Tuesday, 23 June 2009

The quest for Invisible White Light continues...

In a recent comment concerning this investigation, Dr. Alcock correctly pointed out that I was in need of some beer and a lie down. However, he later forwarded me a photograph of his own TV remote control taken with his camera phone, demonstrating (a) the variation in response of different imaging elements to invisible radiation, and (b) that Dr. Alcock himself was in need of some beer and a lie down.
As I had just completed repairs to my large array of IR LEDs (see last post), I decided to compare what my camera could see with what my phone could see.
Below: A photo of the array taken with my camera - green, as expected. Still not very bright though. It appears the green sensors are only marginally receptive to IR and the red and blue sensors scarcely at all.
Below: My phone appears highly sensitive to IR, the red and blue sensors more so than the green.

And they say the camera never lies...

Saturday, 20 June 2009

Progress with Invisible White Light

The story so far...

I needed to get some measurements on the response of my camera to invisible light radiation. Here I took a photo of myself (in a mirror) illuminated by ultraviolet light. I could not actually see the light myself but the camera could, as you may see. If you grab a sample of my face and run it through a colour histogram tool (e.g. in PaintShop Pro) you will see that red and blue are very much in evidence and green scarcely at all (the tiny amount of green present is due to ambient light interference - I really should have done this experiment in the dark). So there you have it. That's what I call Ultra Magenta - the red and blue sensors in the imaging chip responding inappropriately but usefully to ultra violet light.

That's the red and blue sorted out. What about the green? That's where I need to infill with the infra red, which looks green to the camera.

I have tried but I cannot illuminate my face sufficiently using even a score of old TV remote control handsets. Here's the solution:
A large array of IR LEDs. Got to get it working first. Watch this space...

Friday, 19 June 2009

Invisible White Light!

Further to my last post, I've just discovered Ultra Magenta! It's not really ultra magenta of course - that's just my name for it. I experimented further with my digital camera and discovered that it could also see ultraviolet, which the blue and red sensors render as a kind of visible magenta!

Add my ultra magenta to my infra green (see previous post) and you've got invisible white light!

Think about it - a flash unit with an infra red and an ultraviolet source, both invisible to the human eye but the camera sees it as white light! The ultimate unobtrusive flash.

No - this is too good. It's probably been done...

I need to do tests, tests, yes, tests (mutter mutter...)

Infra Green?

It's not every day that someone discovers a new colour so I thought I'd mention this latest find from the Secret Laboratory - Infra Green. That's right - never been seen before, I reckon.

OK, it's not really a new colour. I was mucking about with my digital camera when I noticed that it could actually "see" the invisible infra red radiation from my TV remote control. Oddly, it rendered this invisible wavelength from the far red end of the spectrum not in red but in green - the exact complement in at least one colour model! If you're looking for green (e.g. through a green filter) the last thing you expect to see is red - it ought to be black! There's probably a perfectly reasonable explanation why my camera's green sensors (and green alone) are able to see infra red but I am not in possession of that explanation. It's probably something to do with what scientists call weird shit or quantum bollocks or something.

Of course, this is how those infra red security cameras work. Normally we view the images in black-and-white so we're not really aware what colour of sensor actually recorded the image. I always imagined one needed a special sensor to record infra red - not so...

Anyway, this got me to wondering what else my camera could see that I couldn't, and what other lies it was telling me when I released the shutter.

Then came the bombshell! What's the problem with flash photography? Too white and too bright! Suppose you had an infra-red flashgun - that would provide the necessary green signal without startling your subjects. Then infill with just a touch of visible magenta flash to balance the colour to ambient levels. Result? A very unobtrusive flash, no more than a pinky glow at 2/3 the apparent brightness of a conventional flash.

More news soon...

Friday, 12 June 2009

Mandolin Stuff

Mandolins are a bugger. Were I a guitarist of note there would be millions of guitarists to compare me with and demonstrate that I'm a guitarist of relatively poor achievement. When it comes to famous mandolin players, it's like the old business of trying to name famous Belgians. There are loads of them but nobody quite recalls them. Thus, it is incumbent upon me to represent famous mandolin players in Ledbury, even though I only know half-a-dozen chords and thrash them out like I am trying to saw a biscuit tin in half with a junior hacksaw.
Talking of which, why do I get funny looks when I go into Rodway's and ask for the Adult hacksaw section?
Cutting to the main story, an acquaintance of mine brought an ancient mandolin to me, explaining that it had been a gift and that he wanted to know if it could be rendered "playable". Looking at the poor thing, it was indeed in bad shape. I took it home for further inspection. Peering through the soundhole I could see the Vicar's house through the back - and the Vicar waving - not the best sign for a mandolin. The neck had been replaced at some point in its history and had been set at the wrong angle, producing an unplayably high action. The tailpiece was shattered - generally speaking, it's a good idea to have something to tie the ends of the strings to. The face was sunken, like your granny's cheeks when she tries to smoke a tightly rolled ciggie.
However, the Secret Laboratory loves a challenge...
Back glued together, no more gaps. French Polish applied!
New tailpiece! Bit of old scrap alu found in the dark recesses of the Secret Laboratory.

Some Abalone used to replace the missing Mother-of-Pearl inlay.
In short, this mando is now just about playable. I've worked on the action but I just can't get it down any further - there's no room. The sound, however, is astonishing! I wish my regular mando sounded so bright.
By the way, I can thoroughly recommend "The Secret of Successful French Polishing" [Lindsey Doyle].

Friday, 5 June 2009

Full Circle!

If you were thinking of entering this month's What's Happening in the Secret Laboratory competition, don't bother - you're too late. The prize jelly babies have gone to a good cause.

I was, of course, measuring the water flow rate through a concrete griffin's bottom and the back pressure on the pump. Why? Read on...

Followers of exploits at the Secret Laboratory (pre-dating this blog) may remember that a few years ago I converted a garden water feature to serve as an automatic tomato watering facility so that I could go on holiday, safe in the knowledge that there would be tomatoes upon my return. This year I didn't bother with tomatoes so I came around to thinking maybe I could convert this converted garden water feature into... a garden water feature. A crazy idea but it might just work...

Let me introduce my Dad (1928-1998), a man filled with grandiose ideas and a master of unfinished projects. In 1970 he bought a concrete griffin with an internal tube connecting its bum to its mouth. Our garden was to become a veritable water palace, worthy of kings and princes. All summer long my Mum and I waited for the sound of tinkling water. All summer long the griffin lay idle, gathering moss. Thirty-nine years later, still not a drop of water had entered the griffin's bottom to delight visiting nobles - until now!

The best thing is, turn a valve, engage the timer and the installation reverts to an automatic tomato irrigation tool again!
Yes, yes - I have to do some work on hiding the beer line and the power cable. Everything's under control...

This one is for you Dad - a gift from the Secret Laboratory!

Thursday, 4 June 2009

Work in Progress...

So, what is happening at the Secret Laboratory this week? A bag of jelly babies says you'll never guess.