Into the heart of darkness

Life is not all joy and fun, but often dark, depressing and painful.

Easter and Christmas are part of popular culture: Easter bunnies, Easter eggs, Christmas presents and Santa Claus. However, except for the odd Hot Cross Bun, Good Friday slips under the radar. The birth of a child and the glory of renewed life are images that are obvious causes for celebration, but a tale of abandonment followed by painful and bloody execution maybe has Gothic overtones, but is hardly party-worthy.

And yet, for those of different and no faith as well as for Christians, Good Friday touches issues of mythic as well as deeply personal significance.

Sometimes we simply need someone to share the darkness with us.

In days past the season of Lent with its fasting and sobriety helped build a sombre tension. Reading the Gospel accounts of Easter week is like one of those disaster films, where life appears to go on as normal, but with small and growing signs of the catastrophe to come. While we also know of the Easter story that follows, this does not shield us from the deep pit of despair that precedes it, “My God, My God, why have you forsaken me1.

I love Nina Bawden‘s books for children, and often in them are very real and flawed characters who, while young, can sometimes cause real pain and harm; they dig at one’s own buried memories and knowledge of our own flaws.

The Easter story is full of such characters, Peter falling asleep as Jesus prayed in Gethsemane, just at the point he was needed most as a friend; and later, after Jesus was arrested, in fear for his own life, denying that he ever knew Jesus. Each time I read it part of me wants to shout at him, warn him, encourage him, knowing that in his position I would do the same.

And Judas, the friend turned betrayer. Just like the actions of Lubitiz, who crashed the plane in the alps, many have speculated on the reasons in Judas’ heart: disillusionment that Jesus was not going to oust the Romans, greed for the bribe of silver, self-destruction, or maybe simply that bitter rancour in the presence of someone better than ourselves.

The 1960s protest song “There but for fortune” talks of the prisoner, the hobo, the drunk and the war-torn, but now I often think of the Auschwitz guard, the Rwandan militia, the ISIS terrorist — what are the life chances and life choices that brought me to where I am compared to those that took them?

Reading of Judas his betrayal, his remorse, throwing the tainted money back at the Priests’ feet, and taking his own life — there but for fortune.

And it is no accident that the blood money, the price of a life, the price of Jesus’ life, was used to buy a burial ground for strangers and foreigners2. The death of one who sought out the marginal, the poor, the disabled, and the ‘immoral’ buys a resting place for the same.

Jesus death on the cross is, of course, at the heart of Christian theology, Paul once wrote to early converts on Corinth, “I resolved to know nothing while I was with you except Jesus Christ and him crucified.”3. The main focus is often on sacrifice, both personal, “greater love has no man than he lay down his life for his friends4, and also theological, cosmic atonement for sins.

However, as well as this message that Jesus died for us, there is also a parallel message, that Jesus died with us, alongside us in the darkest hour. This is the end point of the Christmas story, one who was “like us in every respect5, entering the world, a tiny head crowned in the blood of childbirth, and leaving crowned by bloody thorns.

While the early Church was never at doubt as to the resurrection of Jesus, the completeness of this moment, Jesus dying, flanked by criminals and a weeping prostitute at his feet, is so intense that the earliest versions of Mark’s gospel rush through the Easter morning itself in a mere 8 verses, and end with the empty tomb, the astonished disciples and the words, “for they were afraid6.

The Apostles’ Creed repeated in various forms across all Western churches says Jesus “was crucified, died and was buried; he descended into hell“. Hell is not an easy concept for the modern mind, filled with images of half-comic horned demons. But despite its B-movie connotations, and irrespective of whether you read it literally, figuratively or mythically, Hades, Gehenna, the pit are powerful images.

Hell of 1st century Palestine is not just for the lifeless shades of Greek Hades, but more like Tartarus, the place of damnation, the abode of the sinner. Peter says that Jesus “preached to the dead7, and other authors simply that death could not ultimately hold him8, but all agree that for three days that was where Jesus was, not simply dying for and with us, but entering the very place of the Auschwitz guard, of Judas, of the ISIS killer, of our own deepest darkness, and sharing it.

The one of whom they said, “Here is a glutton and a drunkard, a friend of tax collectors and sinners9, the one who spent his life with outcasts and prostitutes, would he be anywhere else?


  1. Matthew 27:46[back]
  2. Matthew 27:3-8[back]
  3. 1 Corinthians 2:2[back]
  4. John 15:13[back]
  5. Hebrews 2:17[back]
  6. Mark 6:8[back]
  7. 1 Peter 4:6[back]
  8. Acts 2:24[back]
  9. Matthew 11:19[back]

If the light is on, they can hear (and now see) you

hello-barbie-matel-from-guardianFollowing Samsung’s warning that its television sets can listen into your conversations1, and Barbie’s, even more scary, doll that listens to children in their homes and broadcasts this to the internet2, the latest ‘advances’ make it possible to be seen even when the curtains are closed and you thought you were private.

For many years it has been possible for security services, or for that matter sophisticated industrial espionage, to pick up sounds based on incandescent light bulbs.

The technology itself is not that complicated, vibrations in the room are transmitted to the filament, which minutely changes its electrical characteristics. The only complication is extracting the high-frequency signal from the power line.

040426-N-7949W-007However, this is a fairly normal challenge for high-end listening devices. Years ago when I was working with submarine designers at Slingsby, we were using the magnetic signature of power running through undersea cables to detect where they were for repair. The magnetic signatures were up to 10,000 times weaker than the ‘noise’ from the Earth’s own magnetic field, but we were able to detect the cables with pin-point accuracy3. Military technology for this is far more advanced.

The main problem is the raw computational power needed to process the mass of data coming from even a single lightbulb, but that has never been a barrier for GCHQ or the NSA, and indeed, with cheap RaspberryPi-based super-computers, now not far from the hobbyist’s budget4.

Using the fact that each lightbulb reacts slightly differently to sound, means that it is, in principle, possible to not only listen into conversations, but work out which house and room they come from by simply adding listening equipment at a neighbourhood sub-station.

The benefits of this to security services are obvious. Whereas planting bugs involves access to a building, and all other techniques involve at least some level of targeting, lightbulb-based monitoring could simply be installed, for example, in a neighbourhood known for extremist views and programmed to listen for key words such as ‘explosive’.

For a while, it seemed that the increasing popularity of LED lightbulbs might end this. This is not because LEDs do not have an electrical response to vibrations, but because of the 12V step down transformers between the light and the mains.

Of course, there are plenty of other ways to listen into someone in their home, from obvious bugs to laser-beams bounced of glass (you can even get plans to build one of your own at Instructables), or even, as MIT researchers recently demonstrated at SIGGRAPH, picking up the images of vibrations on video of a glass of water, a crisp packet, and even the leaves of a potted plant5. However, these are all much more active and involve having an explicit suspect.

Similarly blanket internet and telephone monitoring have applications, as was used for a period to track Osama bin Laden’s movements6, but net-savvy terrorists and criminals are able to use encryption or bypass the net entirely by exchanging USB sticks.

However, while the transformer attenuates the acoustic back-signal from LEDs, this only takes more sensitive listening equipment and more computation, a lot easier than a vibrating pot-plant on video!

So you might just think to turn up the radio, or talk in a whisper. Of course, as you’ve guessed by now, and, as with all these surveillance techniques, simply yet more computation.

Once the barriers of LEDs are overcome, they hold another surprise. Every LED not only emits light, but acts as a tiny, albeit inefficient, light detector (there’s even an Arduino project to use this principle).   The output of this is a small change in DC current, which is hard to localise, but ambient sound vibrations act as a modulator, allowing, again in principle, both remote detection and localisation of light.

220px-60_LED_3W_Spot_Light_eq_25WIf you have several LEDs, they can be used to make a rudimentary camera7. Each LED lightbulb uses a small array of LEDs to create a bright enough light. So, this effectively becomes a very-low-resolution video camera, a bit like a fly’s compound eye.

While each image is of very low quality, any movement, either of the light itself (hanging pendant lights are especially good), or of objects in the room, can improve the image. This is rather like the principle we used in FireFly display8, where text mapped onto a very low-resolution LED pixel display is unreadable when stationary, but absolutely clear when moving.

pix-11  pix-21
pix-12  pix-22
LEDs produce multiple very-low-resolution image views due to small vibrations and movement9.

Sufficient images and processing can recover an image.

So far MI5 has not commented on whether it uses, or plans to use this technology itself, nor whether it has benefited from information gathered using it by other agencies. Of course its usual response is to ‘neither confirm nor deny’ such things, so without another Edward Snowden, we will probably never know.

So, next time you sit with a coffee in your living room, be careful what you do, the light is watching you.

  1. Not in front of the telly: Warning over ‘listening’ TV. BBC News, 9 Feb 2015.[back]
  2. Privacy fears over ‘smart’ Barbie that can listen to your kids. Samuel Gibbs, The Guardian, 13 March 2015.[back]
  3. “Three DSP tricks”, Alan Dix, 1998.[back]
  4. “Raspberry Pi at Southampton: Steps to make a Raspberry Pi Supercomputer”,[back]
  5. A. Davis, M. Rubinstein, N. Wadhwa, G. Mysore, F. Durand and W. Freeman (2014). The Visual Microphone: Passive Recovery of Sound from Video. ACM Transactions on Graphics (Proc. SIGGRAPH), 33(4):79:1–79:10[back]
  6. Tracking Use of Bin Laden’s Satellite Phone, all Street Journal, Evan Perez, Wall Street Journal, 28th May, 2008.[back]
  7. Blinkenlight, LED Camera.[back]
  8. Angie Chandler, Joe Finney, Carl Lewis, and Alan Dix. 2009. Toward emergent technology for blended public displays. In Proceedings of the 11th international conference on Ubiquitous computing (UbiComp ’09). ACM, New York, NY, USA, 101-104. DOI=10.1145/1620545.1620562[back]
  9. Note using simulated images; getting some real ones may be my next Tiree Tech Wave project.[back]