaluating MCUs and developing with example projects in Atmel Studio.
• Starter kits – Low-cost bundle of MCU and extension boards starting at $99 for rapid application prototyping and development with Atmel Studio and Atmel Software Framework.
• Extension kits – Boards with additional functionality, connecting to Xplained Pro MCU boards through standardized connectors.

On the evaluation side, Atmel offers the SAM D20 Xplained Pro, SAM4N Xplained Pro, SAM4S Xplained Pro, SAM4L Xplained Pro and the ATmega256RFR2 Xplained Pro.

In terms of extension boards, there is the I/O1 Xplained Pro, OLED1 Xplained Pro, SLCD1 Xplained Pro and the PROTO1 Xplained Pro.

Interested in learning more? Be sure to stay tuned, because next time we’ll be getting up close and personal with Atmel’s MCU Xplained (evaluation) kits.