What is inside a digital camera? (1 of 2)
In this video we go inside the digital camera to discover what is inside and how it works. Created by Karl Wendt.
Want to join the conversation?
- Why is the CPU under that blob? What is the blob made of?(33 votes)
- The blob is made of epoxy. The epoxy protects the connections to the CPU from impact and moisture.(44 votes)
- What is a diode?(37 votes)
- He talks more about it in 'what is in a tap light?' I hope that answers your question.(4 votes)
- How does the image that comes in through the lens and hits the plastic turn into 1's and 0's?(13 votes)
- Different formats (like jpg and png) handle this differently, but the camera is able to take the information on a pixel-by-pixel basis (sometimes this isn't the case on cheaper models) and convert it to a simple binary code based on the amount of red, green, and blue detected (I'm pretty sure it's in that order most of the time, too).
The image itself is all those pixel codes put together in order. That order depends on the format. If I recall correctly, png does it line by line, while jpg does it in clusters.(12 votes)
- How does a diode work exactly?(8 votes)
- It is made from semiconductor material like silicone that has been treated to contain a surplus (negative) electrical charge on one side and a lack (positive) on the other.
Where the two materials meet, the negative and positive charges switch places in order to balance things out, but when that has happened, the current stops flowing through the diode so well.
In order to allow the current to flow, you need to apply positive charge to the positive side, negative to the negative side (think of how batteries have + and - ends). The build up of same charge on each side increases the pressure on the meeting point between the two layers of the diode and allows the barrier of exchanged electric charge to be overwhelmed, so the diode begins to conduct well again.
If positive charge is applied to the negative side (and negative to the positive, i.e. if you were to attach a battery the other way round, it would only reinforce the barrier that has formed where the two layers of the diode meet.(15 votes)
- are quartz in all digital cameras?(6 votes)
- quartz are in all digital stuff, it's more than "counting time", it's used to synchronize different parts of the ICs(6 votes)
- Dr. Wendt, do you put this stuff back together when you're done?(5 votes)
- How does a Liquid Crystal display work?(3 votes)
- an LCD is technically different from a TFT (which is on the back of the camera) but here's the principle of operation
The LCD works by polarizing molecules and obscuring parts of the glass they are under. so LCDs are not directly visible if there is no ambient light (think old digital watches - if you're in a dark room, unless you shine a light on the display, you can;t see it)
The TFT matrix is always illuminated from the back usually by CCLs. The TFT matrix consists of lots and lots of thin light filters that only let certain ligth pass through them. The LCD matrix is placed under those light filter and it either obscures or lets the light through. This way a color image is created.
- light emitting diode? an electronic component that emits light as current is passed through it.(1 vote)
- What are inside chips? How do they work and store memory?(2 votes)
- That is a very complicated question. You should try books and the internet(I recommend inside the processor(2 votes)
- At2:20, what would have happened if he put the batteries in and took a picture? Would the camera function or not?(2 votes)
- [Karl Voiceover] Okay, so here's our Vivitar ViviCam Camera, and we're gonna take it apart and show you how it works. We got the batteries here, and there's the on switch, and now that we have the camera on we're going to take a few photos. You can see the LCD display is showing what's going on there, and letting us see the pictures. Now the LCD is backlit with an LED, which is, LCD stands for liquid crystal display, and LED stands for light emitting diode. So, let's go ahead and get crackin', we'll take it apart. We'll take all the screws out that are holding the two halves of the camera together. So we'll remove the top part, and that's likely made out of ABS, and there's a electroplated bezel, that surrounds the lens of the camera, it's screwed in place. And that's also probably ABS, plated ABS. And now let's go and take a look at what the camera's latch looks like and what it's made out of. We've got some, looks like chrome-plated stamped steel, connected to a spring, and that feeds the electricity from the underside of the back side of the batteries, to the board, and so that's where the positive connection on the board is, and the negative connection is up at the top. So we're gonna remove the pin and we can take the latch out now. Now you can slide the latch back and forth, you can see how it moves. Again this is plated steel, you can see there's four little connections on there, we'll talk about those in a second, but let's remove this back piece. This is just a simple insert, and I think it's probably heat staked in place. What that means is really low-cost way to attach things. This metal piece is as well, you can see those four points there. They're heat staked in and it is magnetic, so it's plated steel. And so, now we're gonna remove these screws that are connecting the plastic bezel that surrounds the camera and connects the two sides. And so you can see, it's just an injection molded piece, and I believe that that material is ABS, but again it didn't have a plastic designation on it, so it's not 100%, could be polypropylene or maybe styrene. Probably styrene. So there's the on button and the off button, I should say, the on button and the shutter button, and they push down and trigger the membrane switches, which are mounted on our printed circuit board, or a piece of the printed circuit board that's connected. So now let's take out the screws that are holding the board in place. And we tried to remove the screws for our tripod mount, but one of them is stripped, so we're just going to leave it in place. And I think we'll just pop the back out there and we'll take a look at the two switch covers. These switches are injection molded and then they are painted, and then heat staked in place. And so you can see the silver colors from the paint, and the heat stake process is basically the plastic, just a little tab at the end of the plastic is melted against the outer part of the housing. And again, it's just a really low-cost way to hold the switches in place, and keep them above their membrane switches. So you can see which ones go with which, these are the, that's the on/off switch, and this is the selector button. These selector buttons allow you to scroll through pictures, and then we have a menu and a play button. So this is our step by step of what happens when you take a photo. The first thing that happens is the lens right here collects some light. So let's take a look at how that happens. So the light's going to come down from the sun, hit Billy, reflect off of him, go in through the lens, get focused on our image sensor, and when it does that, it's going to pass through these two filters. And at this point, photons are what's conveying the information. So it's just a reflected light that's conveying the information to our image sensors. So it's going through the lens, and our filters. And so we have an infrared filter here, and the infrared filter is, basically helps to, it keeps the infrared out, and that can effect the image. We also have a bare color filter. The bare color filter is right on top of the image sensor, and it basically breaks the sensor up into what looks like a checkerboard of red, green, and blue, and there's twice as many green as there is red and blue, because our eyes are more sensitive to some colors than to others. And so, the bare filter allows us to get color information from our image sensor. So there's two types of image sensors; there's the CCD, or charge coupled device, and a CMOS, a complimentary metal oxide semiconductor. Now the CCD tends to have less noise than the CMOS, and it tends to be a little bit more expensive, and the components for doing the analogue processing are not mounted on the board, they're usually not on the board, they're off of the board. Now the CMOS has the components that some of the transistors for doing the analogue processing on the board, and so the CMOS tends to be a lot less expensive, it also tends to take a lot less power, and it tends to have more noise, so the image quality tends to be less. But again, there are exceptions, if you get a really expensive CMOS chip or really inexpensive CCD, this information may not apply, these are just sort of general guidelines. So the light hits the image sensor, and it is converted into analog electrical signals, those electrical signals are sent to a digital to analogue converter, and then the digital signals, you can see those represented by the ones and zeroes, are sent to the digital image processor. So the digital image processor on this particular camera is underneath the screen. It's represented, well, it's underneath the black blob, too, the black blob is actually epoxy and it's put on the board as kind of a low-cost way to protect the processor. And so, anyway, the processors involved in the mosaicing, which means that it takes the information from that was created by the color filter, and the individual pixels, and it averages those to create a smoother image, and it uses a software algorithm to do that. And you can see that there's a little hair that's represented there in the super zoomed-in view of Billy. Okay, and it can also be used for JPEG conversion and other things. So the memory buffer on our camera is on the other side here, you can see it, it's right there, it's the big chip. And the memory buffer takes the images and stores them before they're sent to the memory card controller, or the octal latch here, and that basically acts as like the traffic control for the data going to the flash memory. And so, the flash memory is this chip right here, and the flash memory is where all the data is stored on this particular camera. Now most cameras have detachable flash memory, this one, it's built in. And that's probably because it was cheaper than buying a connector. So the LCD display you can see is right there, and that's what displays the image. And then there's our USB connector. And of course you can hook a wire and connect that to the computer and then print out the images as well, that's another way of getting your final image. Go look at some other components; this is the speaker. It's a piezo speaker, and it produces a high frequency sound when you push the buttons. And that just gives you some auditory feedback to let you know that the button has been successfully depressed. And the board itself is made out of a cloth laminate material. And so if you look at the other components on the board, let's see, there's an LED here, and another one here, and those LEDS indicate both when the camera is on, and also when a photo has been taken. So let's take a look on this side of the board, there's a little silver device, and that's a quartz timer. And the timer helps to synchronize all the functions on the board. It's used by the microprocessor to do that. You can see the resistors and capacitors here, the resistors are usually denoted by the R and the capacitors by the C. And they can be used together to both filter noise, have an influence on some of the timing functions, they can also be used to protect various circuits on the board, and various components. So these components here are power components, and they take the power from the battery and make it more usable for the camera. And you can see the traces here, the whole top of the board is covered in copper, and then the copper is etched away in the places that you don't need wire connections. So the wire connections are made with copper that's left, and you can have connections between all the different components there on the board. So we're gonna open up our screen and see what's on the inside. So on the inside of the screen, there is a LED and a die resistor, and the resistor protects the LED, and you've got a clear piece of plastic and then a white reflector in the back, and then there's a white diffuser, it's a thin piece of plastic right here. And these pieces, and then there's also a reflective part to the screen. And these pieces are all designed to sort of bounce the light around and help to diffuse evenly since there's only point of light created by that LED. You want to make sure that the image is evenly lit on the back. And the LCD display is in the top and it's sandwiched between two pieces of glass, and those pieces of glass have the liquid crystals inside, and you can sort of see that by the smoky color there, you can see through it just a little bit. And they light up, or I should say, they turn different colors and are lighted by the LED behind them, to display the image when you take a picture, or when you go through your images. Thanks to everybody who provided constructive feedback on the previous video. We're always looking for ways to improve.