More RAM with the Teensy++ 2.0

So, you’ve decided to use the Atmel-powered Teensy++ 2.0 (AT90USB1286) in your latest Maker project.

Want to know how you can access more memory? 

Well, you’re in luck, because xxxajk recently came up with a library that allows the use of significant RAM expansion with the Teensy++ 2.0.

As HackADay’s Brian Benchoff notes, xxxajk’s latest library is actually a port of XMEM2, an earlier project that added RAM expansion and multitasking to the Arduino Mega (ATmega1280). 

As expected, XMEM2 works with Rugged Circuits QuadRAM and MegaRAM expansions for the Arduino Mega as well as Andy Brown‘s 512 SRAM expansion.

“Up to 255 banks of memory are available and with the supported hardware, the Teensy can address up to 512kB of RAM,” Benchoff explained. 

”XMEM2 also features a preemptive multitasking with up to 16 tasks, the ability to pipe messages between tasks and all the fun of malloc().”

Interested in learning more? You can check out xxxajk/xmem2 on Github here, QuadRAM here, MegaRAM here and the 512 SRAM expansion here.

Towards an open source embroidery machine

The Embroidmodder crew has debuted a video showcasing the rendering of the KDE logo using a TFT screen and an Atmel-based Arduino board.

As HackADay’s Eric Evenchick notes, Embroidermodder can perhaps best be described as 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,” he explains. 

”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.”

However, the Embroidmodder crew isn’t content with simply generating patterns. Since the library has been ported, future developers can use the concept to control new hardware, which may very well lead to an open source embroidery machine.

“Instead of drawing, we could change it to control motors and other hardware to create an open source embroidery machine,” adds Embroidmodder rep Josh Varga. 

”This is what the brain of an embroidery machine looks like and it just needs a heart and body.”

Interested in learning more? You can check out the Embroidermodder’s official page here.

Video: Mega + Uno drives this 8X8X8 cube invader

Anred Zynch recently debuted a massively slick 8x8x8 LED cube — configured as a Space Invaders style game with a Playstation 1 controller.

According to Hackaday’s James Hobson, the cube is powered by an Arduino Mega (ATmega2560) which is tasked with driving the 512-LED array. 

Meanwhile, an Arduino Uno (ATmega328) is responsible for generating sound effects during gameplay.

Aside from the two Atmel based Arduino boards, key cube components include:

• 512x LEDs
• 10x Silver plated wire 0.8mm for sinkers and LED grid
• 2x Breadboard 160×100 H25PR160 (sinkers)
• 1x 100 Ohm resistor
• 1x Speaker 8 Ohm
• 2x resistor between 1,5 K and 47 K
• 1x switch 2 or 3-positions
• 1x or 2x 10K ohm resistor

Zynch’s cube — recently surfaced on Instructables — was reportedly inspired by a number of cube projects, including Chr’s and yes, the Borg cube by Das-Labour.

Interested in learning more? You can find additional information, along with a full parts breakdown on the project’s official page here.

Driving alphanumeric LCDs with three wires

Writing for HackADay, Brian Benchoff notes that the HD44780 LCD controller is currently the de-facto method of choice for adding a small text display to Maker projects.

“If you need a way to display a few variables, a few lines of text, or adding a small user interface to a project, odds are you’ll be using one of these parallel LCDs,” says Benchoff.

“These displays require at least six control lines, and if you’re using a small microcontroller (MCU) or are down to your last pins, you might want to think about controlling an LCD with a shift register.”

Indeed, a Maker by the name of Matteo recently chose the ubiquitous ’595 shift register configured as a serial to parallel converter to drive his LCD, a method which requires only three pins on an Atmel-based Arduino board. 

On the software side, Matteo modded the stock Arduino LiquidCrystal library and posted it on Gitbub.

“Most of the functions are left untouched, but for this build the LCD can only be used in its four bit mode,” Benchoff adds.

“That’s not a problem for 99% of the time, but if you need custom characters on your LCD you can always connect another shift register.”

Interested in learning more? You can check out Matteo’s official project page here.

DIY curved display with an Arduino Mega

A Maker by the name of Marin Davide has designed a DIY curved display with an Atmel-powered Arduino Mega (ATmega1280), nichrome wire and thermochromic liquid crystal ink.

According to James Hobson of HackADay, the current prototype uses a sheet of plastic coated in thermochromic ink – curved on an MDF frame.

“To display digits, Davide created tiny segments of the 7-segment display by wrapping the nichrome wire around pieces of cardboard, which then have been glued to the back of the display,” Hobson explained.

Meanwhile, Davide noted that although the prototype shows a 7-digit display, the detailed build guide can be easily modded to create a small dot-matrix display.

“The working prototype uses a sheet material printed with thermochromic liquid crystal ink,” Davide wrote in an official Design News description.

“It changes color (bright blue) when heated above 27C. Nickel-chrome wire is used to heat the segments and everything is controlled by an Arduino Mega board.”

The DIY curved display was made with 4mm Mdf, cut with a CNC, although this can also be done by hand. In addition, Davide used a 24V DC power supply, converted to 20Vdc with a KIA7820A. A 1000uF capacitor reduces noise on the 24V line, while a 220uF reduces noise on the 20V line. Last, but certainly not least, the Atmel-based Arduino is USB powered from the PC.

Interested in learning more about building a DIY curved display with an Atmel-based Arduino Mega? You can check out HackADay’s coverage here, the Design News article here and a detailed build tutorial (PDF) here.

Measuring capacitance with an Arduino Uno

Capacitance is typically defined as the ability of a body to store an electrical charge. More specifically, any object that can be electrically charged exhibits capacitance.

 A multimeter or multitester, also know as a VOM (Volt-Ohm Meter) can be used to measure the capacitance of a capacitor, but what if you don’t have one handy?

As it turns out, capacitance can be measured with an Atmel-based Arduino Uno (ATmega328) – sans external components and only ~20 lines of code. 

A blog post, written by Jonathan Nethercott that was recently featured on HackADay, explains how.

“[He] does an excellent job explaining a capacitance test circuit which uses a reference capacitor to calculate the unknown capacitance,” writes HackADay’s James Hobson. 

”He further explains that, with the Arduino Uno, you can remove the reference capacitor from the circuit, and simply use the stray capacitance present in the board and microcontroller, which can be calculated.”

Meaning, creating a test circuit is as simple as plugging in a capacitor to pins A0 and A2. On the software side, Nethercott’s code sense a 5V pulse to the capacitor – measuring the voltage on the other side, looping every half second and outputting the data onto a chart.

Nevertheless, as HackADay’s Hobson notes, the above-mentioned technique does require some calibration, with Jonathan measuring a known capacitor for a baseline and using the confirmed data to calculate the stray capacitance in the Arduino. 

Once accurately calibrated, users can typically achieve a resolution of approximately 1% for capacitors between 3.5pF and 225pF and around 5% for capacitors between 0.5pF and 1300pF.

Interested in learning more about how you can macgyver your Arduino Uno to measure capacitance? You can check out Jonathan Nethercott’s detailed blog post here.

Astrophotography tracking with Atmel’s ATtiny85

Astrophotography describes the imaging of astronomical objects along with large areas of the night sky. According to Wikipedia, the first photograph of an astronomical object (the Moon) was taken in 1840, although it was not until the late 19th century that advances in technology allowed for detailed stellar photography.

Image Credit: Wikipedia

In addition to recording the details of objects such as the Moon, Sun, and planets, astrophotography is also capable of imaging objects invisible to the human eye such as dim stars, nebulae and galaxies. This accomplished by long time exposure, as both film and digital cameras can accumulate and sum light photons over extended periods of time.

As HackADay’s John Marsh notes, the basic idea is to capture images otherwise undetectable by the human eye through longer exposures.

“Unfortunately, the big ball of rock we all inhabit has a tendency to rotate, which means you need to move the camera to keep the night sky framed up,” he explains.

Unsurprisingly, the vast majority of professional astrophotography trackers require precision parts and fabrication. However, a Maker by the name of ZigZagJoe found an alternative with Chris L. Peterson’s stalwart Cloudbait Observatory model. 

Dubbed the “Barn Door Tracker,” the platform is powered by Atmel’s ATtiny85 microcontroller (MCU) and runs a pre-configured table that determines step rate against time.

Interested in learning more about ZigZagJoe’s ATtiny85-powered astrophotography tracker? You can check out the project’s official page, along with additional pictures here.

Securing offline passwords with Atmel MCUs

Over the past few months, Bits & Pieces has featured a number of DIY offline password keepers built around Atmel microcontrollers (MCUs).

First up is the official HackADay Mooltipass. Powered by Atmel’s ATmega32U4, the device is equipped with an easily readable screen, a read-protected smart-card (AT88SC102) and flash memory to store encrypted passwords.

Next up is the USBPass. Designed by a Maker named Josh, the platform comprises an ATmega32U2 MCU, USB connector, three buttons and a few passives chips. Like the Mooltipass, the USBPass is connected to a computer via USB and read as an HID keyboard.

The latest Atmel-powered offline password keeper to surface in the Maker community and on the HackADay website? Cyberstalker’s ATMega32U4-packing Final Key, which includes a single button and LED, all neatly enclosed in a 3D printed case.

According to HackADay’s Mathieu Stephan, the Final Key is linked to the host computer via USB and recognized as a composite comm device/HID keyboard, requiring Windows-based devices to install drivers.

“AES-256 encrypted passwords are stored on the device and can only be accessed once the button has been pressed and the correct 256 bit password has been presented through the command line interface,” Stephan explained. “Credentials management and access are also [executed by] the latter.”

Interested in learning more about the ATMega32U4-powered Final Key? You can check out the project’s official page here.

Video: Diving under the sea with a DIY ROV

Doug and Kay are currently building an underwater ROV capable of diving 3,000 below the waves, maneuvering on the ocean floor and relaying video as well as side-scan sonar signals back to the surface.

As HackADay’s Brian Benchoff notes, the duo continues to document the entire build process on YouTube, with the first video depicting the construction of a pressure vessel.

“For communication with the surface everything is passing over a single Cat5 cable. They’re using an Ethernet extender that uses a twisted wire pair to bring Ethernet to the ocean bottom,” Benchoff explained.

“With that, a few IP webcams relay video up to the ship and a simple [Atmel-based] Arduino setup allows for control of the ship’s thrusters.”

In terms of the thrusters, Doug and Kay selected off the shelf brushless mortars for model RC cars and planes.

“By potting the coils of a brushless outrunner motor, Doug and Kay found this solution makes an awful lot of sense,” Benchoff continued.

“It’s cheap, fairly reliable, doesn’t require a whole lot of engineering.”

Interested in learning more about the undersea ROV project? You can check out Doug and Kay’s official blog here.

A retro modern Nixie clock with Atmel’s ATmega48

As we’ve previously discussed on Bits & Pieces, there really is nothing quite like the comforting glow of a Nixie tube. Reboots apparently couldn’t agree more, as the retro modern Nixie clock he designed clearly illustrates.

According to HackADay’s James Hobson, Reboots was inspired to build the clock after coming across an old General Electric battery charger for sale.

“The Nixie tubes he chose for the project came from a lot sale on eBay, Russian surplus IN-12 tubes. He even managed to find an English datasheet for them,” Hobson explained.

“Having decided on the Nixie tube, driver, and case, he now needed a reliable power supply. Threeneuron’s design fit the bill nicely, however it ended up being a bit noisy under load, but the TubeClock kit used a free-running transistor oscillator, which was in fact even louder under load.”

From there, said Hobson, it was a matter of testing the tubes, prototyping PCBs and programming Atmel’s stalwart ATmega48 microcontroller (MCU) for the task.

Interested in learning more about the retro modern Nixie clock? You can check out the project’s official page loaded with additional images here.

Previous Nixie-based projects featured on Bits & Pieces include “The ATtiny1634 Nixie clock,”  “Building an Arduino-powered Enigma machine,” and “Atmel’s ATmega645P goes tick tock.”