Tag Archives: Electronics

Passive, but not Innocuous

via Hackaday » hardware

Maxim Integrated recently posted a series of application notes chronicling how there’s more going on than you’d think in even the simplest “passive” components. Nothing’s safe: capacitors, resistors, and even printed circuit boards can all behave in non-ideal ways, and that can bite you in the reflow-oven if you’re not aware of them.

You might already know that capacitors have an equivalent series resistance that limits how fast they can discharge, and an equivalent inductance that models departures from ideal behavior at higher frequencies. But did you know that ceramic capacitors can also act like voltage sources, acting piezoelectrically under physical stress?

For resistors, you’ll also have to reckon with temperature dependence as well as the same range of piezoelectric and inductance characteristics that capacitors display. Worse, resistors can display variable resistance under higher voltages, and actually produce a small amount of random noise: Johnson Noise that depends on the value of the resistance.

Finally, the third article in the series tackles the PCB, summarizing a lot of potential manufacturing defects to look out for, as well as covering the parasitic capacitance, leakage currents, and frequency dependence that the actual fiberglass layers themselves can introduce into your circuit.

If you’re having a feeling of déjà-vu, the same series of articles ran in 2013 in Electronic Design but they’re good enough that we hope you won’t mind the redundant repetition all over again. And if you’re already quibbling with exactly what they mean by “passive”, we feel your pain: they’re really talking about parasitic effects, but we’ll let that slide too. We’re in a giving mood today.

[via Dangerous Prototypes]

Filed under: hardware, how-to

Anatomy of the RollJam Wireless Car Hack

via Make: DIY Projects, How-Tos, Electronics, Crafts and Ideas for Makers » Category: Open Source Hardware

rolljam hardwareIf you’ve been on the internet lately, you’ve likely seen the storm of news of Samy Kamkar’s device that can intercept and store keyless entry codes for cars and garages. Built for under $50 using a Teensy 3.1 and a couple of radios, the “RollJam” device is said to allow its user […]

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The post Anatomy of the RollJam Wireless Car Hack appeared first on Make: DIY Projects, How-Tos, Electronics, Crafts and Ideas for Makers.

Adorable Automated Turret Launches Rubber Band Barrage

via Make: DIY Projects, How-Tos, Electronics, Crafts and Ideas for Makers » Category: Open Source Hardware

turretgifThis 3D printed rubber band launching turret looks like it popped right out of Portal.

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The post Adorable Automated Turret Launches Rubber Band Barrage appeared first on Make: DIY Projects, How-Tos, Electronics, Crafts and Ideas for Makers.

With Linux and Creative Commons, The $9 CHIP Computer Reveals Its Open Source Details

via Make: DIY Projects, How-Tos, Electronics, Crafts and Ideas for Makers » Category: Open Source Hardware

wf9We’ve been wondering exactly how open source CHIP, the $9 computer, is. Turns out, it’s really freaking open! The initial launch of CHIP from the Oakland, California-based Next Thing Co. made big waves a few months back with its capabilities and crazy-low price. Ultimately, the team raised over $2 million […]

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The post With Linux and Creative Commons, The $9 CHIP Computer Reveals Its Open Source Details appeared first on Make: DIY Projects, How-Tos, Electronics, Crafts and Ideas for Makers.

“I am a maker in the making”

via Arduino Blog

Rishalaser running on Arduino Mega

Moushira Elamrawy is an Egyptian multidisciplinary designer and technologist based in the city of Cairo and founder of Rishalaser, a new concept for laser cutters that is opensource, portable, DIY, and easy to use. She wrote a piece on iAfrikan about becoming a maker and discovering Arduino. It’s an inspiring text and we want to share it on this blog.



Confession: I used to be an architect (possibly still am!), and then I started tinkering with things.
The architecture engineering school I graduated from did not have a workshop space. The first time I met a CNC router in real life was three years after i graduated.

It is hard to discover what you don’t know even exists. Which is somehow, why I had zero imagination of how those awesome Theo Watson installations could possibly work.

I had no business fiddling with electronics whatsoever. My coding and programming skills were limited to some knowledge of ActionScript, some C, and that was about it.

I read about Openframeworks, installed it, went through examples, tutorials and thought “Nice, I can change parameters that in return would change behavior, fantastic..but ..then..what?!”

Rishalaser running on Arduino Mega

By that time, I was an architect working in Morocco, between an office that was based in Fez and a construction site based in a beautiful small southern village close to the Algerian borders, called Mhamid ElGhizlane. It normally took me a little over a day and a half to travel from Fez to the construction site.

I had a radio, which I considered my companion in those interesting border areas. Before Morocco, I was living in Sinai mountains, working on a similar desert development project, where the radio would normally catch signals of Saudi Arabia, Israel, and Jordan. The Moroccan Sahara, on the other hand, got me signals from Algeria, with lots of different dialects. Radio feels like travelling within time within places. It makes you really feel the distance you crossed.


In May 2012, I attended a beginners workshop for Arduino, lead by Bilal, who was visiting Egypt. During the workshop, I controlled an LED via Arduino.

It was magical.

I never used the board before, I barely understood any syntax, yet in 15 min, I did something cool . . that actually works. Arduino: I am in Love, I thought.

It is easy. It is just that starting alone isn’t easy. Going back home, I went through some examples and I felt oh..I can do stuff. I can do all these stuff actually. Oh, wait, there is also: Processing!

By September 2012, I moved to Barcelona for my masters, which started by a fabrication course in Fablab. I was Alice in wonderland. Then physical computing course started, and Alice’s wonderland was getting more vast.

Everything was awesome. The exact skill set that I wanted to learn. But I needed more, a lot more, time to absorb this whole new world. I thought of taking a gap year, but then, week after week, it turned out that once the ball gets rolling everything is accelerated.

Thanks actually to my sister for pushing me to trust that the ball will get rolling. She herself was moving from translation to graphics design one year before me. It is a family thing.

Arduino was THE treasure.

At the end of the day, all those fantastic surreal systems that I was fascinated by could be done with some components and an Arduino. The amount of associated open source resources is tremendous. The forum is awesome and people actually respond.

Through Arduino, I learned more about microcontrollers, I could program standalone circuits. Then the ball kept rolling, I learned eagle, I can mill some boards, I can solder (err, that was troublesome!), I can interface stuff, I can build sensors, I can work with data, I can build RF sensors, then I became obsessed with antennas, signal processing, and RFID.

I am still learning and learning, but it is much easier now.

Coming from this background, I always go back with time 4 or 5 years ago and recall how I used to react to a “closed box” new technology?

How life would have changed if machine interaction have been made easier, or basically how my life would have changed if machines had the opportunity to step out of their labs and talk to more people.

Making technology more portable and more accessible, is one reason why I started the mobile operated laser cutter project last year, of course, the project would have never been realized without the team that continued with enthusiasm.

Another wonderful project that I just co-started is Jebaleya Talks, with the hope of giving voice to women of Saint Katherine village in Sinai, by introducing them to smart textiles! Well, lets see how this will evolve..

While working in the desert in Sinai, the project foreman was my mentor, his words of wisdom still echo in my ears

“Everything comes along..with patience. If you could just wait”.

Apparently, he had a point!

E-mails are a distraction.

Meetings are boring.

Regular jobs suck your inner clock.

Take a sabbatical and learn what you want to learn and start anew.

At least try.

Oh, and during your sabbatical, give Arduino a try, it might change your life as well.

Let’s just hope that Arduino founders will keep embracing the same energy they started the project with, and that the big whales leave Arduino alone, so that it stays, open and libre just as how it helped liberate many creative energies and minds.

Keep reading on iAfrikan

Radio (HPSDR)


Radio spectrum is a finite resource and it should therefore come as no surprise that radio systems are a particularly hot area of research. Whilst ever more advanced schemes for modulation, digital encoding and spectrum access promise increased efficiency, step upgrades more often than not require new hardware. As has been evidenced in the evolution of mobile telephony from analogue to GSM and 2.5G (GPRS) to 3G, and similarly in the evolution of wireless computer networks. A disruptive development in radio technology promises to change this and to bring an unprecedented flexibility to radio systems, and one similar to that which programming brought to the task of machine computation. Despite, or perhaps due to being at the cutting edge there are a number of open source hardware projects concerned with developing software-defined radio (SDR) technology. As with the earliest developments in radio systems radio amateurs are once again at the forefront, and at this month's meeting we will have a presentation on the comprehensive HPSDR platform.

HPSDR - High Performance Software Defined Radio

HPSDR is an open source (GNU type) hardware and software project intended as the "next generation" software-defined radio for radio amateurs and shortwave listeners. It is being developed by a group of software-defined radio enthusiasts around the world, and in a modular hardware fashion to help promote experimentation by both hardware and software developers.

John Melton has held an amateur radio license since 1984 when he was first licensed as N6LYT while living and working in California, and he was assigned the UK callsign of G0ORX on moving back to the UK. He became interested in developing open source software in 1990 with the launch of AMSAT Oscar 16, an amateur radio satellite with a store and forward messaging payload. He developed an open source software package to communicate with the satellite that ran on Linux (pre 1.0) and subsequently wrote an open source fully automated satellite ground station software package in Java. John has been a software engineer since 1970 when he was employed by Burroughs Corporation, and for the last 14 years he has worked for Sun Microsystems who were acquired by Oracle this year.

slides [PDF]

Open Discussion - Ideas for Future Meetings

Themes, speakers, venues - it's all up for grabs! Have your say and help shape future OSHUG meetings. Offer to present, suggest a speaker or sit quietly until it's time to cross the road to the pub...