Tag Archives: homebrew

Homebrewing a DIY pulse monitor

A 15-year-old Maker by the name of Angelo has designed a homebrew pulse monitor using an Atmel based Arduino board, a grippy clothes hanger, clear/bright red LED and a light dependent resistor (LDR).

The project — which can be found on Instructables — was inspired by MAKE Magazine’s homemade pulse monitor.

“Movies look cool with those EKG (electrocardiogram), the one that beeps and detects heart activities. A few months ago, we had to shoot a hospital scene for our school project. We needed an EKG instrument,” Angelo explains.

“To keep the movie authentic, we didn’t want to fake the readings so we made the next best thing, a pulse monitor. This project works and can actually monitor your pulse. [However], due to the lack of research and experimentation, the homebrew pulse monitor cannot be used for medical purposes.”

Have a friend or foe who continuously tells fibs? Good news! According to Angelo, the homebrew device can even be used as a rudimentary lie detector.

“When a person lies, you’ll notice a sudden change on the [pulse] graph,” he said.

On the software side, Angelo employs Processing 2 for graphing, along with a specially coded Arduino IDE sketch. Both are required to run the homebrew project.

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

Arduino-based satellites for the homebrew masses

Arduino boards are used to power a wide range of electronic designs and DIY hobbyist creations including robots, desk lamps, environmental sensors, 3D printers and even satellites.

Indeed, the San Francisco-based Nanosatisfi is currently prepping two Arduino-powered satellites (ArduSat) for launch on an unmanned HII-B rocket, which Kickstarter backers have “rented” to snap pictures, broadcast a message or conduct experiments, including monitoring radioactivity levels generated by space phenomena such as sun storms and background activity.

According to Nanosatisfi CEO Peter Platzer, Arduino technology is key to the company’s philosophy.

“I’ve really wanted to use something that everyone across the world can use, that has wide appeal to everyday people,” Platzer recently told NPR. “There really was no alternative.”

To be sure, ArduSat is designed to give ordinary people – students, teachers, individuals and enterprises – the chance to carry out experiments by controlling over 25 different sensors integrated in the unit, (spectrometer, magnetometer, radiation, camera, gyroscope, accelerometer, temperature, etc.)

As noted above, the goal of the ArduSat project is to make space accessible to consumers, relatively cheaply.

Unsurprisingly, Atmel-powered Arduino boards are also widely used in the art world, with Alberto Gaitán, a Washington, D.C.-based artist, telling NPR  that Ardunio’s popularity is “growing, and growing fast.”

For example, an artist by the name of Joyce Yu-Jean Lee told NPR she wanted to use the Arduino in her next video art project.

“I’ve been wanting for a very long time – since graduate school – to work with sensors to make my videos interact with the viewers,” she explained. “I’ll have a solo show in the fall. I think I can get it down by then.”

And why not? As Arduino’s Massimo Banzi says, you don’t need anyone’s permission to make something great.

Atmel ATMegas power this homebrew 16-core computer

A talented Maker by the name of Jack Eisenmann has designed a multi-core homebrew computer using 16 ATMega328P microcontrollers.

“The DUO Mega is a multi-core 8-bit computer featuring a robust operating system. The goals of the system are to be efficient, reliable, easy to use, and open source,” Eisenmann explained in an extensive design breakdown posted on OstraCodfiles.com.

“The concepts of this computer should be expandable with more cores, additional memory and alternative processor models.”

According to Eisenmann, each core consists of a single ATMega microcontroller. More specifically, there are actually two types of core: worker and manager (15 worker cores + 1 manager = 16 total cores).

“Cores all share an 8 bit data bus. This data bus sends commands and information between cores. A worker core may not use the data bus unless permitted by the manager core. Each worker core is addressed by an 8 bit identifier,” he continued.

“When the machine starts up, the manager core poles every identifier to find worker cores. Then the manager loads instructions from flash memory into worker cores. The manager core may then behave as an interface for flash read and write operations.”

Eisenmann also noted that the DUO Mega is equipped with a single pool of shared memory in a 32 KB SRAM chip. Meaning, the manager core is responsible for access to shared memory – while also interfacing with peripheral devices.

On the software side, the OS user interface (UI) is based on a stack of windows, with  the DUO Mega supporting color text graphics and windows with 80 by 6 characters. All programs are written in Megaliter bytecode interpreted by the worker cores.

“Each program will run on at least one worker core. The number of worker cores allocated to a program depends on user preference. When the user opens a program, the operating system will first prompt the user for the number of cores to allocate,” said Eisenmann.

“One window will be dedicated to the operating system. This window is called the manager window, and cannot be closed. The manager window displays program information, a clock, files, directories and other useful information.”

Additional information about the Atmel-powered Duo Mega, including a full spec breakdown, can be found here.