How a Biologist Builds a Digital Camera


okay this is super weird because I can’t
see, you guys… but hello YouTube! I’m Kurtis Baute and this is the Scope of
Science and I just built I built a digital camera. Okay wait a
second, we’re gonna start from the very beginning. You see, this isn’t really a
video about the camera that I built but it’s about how I built it. People often
ask how the eye, in all its complexity, could have possibly evolved, and I
actually think it’s a great example of evolution. Now since the eye is actually a lot like camera – well the camera is a lot like an
eye – I’ve decided to evolve a digital camera, one step at a time, so that at
each step it still worked. So this is that process. I start by making something
that can sense light it’s a photocell and I’m going to make mine using a
copper penny. You see metals like copper give off
electrons when they’re exposed to light and by adding some heat and some
saltwater to a plate of copper I can actually make that effect big enough
that I can measure it. Animals also see light by using chemistry and electrical
charges just instead of copper its proteins and instead of wires it’s
neurons. Now I can take the number value that I get and represent it as a degree
of brightness a lower number is darker and a higher number is brighter. Now to
make a camera I’m gonna need a lot of these but since I don’t have 2.8 billion
years to evolve the camera (and that’s how long it took for life to evolve
vision) I’m just gonna take a couple short cuts and I’m gonna order a bunch
off of Amazon. This photocell is more compact than my penny but if I connect
it to my Arduino brain-computer thing I can use it in pretty much the same way.
If I put a bunch of these photocells together I get a sensor and now I can
measure light even better and now I can finally start to tell if maybe there’s a
predator swimming above me and if it’s casting a shadow onto me. That’s really
important information to have! This is what life might look like for a Hydra:
they can see light and dark but that’s about it. Now I’m going to build a wall
up around my sensors so that light entering one side casts a shadow on some
of my photo cells. If light enters from the left side of my sensor it casts
light on the right side, if it enters from the top it casts light on the
bottom. I can now use my camera to sense directionality it can see if light is
coming from over there or if there is a predator coming at me from behind this
is what life might look like for flatworms their eyes are just little
sensors in a cup the bigger this wall gets the smaller the hole becomes and
the more directionality I can see eventually I can close that hole almost
all the way until it’s just a pinhole – we call that a pinhole camera. And it’s not
very sensitive so I need to use a lot of really bright lights so that it can
receive an image and since I’m using so many bright lights I have to wear these
glasses to protect my eyes because it’s blinding otherwise so I can’t really see
you guys. But I built this digital camera using 16 photo cells and a pinhole box
and the image you see from it is currently in black and white and it’s
just 16 pixels so it’s pretty extremely low resolution but hopefully you can
make out my selfie. Hi! And the image you see from it is upside down and backwards
because of how light goes through this hole in the front of this camera. The
image is upside down and backwards because, remember if light enters from
the left side it shows up on the right and if it enters from the top it shows
up on the bottom. I can use computer software to rotate and flip that image.
In life that software is stored in brains. It would be good if we had a
colour image and we can do that with a little grade school math
and physics. All of the light we see is made of just three primary colours: red,
green, and blue. Mix them together and you get purple, or well, I mean, you get the
idea. If we specialize our photocells so that each one only detects one colour; say
we cover it with a red filter so that only red light gets onto that one… we can
see how much red is in the image, or how much blue is in the image, or how much
green, too. The thing is that each photocell needs a value for each colour purple
is lots of red, lots of blue, but no green. But we can use the power of averages for
this this photo cell senses red and it uses its neighbour to figure out how much
green and blue is nearby. Computing that we get: purple. our eyes actually work
like this, they have three photo cells called rods
ones four red ones four green and one is for blue. Now my camera it can see colour
so let’s take a look out my window it’s a little pixelated but… I mean okay, it’s
it’s really… it’s really pixelated. After spending a lot of hours trying to
upgrade my camera from sixteen pixels to 81 pixels…
after all that, finally… I gave up when I realized that this was the best possible
image I could get from an 81 pixel camera in the best-case scenario. And yes
it’s cool but it’s just not good enough because I want to show you how lenses
work and I can’t do that with this level of resolution. So, I just upgraded from 16
pixels to over 2 million pixels using one of the camera bodies that I already
owned, and this is the image you get with that and it’s blurry because I still
haven’t added a lens to it. This is still just a pinhole camera it’s a piece of
cardboard with a pinhole in it so the light goes directly onto the sensor. This
is the world through the pinhole eyes of the Nautilus: it’s dark and blurry, but
there are images and colour. For the next step we’re going to add a very simple
lens… Behold! The water droplet. Yes, just a single
droplet of water can act as a magnifying glass, and this is something that you can
try at your own risk on your smartphone. It will act as a macro lens making very
tiny things very large to your sensor so that you can zoom into tiny little
things like the Canadian flag on the sleeve of the astronaut on the
five-dollar Canadian bill. Lots of snails have simple lens eyes like this.
Now that lens is still pretty crude so we’re gonna bring it up to the next
level. This crazy-looking image that’s kind of blown out on the sides is what
you get if you just use a magnifying glass in front of the pinhole. It’s
better than nothing but it’s still kind of distorted on the outside, but
hopefully this gives you an idea of the focus that a piece of glass or our
droplet of water can give you in making an image. I finally look like a real
person! Okay, a weird person but I thats how I normally am. Now there are more
tweaks you could do in evolving a camera, like being able to change the size of
the pinhole, or change the distance between the pinhole and the lens. All of
those things can change and improve the image that you get but I think by now
you should get the idea of how a camera works and how a camera or an eye could
evolve. Something really cool happened while I was working on this project but
before I get into that if you feel like you’ve learned something so far please
consider subscribing to this channel you’ll SEE the button for it below… if
bad puns don’t make you subscribe what will!? ok.. ok. So while this project evolved
the code that I was writing got messier and messier because I kept adding new
code but since it usually wasn’t worth my time to delete the old code that I
was no longer using it kind of just became clutter and just built up. Now,
what’s awesome about that is that that’s what actually happens in evolution. Most
of our DNA doesn’t actually do anything anymore – it used to, but it no longer has
a function, and it just kind of stuck around. Scientists call it ‘junk DNA’ and
it makes up most our DNA! Evolution doesn’t solve things
in the best possible way, it just solves things using whatever way is good enough.
That’s why our eyes have a blind spot. You see, the photocells in our eyes are
actually pointing the wrong way they’re pointing away from light so there’s
actually a bundle of nerves where there should be photocells if you want to
find your blind spot, I left instructions in a link in the description. If you
liked this video you can like this video and if you want to learn more about how
evolution works I recommend the book The Selfish Gene by Richard Dawkins. It’s
actually the reason that I started to take science classes in the first place.
The 40th anniversary of the book just came out and I can tell you it stands
the test of time, it is a true classic. You can buy that book using the link in
the description and that link will also help support this channel the Scope of
Science. I also put some links to the camera gear that I use to film the
camera that I made it was meta, right? Anyways thanks so much for watching!


I try to build a camera using evolution, starting with a penny. For Science!

Support me on Patreon!

The Selfish Gene by Richard Dawkins:
My primary camera:
Macro Lens (for shots like the eye):

How to find your blindspot:—and-how-to-find-yours

I’m on social media!

Creationists and other evolution deniers often ask how the human eye, in all its complexity, could have possibly evolved. How does something so complicated just happen due to random events? Well, I think the part that people are missing about this case of evolution is that every step along the way is still useful for animals, it contributes to their survival.

In this video I demonstrate that process, and starting with a penny, I create photocells, sensors, cameras, and lenses, as I evolve a digital eye one step at a time. I could have done this in an even more gradual process, to emulate biology even more closely, but i think this is just as illustrative and keeps things under 10 minutes.

I built this with an arduino, some photo-resistors, some resistors, and otherwise pretty basic components that I had lying around my house. Funny enough, this project actually evolved out of wanting to make a video about weird quirks related to the human eye (our blindspot is only one of them), and then eventually somehow it ended up being a video about building a camera. Evolution!

#Evolution #HumanEye

Author: dhobson