An Arduino Programmable Load

February 24, 2014 by Brian Benchoff 31 Comments

Having a big block of hot to dump current into is a very useful thing to have if you’re testing batteries, power supplies, high power LEDs, electroplating, or any thing else that would normally require a huge resistor. [Jakub] found himself in need of an electronic load, and instead of a transistor and a pot, decided to make something more automatic: a programmable load built around an Arduino shield.

The idea behind this load is pretty simple: connect a device to a FET and shunt resistor to measure current. Drive the gate of the FET with an op-amp that maintains either constant current or constant voltage. Control everything with a DAC, and you have a programmable load controlled by an Arduino.

With such a small form factor, getting rid of all that heat was bound to be a problem. For this, [Jakub] is using a 50×50 mm BGA style heat sink with a 5V fan. If it’s good enough for a big CPU, it should be able to handle dumping 70 Watts into a FET. There’s also a conservative application of thermal paste and a very small thermistor underneath the FET that’s able to be read by the Arduino. It might slowly heat up your room, but it’s not going to catch fire.

With the Arduino sketches [Jakub] wrote for his load he was able to characterize a pair of Idea batteries and figure out how much charge a three-year-old recyclable battery had. It’s a great piece of work, and if [Jakub] is willing to go through the hassle of a Kickstarter, it would make a fine crowdfunded product.

Arduino Gets Fowl With Flappy Bit

February 18, 2014 by Adam Fabio 7 Comments

flappy-bit

We have to swallow our pride and hand it to [Dan200]. He may have finally found an application that everyone can agree is a perfect fit for Arduino. Flappy Bit is [Dan’s] Arduino Uno based Flappy Bird clone. [Dan] is a software guy at heart, but he’s taken a peck at electronics of late. Flappy Bit was just a fun side project for him to learn how to program the Arduino. The hardware consists of an 8×8 LED matrix, current limiting resistors, and a single button.

[Dan’s] implementation isn’t 100% faithful to the iOS/Android original. Rather than simply parrot Flappy Bird, he changed it up a bit. The user presses and holds the button to climb, and releases it to descend. This seems to make the game a bit more forgiving. We also won’t be missing all the lovely sound effects from Flappy Bird. While there is less flapping in Flappy Bit, it does make us more nostalgic for those tabletop LCD/LED games we played in the 80’s and can’t stop crowing about today.

[Dan] has released the full source code to the project (Pastebin link), and there is more information available on his reddit thread. Give flappy bit a try. You won’t egret it!

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STM32 Nucleo, The Mbed-Enabled, Arduino-Compatable Board

February 18, 2014 by Brian Benchoff 76 Comments

The STM32 line of microcontrollers – usually seen in the form of an ST Discovery dev board – are amazingly powerful and very popular micros seen in projects with some very hefty processing and memory requirements. Now, ST has released a great way to try out the STM32 line with the Nucleo board.

There are two really great features about these new Nucleo boards. First, they’re mbed compatable, making them a great way to get started in the ARM development world. Secondly, they have Arduino pin headers right on the board, giving you access to all your shields right out of the box.

Right now, there are four varieties of the Nucleo board based on the STM32F030, -F103, -F152, and -F401 microcontrollers. The STM32F401 is the high-powered variant, An ARM Cortex-M4 microcontroller running at 84 MHz, 512kB of Flash, and enough I/O for just about any project.

If you’d like to get your hands on one of the STM32 Nucleo boards, you can order a voucher to pick one up at Embedded World in Germany next week. Otherwise, you’re stuck ordering from Mouser or Farnell. Bonus: the high-end F401-based board is only $10 USD.

Make Your Own Smart Watch

February 17, 2014 by Nick Conn 21 Comments

Wearables are all the rage lately. Have you been eyeing the Pebble or one of the new smart watches lately but are not sure if it’s for you? With [GodsTale’s] “Retro Watch” you can now build your own, allowing you to try out a smart watch without making a huge investment.

This smart watch uses very common and easy to obtain parts: Arduino Pro Mini, HC-06 Bluetooth module, Adafruit’s 0.96’’ OLED display, and a lithium battery. It is amazing how few parts can be used to make such a functional project. While the example packaging shown is a bit rugged around the edges, it gets the job done. Having such simple hardware allows [GodsTale] to focus on the software. One of the coolest aspects of this project is the Android app [GodsTale] provides. The app provides basic functionality, such as viewing RSS feeds and Android notifications. Check out the GitHub and a more detailed write-up for more information.

It would be great to see this project evolve in the future, it has so much potential. We would love to see a custom circuit board, or a model for a 3D printed case for this awesome smart watch. See a video of the Retro Watch in action after the break. If you thought this was cool, check out a few of these recent hacks.

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Nrf24l01+ Using 3 ATtiny85 Pins

February 16, 2014 by Abe Connelly 15 Comments

[Ralph] wasn’t satisfied with the required 5 control pins to drive his nrf24l01+ transceiver module, so he used this circuit needing just 3 pin using an ATtiny85.

One of the key components was to effectively drive the chip select (CSN) line from the clock (SCK) line. The nrf24l01+ needs the CSN line to transition from high to low on the beginning of a communication. [Ralph] put the SCK line behind a diode, put a capacitor in parallel with the CSN line and altered the arduino-nrf24l01 library to encode extra delays for the clock line. This allowed the CSN line to be driven by the SCK line. Subsequent line transitions during transmission happen too fast to charge the capacitor, leaving the CSN line in a low state.

After tying the chip enable line high and dropping the 5V power line to 1.9-3.6V across a red LED, [Ralph] had an ATtiny85 controlling a nrf24l01+ module.

Though deceptively simple, a very cool hack that opens up a couple more lines on the ATtiny85.

Generating Embroidery With An Arduino

February 15, 2014 by Eric Evenchick 8 Comments

Want a nifty way to combine the craft of embroidery with electronics? The folks working on the open source Embroidermodder demoed their software by generating an embroidery of the KDE logo using a TFT screen and an Arduino.

Embroidermodder is an open source tool for generating embroidery patterns. It generates a pattern and a preview rendering of what the embroidery will look like when complete. It’s a cross-platform desktop application with a GUI, but the libembroidery library does the hard work in the background. This library was ported to Arduino to pull off the hack.

While generating pictures of embroidery with an Arduino might look neat, it isn’t too useful. However, since the library has been ported it is possible to use it to control other hardware. With the right hardware, this could be the beginning of an open source embroidery machine.

After the break, check out a video of the pattern being generated.

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An Android Controlled Arduino Drone

February 14, 2014 by Nick Conn 18 Comments

Drone

Who among us has not wanted to create their own drone? [Stefan] wrote in to tell us about a project for high school students, where a Styrofoam glider (translated) is converted into an Android (or PC) controlled drone.

[Stefan] tells us that the inspiration for this project comes from 100 years ago, when “steam-engines were THE thing” and children became introduced to modern technology with toy engines. “Today, mechatronic designs are all around us and this is an attempt to build the equivalent of the toy steam engine.” This project showcases how modern tools make it easy for kids to get involved and excited about hardware hacking, electronics, and software.

At the heart of the glider is an Arduino Pro Mini which communicates with either a computer or an Android phone via Bluetooth. It is especially interesting to note that the student’s used Processing to create the Android app, rather than complicating things by using Eclipse and Android Development Tools (ADT). While the more detailed PDF documentation at the end of the project page is in German, all of the Processingand Arduino code needed to build the project is provided. It would be awesome to see more Bluetooth related projects include a simple Android application; after all, many of us carry computers in our pockets these days, so we might as well put them to good use!

Do you have any well documented projects that introduce young and budding engineers to hardware or software hacking? Let us know in the comment section or send us a tip!