Posts Tagged led

Adapting to Mars aimee whitcroft Oct 12

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The subject of Mars is a popular one. Not only in science fiction but, of course, in real life, too.

Curiosity’s presence on the red planet at the moment – you can look at interactive panoramas of Mars! – has been generating a great deal of international media interest, and there has been talk of trying to get real actual human beans out there by the 2030s, if not before.

Click here to view the video on YouTube.

There are, of course, a number of challenges, many of which relate to the fragile state of our brains, bodies and minds.

We’ve had projects such as KiwiMars simulate life (and science!) in a ‘Martian’ evironment. The MARS-500 project shut people in a mocked-up spacecraft for 520 days to see whether all those movies about space crews cracking would actually happen*. Examples, basically, abound of people thinking Very Seriously about a human presence on Mars.

Another issue, though, apart from the food and stress and travel (WAY worse than airplanes and LAX) and everything else, is sleep.

Or, more precisely, our circadian rhythms – the biological ‘clock’ upon which our bodies run. Earth’s day is on the order of 24 hours long, and we’ve adapted to that. Well, mostly – our innate clock is about 24 hours 12 minutes. And it’s the progression on earth from day into night, and back again, which helps us keep our clocks in check.  If you’re wondering ‘well, why would we care about that?’, they’re intimately involved in a number of very important processes, including metabolism, sleep** and mood…

However, the length of a day on Mars is slightly longer – 12 hours 39 minutes.  Not a huge difference, sure, but apparently our bodies have great difficulty adjusting to this difference on a day to day basis.

But retraining our body clocks isn’t impossible.  And, indeed, the fix is remarkably low tech – it’s a combination of blue light and caffeine.

A paper recently published in the journal SLEEP details how 19 of the crew of the gruelling Phoenix Mars Lander mission in 2008 took part in a study looking at ways to help circadian rhythms readjust. In addition to the training all of the crew received, about how to use caffeine properly, how to properly arrange a dark, comfy bedroom, and how to be OK with not being superhuman, 19 crew members volunteered for a little bit more.

These crew members wore an ‘actigraph’ watch, which helped to monitor their sleep patters, and kept a work and sleep diary.  In exchange, they were given panels of blue LEDs at their workstations.  This short-wavelength light, it would seem, mad a difference, with 87% of the 19 synchronizing to the Martian clock.

Phoenix Mars Lander crew member Morten Bo Madsen sitting next to his workstation blue LED panel. Madsen worked on the robotic arm camera for the mission. Credit: University of Arizona

Pretty cool, and a wonderful example of how, with a bit of thought and cleverness, a very simple and cheap solution can have a marked effect :)

Of course, all I can think of is ‘Hooray!  One step closer to the 25 hour day!’…



Barger LK, Sullivan JP, Vincent AS, Fiedler ER, McKenna LM, Flynn-Evans EE, Gilliland K, Sipes WE, Smith PH, Brainard GC, & Lockley SW (2012). Learning to Live on a Mars Day: Fatigue Countermeasures during the Phoenix Mars Lander Mission. Sleep, 35 (10), 1423-35 PMID: 23024441



* I’m paraphrasing significantly.  More accurately, it was a ‘psychosocial experiment’, involving only men, which looked at a range of different situations. It was actually really, really cool :)

** Apparently, blind people also often suffer from sleep disorders because they don’t perceive the light/dark difference of day/night. And their body clocks adjust to something closer to the Martian day!

Cyborging aimee aimee whitcroft Jun 03

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UPDATE: moar pics here, here and here.

As mentioned, I broke my wrist a few weeks ago.

aimee aap

please note: I am _directly_ plugged into a computer here. * happy sigh *

Which caused me no small amount of unhappiness, given that I was soon to be travelling to the San Francisco Bay Area to, well, get my geek on :)

Thankfully, I am surrounded by other geeks, with strange and mysterious powers, and it was one of these that suggested that we cyborg me.  Because what else would one possibly do with a cast, right?

(Funnily enough, I’ve now had friends commenting on wishing they were casted up, so that they could attach circuitry to themselves :P  Further, I am wondering whether this might be the first time this has been done…)

And, even better, I would then be able to attend the SF MakerFaire thus modified.  There’s a quick video, taken there, of aap running.

For those of you interested in exactly what was done to me, I’ve had its designer/maker, Josh Bailey, explain below:


Aimee broke her wrist. What to do? Make use of the newly available inanimate surface area, of course. Behold the Aimee Arm Processor, recently modelled by Aimee at the San Francisco Bay Area Maker Faire.

Arduino’s [1] all the rage, and most other microcontrollers are merely players. Back in my day we had to LDA, STA uphill both ways through zero page, bank switching all the way [2], but with Arduino many things are embarrassingly easy. Aimee and I had been discussing cellular automata recently [3], and it was not too much of a challenge to find an Arduino board with sufficient guts to drive an LED matrix [4] (on rechargeable battery even). indeed. I ordered an Arduino Pro 328 (3.3V, 8MHz model), 8×8 LED matrix, and an 850mAh battery – the latter about the dimensions of a matchbook, and quite happily runs AAP for almost a week.

Low parts count was a specific design goal, so I went with the direct drive approach [5] – the LED matrix is directly connected to the processor’s I/O pins, and the magic is done in software (i.e. patterns are raster scanned [6] onto to the LEDs so only one row is actually lit at once, but you see more than than due to persistence of vision [7] – maybe Aimee will let me write something about narrow bandwidth mechanical TV [8] sometime – oops distracted). It is possible to drive multiple LED matrices but that would’ve added parts – though one imagines we could’ve broken Aimee’s other arm for more real estate. One imagines.

After a virtuous amount of soldering, swearing, and scorching myself with hot glue the pieces came together (I used an old Ethernet cable and some spare resistors). Sparkfun’s data sheets were incorrect, so had to do some reverse engineering to determine actually which pins controlled what rows/columns. A minor thing but always adds to one’s sense of accomplishment.

And the code? Well, I wrote my own and it is available on request; much example Conway/Arduino code uses interrupts [9] (implementing a convenient background task that updates the display for you) and copies 2D arrays back and forth (not particularly CPU efficient). Most Arduino processors have more than enough CPU for that – but I went with the interleaved, swap pointers for frame buffers approach [10]. More complex but seemed true to my 8 bit roots [11].


1. Ardunio – a bewilderingly awesome open source gem of hardware and software that makes it easy to build things that do anything from blink lights to fly unmanned aerial vehicles

2. My first computer of was a C64 – STA/LDA are 6502/6510 machine language instructions

3. So called artifical life – cells that live or die, by a small number of logical rules, generally within a 2 dimensional space – like Conway’s Game of Life

4. LED matrix – a grid of light emitting diodes, essentially efficient light bulbs that can be switched on or off to create images

5.  The direct drive approach

6. Raster scanning – in this context, building up a picture by drawing successive lines of pixels

7. The effect thought to be behind why humans perceive motion from rapidly presented images, called Persistence of Vision

8. Mechanical TV – or so called Narrow Bandwidth Television. Using a spinning disc or mirror to draw a picture

9. Interrupt – a way for hardware or software to grab a processor’s attention for something and then return it to where it left off.

10. Frame buffer – in this context, an area of memory used to describe which LEDs should be on or off

11. I’m old, another reference to C64s.


So yeah.  That’s how it’s done, peeps.  Stay tuned for other such techie tales :P  Also, an interesting notion: using the Conway Glider as an emblem for hackers…

[oh, and P.S. I figured out what was causing issues with comments section, so feel free to comment in the knowledge that it will not disappear]

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