Computing stuff tied to the physical world

Archive for December 2015

Turning the page on 2015

In Book on Dec 29, 2015 at 23:01

As the last few days of 2015 pass, I’d like to reflect on the recent past but also look forward to things to come. For one, the JeeLabs weblog is now thriving again: the new weekly post-plus-articles format has turned out to suit me well. It keeps me going, it’s oodles of fun to do, and it avoids that previous trap of getting forced into too-frequent daily commitments.

Apart from a summer break, every week in 2015 has been an opportunity to explore and experiment with physical computing topics, several ARM µCs, and various software ideas.

Here are the last two articles for 2015:

I’d like to close off 2015 with a deeply worrisome but nevertheless hopeful note. While this is a totally technology-focused weblog, it has not escaped me that we live in very troubling times. Never in history have so many people been on the run, fleeing home and country for the most basic of all human needs: a safe place to live. We’ve all seen Aryan Kurdi’s fate:

Aylan kurdi

An innocent three-year old boy, born in the wrong place at the wrong time, trying to escape from armed conflict. He could have been me, he could have been you. His tragic fate and that of many others could have been avoided. Europe offers a peaceful and prosperous home for half a billion people – accommodating one percent more is the least we can do.

I’m proud to see countries rise to the occasion, and put humanity and the planet first. Let’s cherish our compassion as well as our passion, our understanding as well as our creativity. For 2016, I wish you and yours a very open, respectful, and empathy-rich planet.

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Tying up 2015’s loose ends

In Book on Dec 23, 2015 at 00:01

As the end of 2015 is approaching and now that the new server setup has been completed, it’s time to clean up some remaining loose ends. Spring cleaning is early, here at JeeLabs!

Next week will be a good time for reflection and my new year’s resolutions. For now, I just want to go into some topics which didn’t seem to fit anywhere else. In daily doses, as usual:

I’m pleased with the new Odroid XU4 server so far. The Mac Mini is being re-purposed as Liesbeth’s new Mac – a nice SSD-based setup with 8 GB of RAM. Its Core 2 Duo @ 2.66 GHz will be a step up from the 5-year old 1.4 GHz MacBook Air’s she’s been working on.

Which frees up that 11″ MBA for my own portable use again – it’s a fantastic little laptop!

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Switching to a new server

In Book on Dec 16, 2015 at 00:01

As you may know, the various websites here at JeeLabs are served locally. Houten offers very fast Fiber-To-The-Home connections, my ISP (XS4ALL) is excellent, and I don’t see the point of putting everything in the cloud. Sure, it’s a bit more work to keep going, but this way I can delude myself into thinking that I am “the master of my own universe” …

This Mac Mini server has been doing all the work for several years now:

Screen shot 2010 06 15 at 124120

But for various reasons it’s now time to revisit that setup and simplify things further:

As you’ll see, I’m jettisoning a lot of dead weight. The resulting server is much cheaper, consumes far less energy, is more robust, has fewer moving parts, is easier to manage, and handles page requests much faster than before. What is there not to like about this, eh?

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A diversion into FPGAs

In Book on Dec 9, 2015 at 00:01

Last week’s exploration of “processing with limited computing power” a few decades ago has led me into another direction which turned out to be mesmerising and addictive…

All due to a chip called a Field Programmable Logic Array, which usually looks like this:


That’s a lot of pins – large FPGA’s can have over 1,000 pins, in fact!

What are they? What’s the point? Why are they so hard to use? Can we play with them?

Read on to find out, as usual there will be articles coming this week to explore the “field”:

Once again, there is an awful lot of ground to cover this week, but with a bit of luck, it’ll end up being a decent bird’s eye view of what this FPGA (and CPLD) stuff is all about…

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A fingernail vs a moon lander

In Book on Dec 2, 2015 at 00:01

Small microcontroller chips, modern laptops/desktops – the range of computing power is enormous nowadays. So enormous, that it can be pretty hard to grasp the magnitude.

Screen Shot 2015 12 02 at 14 34 29

This week, I’m going to do some explorations, using a HY-Tiny board with an STM32F103 on it. Or to be put it differently: a fairly low-end but popular 32-bit ARM Cortex M3 µC, running at 72 MHz, with 128 KB flash and 20 KB RAM. It draws up to 40 mA at 3.3V.

Let’s find out what this little gadget is capable of:

So there you have it: a µC the size of a fingernail, vastly outperforming the Apollo Guidance Computer used to put man on the moon, less than half a century ago. You’ve got to wonder: would we still be able to perform this feat, using just an STM32F103? – I have my doubts…

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