Lamp from the scanner connection. Security Information Portal

The design of absolutely any device, especially if it (the device) includes both electronic and mechanical elements, may seem to an uninformed person a storehouse of secrets and mysteries, which, oh, how difficult it is to figure it out on your own. Flatbed scanners are just such an option. At first glance, the scanner device does not seem particularly complicated: a body with a few connectors and a couple of buttons, a removable tablet cover, and a glass on which originals are placed for scanning. But here's how the "economy" works, and what the numbers of its specification mean - this, as they say, is a completely different song. To learn how to navigate the numerous models of scanners on the computer market today, you need to imagine the real value of the characteristics indicated by the manufacturers. But to make this article more informative, we will analyze the design of the scanner, as they say, in the literal sense of the word, "we will analyze it."
Let's start, perhaps, with the most important element of any scanner - a photosensitive matrix, which is, as it were, its "eyes".

Matrix

Yes. It is the matrix that is the most important part of any scanner. The matrix transforms changes in the color and brightness of the received light flux into analog electrical signals that will be understood only by its only electronic friend - an analog-to-digital converter (ADC). From this point of view, the ADC can be compared to a guide-interpreter, her constant companion. Only he, like no one else, understands the matrix, because no processors or controllers will parse its analog signals without preliminary interpretation by the converter. Only he is able to provide work for all his digital colleagues who perceive only one language - the language of zeros and ones. On the other hand, you can take any processor, converter or amplifier, illuminate them with the brightest light source and wait for any reaction for so long until you get bored. The result is known in advance - it will be zero, because no other electronic components of the scanner are sensitive to it. If you like, they are all blind from birth. Another thing is the matrix. The luminous flux, falling on its surface, literally "knocks out" electrons from its sensitive cells. And the brighter the light, the more electrons will be in the storage of the matrix, the greater will be their strength when they rush to the exit in a continuous stream. However, the strength of the electron current is so incommensurably small that even the most sensitive ADC is unlikely to "hear" them. That is why, at the exit from the matrix, an amplifier awaits them, which is comparable to a huge mouthpiece, which, figuratively speaking, turns even a mosquito squeak into a howl of a loud siren. Enhanced signal(still analog) will "weigh" the transducer, and assign each electron a digital value, according to its current strength. And then ... Further, the electrons will be digital information, the processing of which will be handled by other specialists. The work on recreating the image no longer requires the assistance of the matrix.
But let's leave the general discussion. Let's look at the practical side of things. Most modern scanners for home and office are based on two types of matrices: CCD (Charge Coupled Device) or CIS (Contact Image Sensor). This fact raises two questions in the minds of users: what is the difference and which is better? If the difference is noticeable even to the naked eye - the body of a CIS scanner is flat compared to a similar CCD device (its height is usually about 40-50 mm), then answering the second question is much more difficult. The answer here needs to be argued in order to avoid an avalanche of generated questions like "how is it better?", "Why is it better?".
First, let's look at the main advantages and disadvantages of these two classes of scanners. For convenience, I reduced them to a small table:


The CCD scanner has a greater depth of field than its CIS counterpart. This is achieved through the use of a lens and a system of mirrors in its design.

In the figure, for ease of perception, only one mirror is drawn,
while a typical scanner has at least three or four

CCD scanners are much more common than CIS scanners. This can be explained by the fact that in most cases scanners are purchased not only for digitizing sheet text documents but also for scanning photographs and color images. In this regard, the user wants to get a scan with the most accurate and reliable color reproduction, and in terms of light sensitivity, a CCD scanner transmits color shades, highlights, and halftones much more strictly than a CIS scanner. I note that the error in the spread of the levels of color shades distinguished by standard CCD scanners is about ± 20%, while for CIS devices this error is already ± 40%.

Schematic representation of a CIS sensor

The CIS-matrix consists of an LED strip that illuminates the surface of the scanned original, self-focusing microlenses and the sensors themselves. The sensor design is very compact, so a scanner that uses a contact sensor will always be much thinner than its CCD counterpart. In addition, such devices are famous for their low power consumption; they are practically insensitive to mechanical influences. However, CIS scanners are somewhat limited in their use: devices, as a rule, are not adapted to work with slide modules and automatic document feeders.
Due to the peculiarities of the technology, the CIS-matrix has a relatively small depth of field. For comparison, CCD scanners have a depth of field of ±30 mm, while CIS scanners have a depth of field of ±3 mm. In other words, putting a thick book on the tablet of such a scanner, you will get a scan with a blurred stripe in the middle, i.e. where the original is not in contact with the glass. With a CCD device, the whole picture will be sharp, since its design has a system of mirrors and a focusing lens. In turn, it is the rather bulky optical system that does not allow the CCD scanner to reach the same compact dimensions as the CIS counterpart. However, on the other hand, it is the optics that provide the obvious gain in quality. I note that the requirements for optics are very high, so the rumors that some models of scanners use, de, "plastic mirrors" are greatly exaggerated, if not "fictional". ;)
In terms of resolution, CIS scanners are also not a competitor to CCDs. Already, some models of CCD scanners for home and office have an optical resolution of about 3200 dpi, while CIS devices have a limited optical resolution, if I'm not mistaken, so far 1200 dpi. But, in general, it is not worth throwing CIS technology off the shields. All technologies are developing rapidly. Scanners with a CIS matrix have found their application where it is required to digitize not books, but sheet originals. The fact that these scanners are completely USB-powered and do not need an additional power source, came in handy for owners of portable computers. They can digitize the original and translate it into a text file anywhere, without being tied to proximity electrical networks, which allows you to close your eyes to a number of shortcomings of the contact sensor. Actually, therefore, you can answer the question "which scanner is better" based on your specific requests.

The most important element of the scanner is the CCD matrix

In the photo above, you see a CCD that appears to be a "big chip" with a glass window. It is here that the light reflected from the original is focused. The matrix does not stop working all the time while the carriage with the scanning carriage, driven by a stepper motor, travels from the beginning of the tablet to its end. I note that the total distance of the carriage movement in the "Y" direction is called the sampling frequency or the mechanical resolution of the scanner (we will talk about this a little later). In one step, the matrix completely captures horizontal line tablet, which is called a raster line. After the time sufficient to process one such line, the carriage of the scanning unit moves a small step, and it is the turn to scan the next line, and so on.

Side view of the CCD-matrix

In the side view, you can see two ordinary screws that play a "delicate" role." printed circuit board in the top view), so that the reflected light from the mirrors falling on it would fall evenly over its entire surface. By the way, if one of the elements of the optical system is skewed, the image recreated by the computer will turn out to be "striped".

Enlarged image of part of the CCD sensor (Macro
taken with Canon EOS D60 digital camera)

The enlarged photo of the CCD-matrix clearly shows that the CCD-matrix is ​​equipped with its own RGB filter. It is he who represents the main element of the color separation system, which many people talk about, but few people know how it actually works. Typically, many reviewers limit themselves to the standard wording: "a standard flatbed scanner uses a light source, a color separation system, and a charge-coupled device (CCD) to collect optical information about the object being scanned." In fact, light can be divided into its color components and then focused on the matrix filters. An equally important element of the color separation system is the scanner lens.

The scanner lens is actually not as big as it looks on
Photo

Frame

The body of the scanner must be sufficiently rigid to avoid possible distortions of the structure. Of course, it is best if the base of the scanner is a metal chassis. However, the bodies of most home and office scanners manufactured today are made entirely of plastic to keep costs down. In this case, the necessary structural strength is provided by stiffeners, which can be compared with the ribs and spars of an aircraft.

Location of the main functional units of the scanner

An important element of the housing is a transport lock, the presence of which is designed to protect the scanning carriage from damage during the transportation of the scanner. It must be remembered that before turning on any scanner equipped with such a latch, you need to unlock it. AT otherwise, the mechanism of the machine may be damaged. In principle, manufacturers focus buyers' attention on this small nuance with bright stickers with appropriate warnings.
Some people think that the body cannot affect the quality of the scan in any way. However, this is not the case. The fact is that the optical system of the scanner does not tolerate dust, so the body of the device must be sealed, without any cracks (even technological ones). More than once I came across models that did not meet such requirements. If you are going to buy a scanner, then I would recommend paying attention to this.
Also, when buying a scanner, pay attention to the possibility of detaching the tablet cover. This feature of the machine is especially useful when scanning originals such as thick books or magazines.
The edges of the flatbed should have a gentle slope - this makes it easier to quickly remove the original from the glass. In addition, there should not be any gap between the glass and the tablet that would prevent the original from being removed. Also pay attention to the presence of markings around the perimeter of the tablet.

Control block

All scanners are controlled from a personal computer to which they are connected, and the necessary settings before scanning are set in the user window of the control program. For this reason, scanners for home and office do not necessarily have their own control unit. However, many manufacturers go to meet the most unprepared users, and install (usually on the front panel) a few "quick scan" buttons.

Quick scan buttons - an element you can do without

In the photo above, you can see that each button corresponds to a specific icon. Generic Functions quick start usually involve starting a standard scan operation, outputting to a printer, and then sending it to e-mail, fax, etc. It is clear that specific parameters of the scan quality are set for one or another button. However, pressing one or another button first leads to the launch on the computer of the application (if there are several) that is responsible for the called operation. I note that not all SOHO scanners are equipped with their own control unit, and professional devices lack such elements even more so.
Some manufacturers "sin" by excluding from the scanner driver a number of settings that, in their opinion, most ordinary users do not use. So, for example, Hewlett-Packard SOHO scanners lack the ability to change gamma correction, load ICC profiles, and much more. But it is Hewlett-Packard, like no one else, who likes to "pamper" users with a number of quick scan buttons.

About light sources

Absolutely every scanner uses its own illuminator. This is the name of a small and powerful module, the task of which is to turn on and off the scanner lamp (or whatever replaces this lamp). In CIS scanners, an LED bar is used as light sources, due to which this class of devices consumes so little energy.
In CCD scanners, originals are normally illuminated by Fluorescent Lamp with a cold cathode. Its light is thousands of times brighter than LEDs. But in order to cause the glow of the gas inside the lamp, you need to apply a very high voltage. It is produced by a separate unit called an inverter.

The high voltage module is required to power the lamp

The inverter increases the voltage from five volts to several kilovolts, and also converts direct current into alternating current.

In general, there are three main types of lamps used in scanners:

xenon gas discharge lamp (Xenon Gas Discharge);
fluorescent lamp with a hot cathode (Hot Cathode Fluorescent);
cold cathode fluorescent lamp (Cold Cathode Fluorescent)

However, scanners for home and office use only cold cathode lamps for a number of reasons.

Cold cathode lamp

The scanner lamp is mounted on the plastic chassis of the scanning carriage directly above the reflector. The reflector itself has the form of a reflector (an effective "collector" and reflector of light) in the form of a magnifying mirror. The light from it is amplified to brightly illuminate the object on the tablet. Reflected from the original on the glass, the light passes through the slit of the chassis (I highlighted its outline in blue in the photo) and is received by the first, longest mirror of the optical system.
Among obvious benefits cold cathode lamps can be noted for a long service life, which is 5,000 - 10,000 hours. For this reason, by the way, some scanners do not turn off the lamp after the scan is completed. In addition, the lamps do not require any additional cooling and are very cheap to manufacture. Of the shortcomings, I note a very slow inclusion. Typical lamp warm-up time is 30 seconds to several minutes.
The lamp has an important effect on the scan result. Even with a slight difference in the characteristics of the light source, the light flux reflected from the original incident on the receiving matrix also changes. This is partly why you need such a long warm-up time of the lamp before scanning. I note that some drivers allow you to reduce the warm-up time if the quality of digitization is not so important (for example, when scanning text information). I will add, in order to somehow compensate for the loss of lamp characteristics (and this inevitably happens during long-term operation of the device), scanners automatically perform a self-calibration procedure using a black-and-white target located inside the case.

The photograph clearly shows how, under the influence of light over
time, the housing plastic and the calibration target tarnish

The scanner under study is no exception. The photo above clearly shows the color target, according to which the scanner adjusts the colors before scanning, compensating for the "aging" of the lamp. Here you can also see that with the passage of time, not only the internal plastic, permanently illuminated by the lamp, but also the calibration target itself fades. This, in turn, leads to color fade and increased color distortion.

A cold cathode lamp is somewhat similar to a fluorescent lamp.
light ... only a small


If desired, from an inverter and a cold cathode lamp, you can
build a table lamp

In the photo you see the misuse of the scanner lamp. ;) The inverter module was connected to the standard computer block power supply, for which wires with an adapter were soldered to its board. In principle, if some kind of holder is adapted here, it will come out pretty good and bright desk lamp.

ADC operation

Who helps the scanner processor "find a common language" with the matrix? Of course, the analog-to-digital converter involved in the translation analog signals into digital form. This interesting process can be represented as follows. First, the ADC sort of "weighs" the input voltage, like a store clerk picking up a set of standard weights of the same weight as the product. Then, when the voltage is measured, the ADC presents the data to its "boss", that is, the processor, but in the form of numbers. And as a result, everyone is happy.
You can imagine yourself as a processor and ask what happens at the output of the ADC when the input voltage changes? Let's give, for example, 4 Volts to the input of the converter, then 9 Volts. The following variations of numbers will appear at its output: first 00000100, then 00001001. In binary code, these are numbers 4 and 9. The number of zeros and ones with which the ADC expresses the measured value is its bit depth, which is measured in bits. A setting such as converter capacity is extremely important for the scanner, because it characterizes the accuracy of the measurement of the input signal.
Today, on store shelves, you can see inexpensive scanners that use converters with a bit depth from 24 to 48 bits. Theoretically, it is always better to choose a scanner that has more bit depth. In this case, one subtlety should be taken into account: sometimes manufacturers write "48 bit" in large letters on the boxes, and somewhere in the corner they specify in small print: "software 48 bit, hardware 36 bit". This means that a large beautiful figure has nothing to do with the accuracy of the ADC installed in the scanner, and the real bit depth in this case is 36 bits. That is what you should be aiming for. It should be recognized that in home practice, the differences between the results of 36-bit and 42-bit scanners are almost imperceptible (the human eye is able to distinguish about 24 bits of color shades, i.e. about 16.7 million). In our case, the bit depth of the converter and the color depth are one and the same. After all, the converter calculates nothing more than the colors of the dots that make up the image. The greater the bit depth of the converter, the more reliably the scanner can convey the color of each point of the image. Accordingly, the more the image will resemble the original.

CPU

Modern scanners are equipped with specialized processors. The tasks of such a processor include coordinating the actions of all circuits and nodes, as well as generating image data for transmission. personal computer. In some scanner models, the processor is also assigned the functions of an interface controller.
List program instructions for the processor is stored in a permanent memory chip. Data is written to this chip by the scanner manufacturer at the production stage. The contents of the chip are called "firmware" or "firmware". Some professional scanners have the ability to upgrade, but low-cost home and office models usually don't.
In addition to a permanent memory chip, scanners also use RAM, which plays the role of a buffer (its typical values ​​are 1 or 2 MB). Scanned information is sent here, which is almost immediately transferred to a PC. After sending the contents from memory to a personal computer, the processor resets the buffer to form a new message. I note that the instructions for the processor are also entered in the cells random access memory, but already the processor itself (for this it is equipped with several kilobytes of its own "RAM"). The organization of its memory is built on the principle of a pipeline, i.e. after executing the first instruction in the queue, the second one takes its place, and the last one - new instruction.
The amount of scanner RAM was previously indicated by manufacturers in technical specifications scanners. However, since this parameter practically does not affect the performance of the device; in modern scanners it is often silent. It is also silent if a particular scanner uses a certain area of ​​the computer's RAM, which is implemented by the driver.

interface controller

The interface controller is responsible for the exchange of information and commands between the scanner and the computer. As I noted above, this microcircuit may be absent if the processor has an integrated controller module. In the era of "kopeck pieces" and "three pieces" scanners were produced with SCSI, IEEE1284 (LPT) and even RS-232 interfaces. Today's range of SOHO scanners is limited to USB, FireWire and SCSI interfaces. At one time, there were rumors about the appearance of Bluetooth scanners, but so far things have not gone further than rumors. It is clear that in devices with different interfaces installed the same different controllers. They are not compatible with each other, because they "speak different languages."

In our case, the interface board combines SCSI and USB ports, as well as
has two slots for connecting additional modules

SCSI (Small Computer Systems Interface)

Scanners with SCSI interface were most common a few years ago. It must be admitted that the era of SCSI scanners is coming (or has already come) to an end. The main reason is the emergence of high-speed USB interfaces and FireWire, which require neither special delicacy when connecting, nor additional adapters. Among the advantages of the SCSI interface are its high bandwidth, as well as the ability to connect up to seven various devices for one tire. Of the main disadvantages of SCSI - high cost organization of the interface and the need to use an additional controller.

USB (Universal Serial Bus)

The USB interface has become the most widely used due to its integration into all modern motherboards as the main connector for peripheral devices. Today, the vast majority of home scanners come with a USB interface. In addition, a group of CIS scanners receives the necessary power from the USB port, which attracts owners of portable computers. Agree, you cannot realize such quality by means of SCSI.

FireWire (IEEE1394)

When choosing a connection type, at least for me, the FireWire interface is more preferable. FireWire is a high-speed serial I/O interface that differs from USB in that it does not require a host controller to provide a connection. The organization of its work is carried out according to the peer-to-peer scheme. Actually due to this, a lower (in comparison with USB) CPU load is achieved.
Will see the light soon peripherals with a new modification of this interface - FireWire 800 (IEEE1394b). That's when it will become the fastest among the peripheral standards that have ever been developed.

broaching mechanism

The main moving module of the scanner is its scanning carriage. It includes an optical unit, with a system of lenses and mirrors, a photosensitive matrix, a cold cathode lamp (if it is a CCD scanner) and an inverter board. To the scanning carriage is rigidly fixed toothed lingering belt, which sets in motion the stepper motor of the device.

Location of the belt attachment to the scanning carriage



Elements of the broaching mechanism

A special tension spring, which is put directly on it, is responsible for the tight contact of the belt with the gears. The carriage with the scanning carriage moves along the guide sled, along the body of the device (see photo).

Engine

stepper motor

The Step Motor can turn the spindle in both directions in very small increments. Because of this feature, it is always possible to move the scanner carriage a strictly defined distance. Such an engine is in every flatbed scanner. It rotates the gearbox (the gears you see in the photo) and drives the carriage, which contains the optical unit, lamp, and matrix. A special microcircuit, the motor controller, is responsible for choosing the direction and speed of rotation. The accuracy of carriage movement is called mechanical resolution in the "Y" direction (Y-direction).

The optical resolution of the scanner is the X direction, and its
mechanical resolution - Y direction

In general, optical resolution is determined by the number of matrix line elements divided by the width of the working area. Mechanical - the number of steps of the scanning carriage in the direction of movement Y. In the specifications for scanners, you can find designations such as "600x1200". Here the second digit is the mechanical resolution, while the first characterizes the optical resolution of the scanner. There is also an interpolated resolution, which is sometimes several orders of magnitude greater than the optical resolution, but does not depend on the physical equipment of the device. I would call it "zoom resolution". Interpolation functions (enlargement of the original image) are performed by software scanner. The value of the interpolation values ​​indicated by the manufacturers is doubtful - any image can be enlarged with the same success using Photoshop.

Engine internals



Reducer

The motor core is connected from the outside by a gear train, which is a simple gearbox. Its large gear extends the strap to which the scanning carriage is attached.

Power Supply

Scanner power supply

Home or office scanners do not consume too much power from the network, so SOHO devices cannot be found in power supplies powerful elements. The internal power supply of the device considered in this article produces voltages of 24 Volts / 0.69 A, 12 Volts / 0.15 A and 5 Volts / 1 A. for a light source - a lamp with a cold cathode, a high voltage of several kilovolts is required, a separate unit, which I talked about a little higher, is responsible for its power supply.

Additional devices

For many flatbed scanners related accessories are available, in most cases purchased separately. Of these, we can note the automatic document feeder and the adapter for scanning transparent originals (slide adapter).

The scanner with automatic document feeder is a bulky
construction

The Automatic Paper Feeder is required when you have to scan many standard size print sheets. Making sure your scanner can connect the ADF is easy enough. To do this, you can simply look at the connection panel and make sure there is an ADF (Automatic Document Feeder) socket. Note that the automatic document feeder is always "linked" to specific model scanner, or to a series of models. There is no universal feeder! The reason is that this device controlled from the scanner interface board. It is clear that the feeder cannot work without communication with the scanner, so when buying, be careful and make sure that your scanner supports the specific ADF.

View of the transparent window of the automatic document feeder from the other
side glass

The automatic feeder works as follows. After the auto-calibration and readiness phase, the scanner positions the carriage in front of the transparent ADF window. Then, sheet originals are taken one by one from its input tray, and when passing through the designated window, they are digitized.
The slide adapter is an accessory designed to digitize transparent originals (films, slides, and negatives). There are two types of such adapters: passive, which uses the scanner's lamp, and active, which shines through a transparent original with its own lamp.
The Active Slide Adapter has its own light source that shines through the transparent original. Some models of such slide adapters have a movable carriage with a light source, which is driven by a motor and a pulling mechanism. The light source moves along the guide, according to the positioning of the scanner carriage. The scanner's own lamp turns off. Today, scanner models for home and office without moving parts in the slide adapter module are more common. A typical example is the recently tested EPSON Perfection 3200 Photo by our test lab. Its light source is built into the scanner cover and occupies its entire useful surface. To match the adapter with the scanner, a wire with a connector comes out of the cover, which connects to a special socket on the back of the device (it is denoted by the abbreviation XPA). The adapter lamp is activated automatically when the original type is changed in the control program, which is additionally indicated by the indicator in the scanner cover. Transparency originals are installed in the included templates that support: 12-frame 35mm film strip, four 35mm framed slides, 120/220 (6 x 9 cm) / 4 x 5" transparencies. Well, the templates themselves are placed on the scanner glass. During scanning, a stream of light passes through a transparent original, and when it enters the scanner's optical system, it is processed in the same way (as an opaque original). It is clear that such scanner properties as optical resolution and depth of light do not change when using a slide adapter, which cannot be said about the range of optical densities. This scanner parameter directly depends on the brightness of the light source and the exposure time. You can imagine it like this: the darker the original, the less light it transmits, the longer it takes for the CCD-matrix drives to collect the required amount of charge. The darkest of the transparent originals are x-ray films (up to 3.6D). To get a high-quality scan from them, you need a bright light source. However, the range of reproducible optical densities of the scanner is by no means determined only by the brightness of the lamp. It mainly depends on the bit depth (or accuracy) of the analog-to-digital converter, the quality of the optical system and the capabilities of the photosensitive matrix.
The passive slide module is simpler than the active one. This adapter uses the lamp of the scanner itself as a light source. The intensity of the light flux in this case is significantly lower than in the case of an active adapter. Accordingly, the quality of scanned images is also lower, which is quite acceptable, for example, for the Web. Passive slide adapters are also inexpensive.

Conclusion

In general, about the scanner, as about the most difficult electronic device you can talk for a long time, but still within the framework of one article it is impossible to convey all the interesting nuances. Today we found out the following: for what reasons CCD scanners digitize originals much better than devices with a contact sensor; why the bit depth of the converter is important, and how the optical resolution differs from the mechanical one; what are the light sources and how they affect the quality of the scan; how the electronic and mechanical parts of the scanner interact, and why slide adapters are not suitable for all devices. In general, I tried to tell about the features of modern SOHO scanners in the most accessible form, and I would be interested to know your opinion about this article.

Not inferior in its effectiveness to serious industrial analogues. Now let's move on to the device circuit itself, the basis of which is made on the AT89C52 microcontroller.

Explanations for the scheme:

• - JP1 - DMX.
• - JP2 - DMX/music switch.
• - JP3 - microphone (observe polarity).
• - JP4 - variable resistor 50-100 kOhm, microphone sensitivity control.
• - JP5 - food. I used ~10V to get +14V to the motors.
• - JP6, JP7 - connection of optical sensors of zero position of gobo circles and color. A slot is made in the circles, along which the circle stops.

JP8 - strobo drive control. For me, this output goes to a transistor, which, through an optocoupler and a triac, controls the extinguishing of the lamp. That is, there is no signal - the lamp is off, there is a signal - the lamp is on). Here is the control scheme:

The triac controls the electronic power supply. It was 12V 200W.

I converted it to 15 V and used a lamp with a reflector from medical devices 15 V 150 W. There is a thermistor (NTC1) in series with the lamp so that the lamp lights up smoothly and does not burn out.In the music mode, this node does not work and the lamp is constantly on. This board is fixed on a piece of textolite and screwed right under the lamp:

• - JP9 - optical prism control. An engine is installed, which, with a signal at this output, spins and rotates the optical prism, which bifurcates or detunes the image).
• - JP10 - JP11 - connection of stepper motors - 2 mirror control, gobo circle and color circle.
• - JP12, JP13 - connector for in-circuit programming.

Firmware for MK and source code is possible. Other files - on the forum. Photos of the light scanner board on the microcontroller AT89C52:

Gobo circles and colors are stopped by an optical sensor. The circle spins in the slot of the optosensor. when a slot in the circle passes through the opto-sensor, it stops. The mirror position motors, after turning on, deflect it to the extreme position, hit against the stop and stop. Then they turn to a certain angle in opposite direction- this is the middle position of the mirror.

I bought a gobo circle without dichroic filters. However, I could not use the ready-made ones, since the angle of rotation did not converge. Therefore, I made circles from thin aluminum for my diameter and my angle of rotation. I drilled holes of the required diameter (slightly larger than the purchased gobos).

To start, a little introduction.

Once it was time to clean up at work, to clear the rubble of old boxes from under monitors, printers, cases, etc. And sorting out these blockages, two old UMAX 1200S scanners and, in my opinion, 600S, caught my eye.
And the time has come to mock them, as they once mocked me.

Having quickly dismantled the first 1200, I took out everything more or less useful from there, namely: a red-hot pin along which the scanner complex with a lamp traveled, a microcircuit and the scanning sensor itself with a system of mirrors. Having taken out all the giblets, I decided to figure out what was valuable there. I don’t know the technologies of those years, but the scanning sensor turned out to be gilded both outside and inside. Gold did not seduce me, the analysis of the scanner continued.
In addition to the mirror systems in the main moving part of the scanner and the lens, there was a lamp very similar to a lamp daylight but only a few millimeters thick.

A power circuit was connected to the lamp, from which two wires departed on the connector, which greatly tempted me to connect it to some kind of source direct current. Fortunately, in the previous box there were several power supplies from switches, monitors, and FIG knows what else.

Having sorted out all the rubbish and throwing out the excess, I proceeded to the tests.

To begin with, a 5 volt and 2 amp power supply was selected. When I connected the lamp, I saw that it caught fire, but not completely. A few cm at the far end of the lamp were dark. It's time for 9 volt block supply with 2.2 amps. (the one above)
At the same time, the lamp lit up quite brightly and completely.

Knowing that the scanner worked from a 12v 2a power supply and, knowing the hot nature of the lamp, as well as the fact that it is not intended for permanent job, I didn't pick b.p. more power, especially since the brightness was enough for me.

And so, having come home, I found a use for these lamps - to illuminate the space under the table.

For a long time I was annoyed by the fact that under the table, crawling to the computer, I had to take a flashlight and at the same time there were several problems both with the batteries for it, and with the fact that one hand is busy and I need to be distracted, watching where the flashlight shines. It was decided to hang the lamp under the table, mark the place and lay out the tools.

It turned out to be very convenient that the regular lamp reflector from the scanner was removable and with its own mount.

The time has come to create a box for the lamp power circuit, so as not to hang naked and ugly. To do this, we took poster white plastic 6 mm thick and the bottom blank blank from a reel with blanks.

From the tools it took: Dremel with a cutting disc, a round file, two small drills (in my case for a hexagon), a paper cutter with interchangeable blades, a soldering iron and screwdrivers.

From the available was: a connector for the desired power supply, double-sided tape, two small screws and a long screw with a nut.
Carefully cut off two approximately identical pieces of plastic with a knife and glue them with a small piece of double-sided tape to align them with the Dremel.

Don't forget to put on goggles and preferably a respirator, let's get to work.

I will digress a little, the glasses are clear for what, but I will explain the purpose of the respirator a little. The fact is that Dremel works with rotation up to 33 thousand revolutions per minute and the dust from working with it is quite fine. And in order not to inhale it is not clear what the dust consists of, you need a respirator

I guessed everything well workplace and having made two pieces of plastic the same, we proceed to cut a hole for the power connector with a knife and a pencil.
Enough scribbled in pencil upper part power connector, and attaching to right place on plastic - we get an approximate stencil for cutting.
Having cut out, we apply both plastics to the circuit, inserting the power connector in advance. Next, we look at how the main fastening screw passes through the entire structure, we outline the hole first on one side, and, having inserted it into the already drilled hole, we outline and make the second hole.
Next, take the second plate, where the nut will be. We thread and tighten the screw with the nut on it. Then, with a little effort, using a hot soldering iron, we press the nut into the plastic until it stops protruding. Cool and unscrew the screw.
We take both covers of our box and from the inside we make small belts about a millimeter by a millimeter, stiffening ribs will be inserted there, which are also decorative plugs covering the edges of the power circuit.
By and large, almost everything is ready, it remains only to make the mounts for the lamp itself.

To do this, we take the same white plastic and cut out two small rectangles, make holes with drills, first small, then larger, but the holes should not be exactly in the center. then the mounts will not allow the lamp to turn, they need to be made with a slight downward shift. Next, we twist with screws and stick double-sided tape on the outer base of the resulting mounting planes.

We insert the lamp connector into its power supply circuit, and the circuit into our self-made box and slowly twist it, but not completely.
Now let's start making the side walls. To do this, we outline the place of cutting in the already prepared "blank gasket" and cut out the wall in advance of a slightly larger size. We put it on the box and see how it fits. When you like the size, you can make a second wall.
Having attached the finished first wall as a template, we adjust the second in size.
When everything is ready and all the burrs are removed, we proceed to the assembly.
We take the power circuit, cut off the connector for external connection power supply and solder our connector for the power supply to it. We reassemble the entire box, having previously isolated all the bare contacts and cleaned all traces of fuss. We twist, and at the end, we insert stiffeners, after which we twist to such a state that the box does not fall apart. If not everything is holding well, you can glue the stiffening ribs along the edges with additional superglue so that it does not fall apart, neither from a fall, nor from hands.

Not everything turned out well for me, namely: the screw was outside the cover, so that it had to be cut down.

Then, on the side of the nut, we glue four small pieces of double-sided tape, so that later it can be quickly and easily removed. I also did not find a switch button, it will be soldered to the bp cord. later.

If someone does not want to mess around like that (I just had to understand the work of Dremel with different materials), he can find any suitable box and fix the circuit in it.

Who wants to have a backlight in the case, I can advise you to connect to any 12v line with the right resistance.

You can also try to use the lamp without its reflector (besides, it is not quite a reflector, but rather an absorber, because it is not specular, but white-black). But for this you need to be extremely attentive to the ends of the lamp, since the wires soldered into the glass are thick enough and can be broken off, or the glass may crack in these places. There are rubberized special holders on the edges of the lamp, I would recommend equipping some of my own fasteners on them. The lamp worked for about 40 minutes with my b.p. practically did not heat up, neither the reflector, nor the rubber bands on the sides of it. If the voltage supplied to the lamp is more than 9V, then the lamp will most likely overheat, and possibly fail. If you decide to use it without a reflector, although it will illuminate everything around, it will also shine into the eyes, which somehow did not seem enough to me.

I also want to warn you about the transformer in the lamp power circuit. I don’t know what current it gives out and what it is, but if you bring a finger, or another part of the body, close to its contacts, an electric arc occurs, which, for example, burned out a pattern on my finger. In this case, the distance to the contacts can be up to two millimeters.
The current, of course, will not kill, but you can get a small burn.

So here's the finished version..

From kind people, I got into my hands such a fairly aged scanner, Mustek 6000p, device Windows times 95 and large white plastic cases. As a rarity, it is not of great value, but it is a pity to throw it away without looking inside).

Actually, all its electronic contents, the body goes to the trash.

The illuminator from the scanning carriage is a conventional cold cathode fluorescent lamp (CCFL), similar to those used in LCD backlighting.

Carriage payment. On the left side we see a high-voltage inverter, it's time to try to light the lamp.

In the left corner is the integral stabilizer 7812, designated as Q8, it is easy to understand from which tracks the inverter receives power. At its input, when the scanner is turned on, there is about 14 volts, but the lamp does not light up, how to start it? There are not so many tracks leading to the board with the inverter from the connector that connects the carriage board to the main board, so let's assume that the key that starts the lamp is assembled on transistor Q5.

We close the resistor R3 connected to the base of the transistor with tweezers to + power, and ... let there be light!

Having figured out what's what, cut off all unnecessary, solder the jumper resistor between R3 and the power supply ...

... and pins for the printer's native power connector.

We get such a neat inverter board, we check again.

Of course, this is not enough to illuminate the workplace, but you can make a backlight in some drawer like a lamp in a refrigerator. As a body donor, an equally elderly mouse, the same age as the scanner, was a good fit. The switch will be a reed switch with normally closed contacts.

Assembled. It is a pity that the buttons do not carry any functional load =)

We fix the lamp and the body with double-sided tape. There is a magnet on the door hard drive on the same tape. Not very aesthetically pleasing, but it does the job.

More than enough to light up a small space

An attentive reader will notice that in the photo of the board in the mouse case there is already a jumper instead of a stabilizer - it is no longer needed, the inverter is powered by a home server, which is located on the same cabinet.