Slider

5064 Articles

Where 3000MPG+ Cars Come To Compete: The Ecomarathon

April 15, 2015 by 65 Comments

Every year teams from around the world come together for the Ecomarathon, an event (ironically put on by Shell) that tasks teams from high schools and universities with creating energy-efficient electric, gas, and hybrid vehicles. This year’s competition was held in Detroit, so I headed over to check it out.

vehicle-blurThe event has two categories that vehicles compete in: prototype vehicles that compete for the highest fuel efficiency and “urban concept” vehicles that are more focused on normal driving environments and look slightly closer to street-legal vehicles. Cars in both categories can be fully electric or powered by gas, diesel, compressed natural gas, or other alternative fuels. Vehicles drive around a 0.9 mile track that weaves through downtown Detroit and the efficiency of each vehicle is measured as they complete a fixed number of laps around the track.

Continue reading “Where 3000MPG+ Cars Come To Compete: The Ecomarathon” →

Peripherals Behind The Iron Curtain

April 13, 2015 by 39 Comments

The article Home Computers Behind the Iron Curtain sparked a lot of interest, which made me very happy. Therefore, I decided to introduce more computer curiosities from the Iron Curtain period, especially from the former Czechoslovakia (CSSR).

As I mentioned in the previous article, the lack of spare parts, literature and technology in Czechoslovakia forced geeks to solve it themselves: by improvisation and what we would today call “hacking.”  Hobbyist projects of one person or a small party was eventually taken over by a state-owned enterprise, which then began to manufacture and deliver to stores with some minor modifications. These projects most often involved a variety of peripherals that could only be found in the Czechoslovakia with great difficulty.

Much like the production of components, the production of peripherals was also distributed throughout the eastern block so that each country was specializing in certain types of peripherals. For example, East Germany produced matrix printers, and Bulgaria made floppy disks drives. This meant industrial enterprises had to wait for vital computer parts, because the production in another country was not sufficient to cover even the local requirements, let alone the home user.

Continue reading “Peripherals Behind The Iron Curtain” →

Logic Noise: More CMOS Cowbell!

April 10, 2015 by 23 Comments

Logic Noise is an exploration of building raw synthesizers with CMOS logic chips. This session, we’ll tackle things like bells, gongs, cymbals and yes, cowbells that have a high degree of non-harmonically related content in them.

Metallic Sounds: The XOR

I use the term “Non-harmonic” in the sense that the frequencies that compose the sound aren’t even integer multiples of some fundamental pitch as is the case with a guitar string or even our square waves. To make these metallic sounds, we’re going to need to mess things up a little bit, and the logic function we’re introducing today to do it is the exclusive-or (XOR).

Continue reading “Logic Noise: More CMOS Cowbell!” →

Open Hardware For Open Science – Interview With Charles Fracchia

April 8, 2015 by 14 Comments

Open Science has been a long-standing ideal for many researchers and practitioners around the world. It advocates the open sharing of scientific research, data, processes, and tools and encourages open collaboration. While not without challenges, this mode of scientific research has the potential to change the entire course of science, allowing for more rigorous peer-review and large-scale scientific projects, accelerating progress, and enabling otherwise unimaginable discoveries.

As with any great idea, there are a number of obstacles to such a thing going mainstream. The biggest one is certainly the existing incentive system that lies at the foundation of the academic world. A limited number of opportunities, relentless competition, and pressure to “publish or perish” usually end up incentivizing exactly the opposite – keeping results closed and doing everything to gain a competitive edge. Still, against all odds, a number of successful Open Science projects are out there in the wild, making profound impacts on their respective fields. HapMap Project, OpenWorm, Sloan Digital Sky Survey and Polymath Project are just a few to name. And the whole movement is just getting started.

While some of these challenges are universal, when it comes to Biology and Biomedical Engineering, the road to Open Science is paved with problems that will go beyond crafting proper incentives for researchers and academic institutions.

It will require building hardware.

Continue reading “Open Hardware For Open Science – Interview With Charles Fracchia” →

Build A Phased-Array Radar In Your Garage That Sees Through Walls

April 7, 2015 by 63 Comments

Until recently phased array radar has been very expensive, used only for military applications where the cost of survival weighs in the balance. With the advent of low-cost microwave devices and unconventional architecture phased array radar is now within the reach of the hobbyist and consumer electronics developer. In this post we will review the basics of phased-array radar and show examples of how to make low-cost short-range phased array radar systems — I built the one seen here in my garage! Sense more with more elements by making phase array your next radar project.

Phased array radar

In a previous post the basics of radar were described where a typical radar system is made up of a large parabolic antenna that rotates. The microwave beam projected by this antenna is swept over the horizon as it rotates. Scattered pulses from targets are displayed on a polar display known as a Plan Position Indicator (PPI).

Block diagram of a conventional radar system using a parabolic dish.
Block diagram of a conventional radar system using a parabolic dish.

In a phased array radar (PDF) system an array of antenna elements are used instead of the dish. These elements are phase-coherent, meaning they are all phase-referenced to the same transmitter and receiver. Each element is wired in series with a phase shifter that can be adjusted arbitrarily by the radar’s control system. A beam of microwave energy is focused by applying a phase rotation to each phase shifter. This beam can be directed anywhere within the array’s field of view. To scan the beam rotate the phases of the phase shifters accordingly. Like the rotating parabolic dish, a phased array can scan the horizon but without the use of moving parts.

Continue reading “Build A Phased-Array Radar In Your Garage That Sees Through Walls” →

How To Build A Thermocouple Amplifier

April 6, 2015 by 54 Comments

A Thermocouple is a terrific way to measure temperature. The effects of temperature change on dissimilar metals produces a measurable voltage. But to make that measurement you need an amplifier circuit designed for the thermocouple being used.

Linear Technology LTC 1049 Low Power Zero-Drift Operational Amplifier with Internal Capacitors
Linear Technology LTC 1049 Low Power Zero-Drift Operational Amplifier
with Internal Capacitors

While researching “Zero Drift Amplifiers” as a follow-up to my video on Instrumentation Amplifiers I noticed the little schematic the front page of the LTC1049 datasheet which is shown here. I thought it was an ideal example of an analog application where some gain and some “gain helper” were needed to accomplish our useful little application of amplifying a thermocouple probe.

In the video I don’t really talk much about the thermocouples themselves other than the type I see most of the time which is type K. If you’re not already familiar with the construction of these probes you can find an informative write-up on thermocouples and the different types on the Wikipedia page and you might also want to check out the Analog Devices app note if you would like to know more. What I will cover is a reliable and precise way to read from these probes, seen in the video below and the remainder of the post after the break.

Continue reading “How To Build A Thermocouple Amplifier” →

The Raspberry Pi Wearable Revolution

April 1, 2015 by 44 Comments

With the human URL [will.i.am] serving as Chief Creative Director of 3D Systems, and [Martha Stewart] selling her own line of 3D printer filament through MakerBot, more and more celebrities are piling onto the hacker, maker, and DIY revolution. Now, the partnership we’ve all been waiting for: the Raspberry Pi Foundation and [The Artist Formerly Known As Prince_logo] are teaming up to produce a line of Pi-based wearable electronics. The first product from this new, fashionable line of electronics is beyond anything you would expect. It’s called the Raspberry Beret, and it’s shaping up to be a Revolution in wearables.

The wearable Raspberry Beret is exactly what you would expect: a habadasher’s masterpiece that pairs equally well with figure skating costumes and skin-tight cloud print suits. Inside, though, is a new piece of hardware based on the Raspberry Pi compute module. This module includes a Bluetooth module that will sync with any Windows phone. The Raspberry Beret also includes enough sensors that will blow away everything from a Fitbit to the new Apple Watch. The Raspberet will keep track of your heart rate, activity, and exercise routine.

The Raspberry Beret is just the beginning; the Pi Foundation and [The Artist Formerly Known As Prince_logo] are also teaming up with OSH Park to produce a limited, special edition Raspberry Pi 2. This board will be clad in the beautiful OSH Park purple soldermask and sports 4GB of eMMC Flash. This Flash will not be usable; instead it will contain a remastered edition of Purple Rain that will play as a startup chime. There will be no option to skip the chime.

Pancakes.