This article will focus on making original and unusual watches. Their uniqueness lies in the fact that the time is indicated using digital indicator lamps. Once upon a time, a huge number of such lamps were produced, both here and abroad. They were used in many devices, from watches to measuring equipment. But after the appearance LED indicators lamps gradually fell out of use. And so, thanks to the development of microprocessor technology, it became possible to create watches with a relatively simple circuit using digital indicator lamps.

I think it would not be amiss to say that mainly two types of lamps were used: fluorescent and gas-discharge. The advantages of luminescent indicators include low operating voltage and the presence of several discharges in one lamp (although such examples are also found among gas-discharge indicators, but they are much more difficult to find). But all the advantages of this type lamps have one huge disadvantage - the presence of a phosphor, which burns out over time, and the glow dims or stops. For this reason, used lamps cannot be used.

Gas discharge indicators are free from this drawback, because a gas discharge glows in them. Essentially, this type of lamp is a neon lamp with multiple cathodes. Thanks to this, the service life of gas-discharge indicators is much longer. In addition, both new and used lamps work equally well (and often used ones work better). However, there are some drawbacks - the operating voltage of gas-discharge indicators is more than 100 V. But solving the problem with voltage is much easier than with a burn-out phosphor. On the Internet, such watches are common under the name NIXIE CLOCK:

The indicators themselves look like this:

So, about design features Everything seems clear, now let's start designing the circuit of our watch. Let's start by designing a high-voltage voltage source. There are two ways here. The first is to use a transformer with a secondary winding of 110-120 V. But such a transformer will either be too bulky, or you will have to wind it yourself (the prospect is so-so). Yes, and voltage regulation is problematic. The second way is to assemble a step up converter. Well, there will be more advantages: firstly, it will take up little space, secondly, it has short-circuit protection and, thirdly, you can easily adjust the output voltage. In general, there is everything you need to be happy. I chose the second path, because... I had no desire to look for a transformer and winding wire, and I also wanted something miniature. It was decided to assemble the converter on MC34063, because I had experience working with her. The result is this diagram:

It was first assembled on a breadboard and showed excellent results. Everything started immediately and no configuration was required. When powered by 12V. the output turned out to be 175V. The assembled power supply of the watch looks like this:

A linear stabilizer LM7805 was immediately installed on the board to power the clock electronics and a transformer.
The next stage of development was the design of the lamp switching circuit. In principle, controlling lamps is no different from controlling seven-segment indicators, with the exception of high voltage. Those. It is enough to apply a positive voltage to the anode and connect the corresponding cathode to the negative supply. At this stage, two tasks need to be solved: matching the levels of the MK (5V) and lamps (170V), and switching the cathodes of the lamps (they are the numbers). After some time of thought and experimentation, the following circuit was created to control the anodes of the lamps:

And controlling the cathodes is very easy; for this they came up with a special K155ID1 microcircuit. True, they have long been discontinued, like lamps, but buying them is not a problem. Those. to control the cathodes, you just need to connect them to the corresponding pins of the microcircuit and submit data in binary format to the input. Yes, I almost forgot, it is powered by 5V. (well, a very convenient thing). It was decided to make the display dynamic, because otherwise, you would have to install K155ID1 on each lamp, and there will be 6 of them. The general scheme turned out like this:

Under each lamp I installed a bright red LED (it’s more beautiful this way). When assembled, the board looks like this:

We couldn’t find sockets for the lamps, so we had to improvise. As a result, the old connectors, similar to modern COM, were disassembled, the contacts were removed from them, and after some manipulations with wire cutters and a file, they were soldered into the board. I didn’t make panels for the IN-17, I did them only for the IN-8.
The hardest part is over, all that remains is to develop a circuit for the “brain” of the watch. For this I chose the Mega8 microcontroller. Well, then everything is quite easy, we just take it and connect everything to it in the way that is convenient for us. As a result, the clock circuit included 3 buttons for control, a DS1307 real-time clock chip, a DS18B20 digital thermometer, and a pair of transistors for controlling the backlight. For convenience, we connect the anode keys to one port, in this case it is port C. When assembled, it looks like this:

There is a small error on the board, but it has been corrected in the attached board files. The connector for flashing the MK is soldered with wires; after flashing the device, it should be unsoldered.

Well, now it would be nice to draw a general diagram. No sooner said than done, here it is:

And this is what it all looks like assembled:

Now all that remains is to write the firmware for the microcontroller, which is what was done. The functionality turned out to be as follows:

Display time, date and temperature. When you briefly press the MENU button, the display mode changes.

Mode 1 - time only.
Mode 2 - time 2 min. date 10 sec.
Mode 3 - time 2 min. temperature 10 sec.
Mode 4 - time 2 min. date 10 sec. temperature 10 sec.

When held, the time and date settings are activated, and you can navigate through the settings by pressing the MENU button.

The maximum number of DS18B20 sensors is 2. If the temperature is not needed, you can not install them at all; this will not affect the operation of the watch in any way. There is no provision for hot plugging of sensors.

Briefly pressing the UP button turns on the date for 2 seconds. When held, the backlight turns on/off.

By briefly pressing the DOWN button, the temperature is turned on for 2 seconds.

From 00:00 to 7:00 the brightness is reduced.

The whole thing works like this:

Firmware sources are included with the project. The code contains comments so it will not be difficult to change the functionality. The program is written in Eclipse, but the code compiles without any changes to AVR Studio. The MK operates from an internal oscillator at a frequency of 8 MHz. Fuses are set like this:

And in hexadecimal like this: HIGH: D9, LOW: D4

Also included are boards with bugs corrected:

This clock operates for a month. No problems were identified in the work. The LM7805 regulator and converter transistor are barely warm. The transformer heats up to 40 degrees, so if you plan to install the watch in a case without ventilation holes, you will have to use a higher power transformer. In my watch it provides a current of around 200mA. The accuracy of the movement is highly dependent on the quartz used at 32.768 KHz. It is not advisable to install quartz purchased in a store. The best results were shown by quartz from motherboards and mobile phones. Add tags

Hello, dear readers. For a long time I wanted to collect watches for gas discharge indicators, but I was sorely short of time, I finally finished this project. Below the cut is a little about what gas-discharge indicators are, as well as about how I assembled the watch, starting with the circuit and ending with the case.

Introduction

According to Wikipedia, the first gas-discharge indicators were developed in the 50s of the last century. Abroad, such indicators are called “Nixie”, the name comes from the abbreviation “NIX 1” - “Numerical Indicator eXperimental 1” (“experimental digital indicator, development 1”). This watch uses iconic Soviet-made indicators such as IN-12B.


By design, they are a glass flask inside of which there are ten thin metal electrodes (cathodes), each of which corresponds to one number from 0 to 9, the electrodes are folded so that different numbers appear at different depths. There is also one electrode in the form of a metal mesh (anode), located in front of all the others. The flask is filled with the inert gas neon with a small amount of mercury. When an electrical potential of 120 to 180 volts is applied between the anode and cathode direct current, a glow appears near the cathode and the corresponding number lights up. These indicators are valued for this soft orange light.

Additional Information

To be precise, IN-12B lamps have one more cathode - in the form of a point; it is not used in these watches.

Also in this watch, another gas-discharge indicator is used to separate hours and minutes - INS-1

The indication is carried out through the lens dome of the cylinder and looks like a luminous orange dot.

Scheme

The clock diagram was found on the Internet, author Timofey Nosov. It is based on the PIC16F628A microcontroller and the Soviet K155ID1 microcircuit, which is a high-voltage decoder for controlling gas-discharge indicators.


The lamps are powered using a step-up pulse converter assembled on field effect transistor, inductance, capacitor and diode, the PWM signal is generated by the microcontroller. This circuit uses dynamic indication; the microcontroller, using the K155ID1 decoder, controls the cathodes of all lamps at once, and synchronously controls the anodes of the lamps through optocouplers. The lamp switching speed occurs at a high frequency, and since gas-discharge indicators, like any lamp, need time to go out, the human eye does not see the flickering (I will say more - even the camera does not see it).
The circuit implements backup power using the CR2032 element; when the power is turned off, the indication goes out and the clock continues to run.

Electronic part

The clock circuit is divided into two parts - a board with lamps and the main board of the device.

Link to archive with file for Splint Layout -

Using LUT I made two boards


Assembling the board with lamps


I got the lamps from old Soviet equipment, and it was this find that prompted me to collect these watches.

Assembling the main board



The boards are connected via PLS and PBS connectors, which are soldered on the track side. This is what it looks like assembled:


I bought a PIC16F628A microcontroller -
I bought optocouplers -
Field effect transistor IFR840 -
The rest was in stock or found locally.

All that remains is to flash the microcontroller. We will flash it using the PICkit2 programmer, which we bought a long time ago -


We launch the PICkit2 program and flash our microcontroller


After flashing the firmware, I turn on the watch... but the numbers do not light up, only the second indicator (INS-1) blinks. After I found my mistake, a 47K resistor was installed in the lamp power circuit instead of a 4.7K resistor. After the replacement, the circuit started working, we need to make a housing.

Frame

I still have a piece of beech timber left, this is the same beech that was used to make the body of the “shaitan box” from my .


At first I wanted to cut out the body on a CNC machine, I agreed with my friend who works in furniture production. But, as it happens, sometimes there is no time, then other work urgently needs to be done. In short, after a month of waiting, I decided to do it myself.

I cut out a blank for the future body, marked it


I cut out a cavity for the insides, this was a labor-intensive step itself. First I drilled it out, then I removed the excess with a chisel, and then I sanded it.


Using a chisel, I made a recess for the glass and the back panel, glued the stops inside the case, and soaked everything in linseed oil.



I cut out a piece of the required size from darkened glass.


Did back panel, with holes for buttons and power connector


Put it all together, front view


Back view


In order for the clock to stand slightly at an angle, I glued two rubber feet to the bottom.


In the case of rare switching on of individual indicator cathodes and the activity of others, particles of metal sputtered by working cathodes settle on rarely used ones, which contributes to their “poisoning”. The device implements a method to combat this phenomenon; before changing the minutes, all numbers in all lamps are quickly searched. Demonstration of how this happens:


From the functionality - clock, alarm clock, brightness adjustment. Control is carried out by three buttons - “more”, “ok” and “less”.
By pressing the “ok” button you can cycle through the following modes:
– setting the current time clock (HH _ _);
– setting the minutes of the current time (_ _ MM);
– setting the alarm clock (HH._ _);
– setting the alarm minutes (_ _.MM);
– setting the current day of the week from 1 to 7 (0 _ _ 1);
– alarm goes off on Monday (1 _ _ 1);
– alarm goes off on Tuesday (2 _ _ 1);
– alarm goes off on Wednesday (3 _ _ 1);
– alarm goes off on Thursday (4 _ _ 1);
– alarm goes off on Friday (5 _ _ 1);
– alarm goes off on Saturday (6 _ _ 0);
– alarm goes off on Sunday (7 _ _ 0);
– lamp brightness from 0 to 20 (8 _ 05);
– hourly signal from 9:00 to 21:00 (9 _ _ 1).

This is what this beauty looks like in the dark




As a result, we have a beautiful thing made with our own hands. In the future, perhaps I will make another watch in a different case, I have one idea.

Thank you all for your attention. Add to favorites Liked +209 +319

In the last century, gas-discharge indicators were used very actively on many devices: in watches, measuring equipment, frequency meters, oscilloscopes, scales and many others. Over time, they were replaced by liquid crystal displays, the manufacturing technology of which is simpler and less expensive, and most importantly, they are more compact and have large quantity discharges. Liquid crystal displays make it possible to display readings with greater accuracy.

Scope of application today

Nowadays the industry no longer makes gas-discharge indicators with numbers, but at one time they were churned out so many that they are still collecting dust in warehouses and private stocks. They can already be called antiques, just like, for example, many homes have vintage candlesticks that are used as a decorative element of the interior. Likewise, clocks with gas-discharge lamps fascinate with their illumination and are an excellent addition to the interior of various rooms, especially those furnished in a retro style.

The thing is beautiful and useful, but, alas, it is no longer produced in factories. You can make them yourself or buy ready-made ones from people who specialize in their production. Many clock circuits have been developed using gas-discharge indicators on old and new microcircuits. Let's consider the simplest options.

Watch assembly steps

First, you need to understand the operating principle of IN-14 indicator elements; practically these are neon light bulbs with a group of cathodes in the form of numbers. Depending on the power supply, one or another cathode glows alternately; the principle of an incandescent lamp with a gas-discharge process is used.

The service life of such indicators is enormous, because there is no long-term and heavy load on one cathode. For full illumination, a voltage of at least 100 V is required, so let’s start the design with a power source.

power unit

The option with a transformer, the secondary winding of which will have 170 or 180 V, is immediately excluded due to its large dimensions and weight. Selecting iron, wires and winding yourself is a thankless and tedious task. It is more practical to use a voltage converter on the MC34063 chip, which has small dimensions, weight and stable parameters.

All elements are mounted on a printed circuit board; after assembly, in most cases, no adjustment is required; with 10–12 V, the converter produces 175–180 V. As you can see, there is a transformer in the circuit, but it is very small and easily accessible for quick self-production; one can be purchased at retail networks. The output of the secondary winding is 9–12 V alternating current come to the diode bridge (rectifier). The linear stabilizer LM7805 is designed to power the electronic elements of watches.

Circuit for turning on lamps

This circuit solves the problem of matching the control voltage on the 5 V microcircuit and the controlled supply voltage of the anodes. A positive potential of 180 V is applied to the anode, and a negative potential is applied to the cathodes of the corresponding numbers.

The cathodes are switched on using a circuit based on the old K155ID1 microcircuit, which is powered by a voltage of 5 V, which in our case is very successful. 155-series microcircuits have been discontinued, but are not in short supply; they can easily be purchased in retail chains and radio markets. In order not to solder a microcircuit to each lamp, the cathode control circuit is made according to a dynamic principle.

Now the power supply, cathode and anode control circuit must be connected to the DS1307 clock processor; the Mega8 microcontroller is ideal for coordination.

Watch with controller and control buttons

This scheme includes:

• watch DS1307;
• Mega8 controller;
• DS18B20 digital thermometer;
• transistors for LED backlighting;
• buttons to control time settings.

If necessary, this scheme can be significantly simplified, removed LED backlight, digital thermometer and second discharge lamps with cathode and anode control elements.

Microcontroller firmware

The software for the clock from gas-discharge indicator lamps is written in Eclipse, transmitted without distortion to AVR Studio, codes with comments, which greatly simplifies the process.

As a result of the firmware, certain modes and the process of managing them are installed. When you briefly press the “MENU” button, the following modes are displayed in a circle:

• mode No. 1 – time (displayed constantly);
• mode No. 2 – 2 min. time, 10 sec. date of;
• mode No. 3 – 2 min. time, 10 sec. temperature;
• mode No. 4 – 2 min. time, 10 sec. date and 10 sec. temperature;
• The time and date setting mode is set by holding the “MENU” button;
• a short press on the “UP” button (2 seconds) displays the date, holding this button turns the backlight off or on;
• short press “DOWN” (2 sec.) displays the temperature;
• brightness reduction by hourly program from 00.00 to 7 am.

Connection of main elements and operating features

Ultimately, the entire system consists of three printed circuit boards:

• Power supply, voltage converter on base MC34063

• Board with controller Mega8 and DS1307 watch

For compactness, the board is made with a double-sided arrangement of elements; this version of printed circuit boards is not a dogma; there are others. When the clock, control of the cathodes and anodes are mounted on one board, and the power supply on another, smaller lamps - IN-8 - are used to discharge seconds. Sometimes the lamps are taken out altogether separate panel and make a two-level design, on the first level there is a board with a clock microcircuit and elements for controlling the cathodes and anodes. At the second level there is a board with panels for lamps; everything depends on the developer’s imagination.

IN-14 lamps are no longer in production; there may be a problem with purchasing panels for them. In this case, you can use contacts D-SUB connectors"female" format or collet rulers suitable in diameter.

The plastic of the ruler can be carefully crushed with pliers and the contacts can be removed, which are soldered into the drilled holes on the printed circuit board.

Now all that remains is to pack this structure into a case (the simplest option is a rectangular box). The material can be very varied: plastic, plywood, covered with leather or other decorative material.

The power supply transformer heats up by no more than 40 °C, so it is recommended to make ventilation holes in the case to ensure a stable current of 200 mA. The accuracy of the clock depends on the stable operation of 32.768 KHz quartz, which is recommended to be taken from PC motherboards or cell phones, since low-quality products are often found in retail chains.

This method of making watches using gas-discharge lamps can be carried out by a person who has certain knowledge in electronics and practical skills. Beginners can use the services of the site http://vrtp.ru/index.php?showtopic=25695. You can order ready-made ones for 800 rubles printed circuit boards With detailed instructions, which spell out what to solder and where. For 2,500, a complete “Do it yourself” kit is sold, on lamps with a stitched microcircuit and other parts. You can buy a ready-made watch for 3,500 rubles, but this is not interesting if you want to assemble something with your own hands.

It raised a lot of questions from those who wanted to assemble it, or from those who had already assembled it, and the clock circuit itself has undergone some changes, I decided to write another article devoted to clocks with gas-discharge indicators. Here I will describe improvements/fixes to both the circuit and firmware.

So, the very first inconvenience when using this watch in an apartment was the brightness. If during the day it did not interfere at all, then at night it illuminated the room quite well, interfering with sleep. This became especially noticeable after redesigning the board and installing blue LEDs in the backlight (red backlighting turned out to be an unsuccessful option, since the red light drowned out the glow of the lamps). Reducing the brightness over time did not have much effect, because I go to bed at different times, and the clock dims the brightness at the same time. Or I’m still awake, but the brightness has decreased and the time is not visible. Therefore, I decided to add a light sensor, or, more simply, a photoresistor. Fortunately, there were plenty of ADC pins for connection. I did not make a direct dependence of brightness on the level of illumination, but simply set five gradations of brightness. The range of ADC values ​​was divided into five intervals and each interval was assigned its own brightness value. The measurement is taken every second. The new circuit node looks like this:

A conventional photoresistor acts as a light sensor.

The next change affected the clock's power supply. The fact is that the use of a linear stabilizer imposed restrictions on the supply voltage range, plus the stabilizer itself got hot during operation, especially when the LEDs were at full brightness. The heating was weak, but I wanted to get rid of it completely. Therefore, another switching stabilizer was added to the circuit, this time a step-down one. The microcircuit remains the same as in the Step-Up converter, only the circuit has changed.

Everything here is standard, from the datasheet. The current required by the circuit for operation is less than 500mA and an external transistor is not needed, the internal key of the microcircuit is enough. As a result, any heating of the supply part of the circuit stopped. In addition, this converter is not afraid of short circuits at the output and overloads. It also takes up less space on the board and will protect against accidental reversal of the supply voltage. In general, solid advantages. True, the power supply pulsations should have increased, but this does not have any effect on the operation of the circuit.

In addition to the electronic part, the appearance devices. There is no longer a huge pile of wires. Everything is assembled on two boards, which are folded into a “sandwich” and connected via PLS/PBS connectors. The boards themselves are held together with screws. The top board contains lamps, anode transistor switches and backlight LEDs. The LEDs themselves are installed behind the lamps, not under them. And on the bottom there are power circuits, as well as an MK with wiring (in the photo there are more old version watches that did not yet have a light sensor). The size of the boards is 128x38mm.

IN-17 lamps were replaced with IN-16. They have the same character size, but the form factor is different: After all the lamps became “vertical”, the board layout was simplified and the appearance improved.

As you can see in the photo, all the lamps are installed in unique panels. The sockets for IN-8 are made from female D-SUB connector contacts. After removing the metal frame, he easily and naturally parts with these same contacts. The connector itself looks like this:

And for IN-16 from the contacts of a conventional collet ruler:

I think that we must immediately put an end to possible questions about the need for such a decision. Firstly, there is always a risk of breaking the lamp (a cat might climb in or the wire might be pulled, in general, anything can happen). And secondly, the thickness of the connector lead is much smaller than the thickness of the lamp lead, which greatly simplifies the board layout. Plus, when sealing the llama into the board, there is a danger of breaking the seal of the lamp due to overheating of the output.

Well, as usual, a diagram of the entire device:

And video of the work:

They work stably, no bugs have been identified in six months of operation. In the summer we were left without food for more than a month while I was away. I arrived, turned it on - time did not run away and the operating mode did not go astray.

The clock is controlled as follows. When you briefly press the BUTTON1 button, the operating mode is switched (CLOCK, CLOCK+DATE, CLOCK+TEMPERATURE, CLOCK+DATE+TEMPERATURE). When you hold down the same button, the time and date setting mode is activated. Changing the readings is done using the BUTTON2 and BUTTON3 buttons, and moving through the settings is done by briefly pressing BUTTON1. Turning the backlight on/off is done by holding the BUTTON3 button.

Now you can move on to the next version of the circuit. It is made using only four IN-14 lamps. There is simply nowhere to get small lamps for seconds, just like IN-8. But buying IN-14 at an affordable price is no problem.

There are almost no differences in the circuit, the same two pulse converters for power supply, the same AtMega8 microcontroller, the same anode switches. The same RGB backlight... Although wait, there was no RGB backlight. So there are still differences! Now the watch can glow in different colors. Moreover, the program provides the ability to sort through colors in a circle, as well as the ability to fix the color you like. Naturally, while maintaining the color and operating mode in non-volatile memory MK. I thought for a long time about how to use the dots in a more interesting way (there are two of them in each lamp) and in the end I displayed seconds on them in binary format. On clock lamps there are tens of seconds, and on minute lamps – units. Accordingly, if we have, for example, 32 seconds, then the number 3 will be made from the points of the left lamps, and 2 from the right lamps.

The form factor remains “sandwich”. On the bottom board there are two converters to power the circuit, MK, K155ID1, DS1307 with a battery, a photoresistor, a temperature sensor (now there is only one) and transistor switches for lamp points and RGB backlights.

And on the top there are anode keys (by the way, they are now in SMD version), lamps and LED backlights.

Everything looks pretty good when assembled.

Well, a video of the work:

The clock is controlled as follows. When you press the BUTTON button briefly1 switches the operating mode (CLOCK, CLOCK+DATE,CLOCK+TEMPERATURE,CLOCK+DATE+TEMPERATURE). When you hold down the same button, the time and date setting mode is activated. Changing the readings is done using the BUTTON2 and BUTTON3 buttons, and moving through the settings is done by briefly pressing BUTTON1. Changing the backlight illumination modes is carried out by briefly pressing the BUTTON3 button.

The fuses remained the same as in the first article. The MK operates from an internal 8 MHz oscillator.In hexadecimal:HIGH: D9, LOW: D4 and a picture:

MK firmware, sources and printed circuit boards in format are included.

List of radioelements

Designation	Type	Denomination	Quantity	Note	Shop	My notepad
	With RGB backlight
U1	Chip	K155ID1	1			To notepad
U2	MK AVR 8-bit	ATmega8A-AU	1			To notepad
U3	Real Time Clock (RTC)	DS1307	1			To notepad
U4, U5	DC/DC pulse converter	MC34063A	2			To notepad
P9	temperature sensor	DS18B20	1			To notepad
Q1, Q2, Q7-Q10	Bipolar transistor	MPSA42	6	MMBTA42		To notepad
Q2, Q4-Q6	Bipolar transistor	MPSA92	4	MMBTA92		To notepad
Q11-Q13, Q16	Bipolar transistor	BC857	4			To notepad
Q14	Bipolar transistor	BC847	1			To notepad
Q15	MOSFET transistor	IRF840	1			To notepad
D1	Rectifier diode	HER106	1			To notepad
D2	Schottky diode	1N5819	1			To notepad
L1, L2	Inductor	220μH	2			To notepad
Z1	Quartz	32.768 kHz	1			To notepad
BT1	Battery	Battery 3V	1			To notepad
HL1-HL4	Light-emitting diode	RGB	4			To notepad
R1-R4	Resistor	12 kOhm	4			To notepad
R5, R7, R9, R11, R34, R35	Resistor	10 kOhm	6			To notepad
R8, R10, R12, R14	Resistor	1 MOhm	4			To notepad
R13-R18, R37, R38, R40	Resistor	1 kOhm	9			To notepad
R19, ​​R20, R33, R39, R41-R43, R46, R47, R51, R53	Resistor	4.7 kOhm	11			To notepad
R21, R24, R27, R30	Resistor	68 ohm	4			To notepad
R22, R23, R25, R26, R28, R29, R31, R32	Resistor	100 Ohm	8			To notepad
R36	Resistor	20 kOhm	1			To notepad
R44	Resistor

Answer

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A simple clock - a thermometer with gas-discharge indicators.

Watch features

Time:

Date of:(Date - Month - Day of the week)

Temperature:

6 display modes and auto-display of date and temperature every 35 seconds.

Press the "-" button to select display modes.
http://www.youtube.com/watch?v=QReDKfZJKd0

The watch is assembled using a minimum of microcircuits:

PIC16F628A- clock controller.
DS1307- the watch itself.
BU2090- cathode decoder.
MAX1771- voltage transformer.
DS18B20- temperature sensor - If you don't need a thermometer, you don't need to install it.
DS32KHz- generator microcircuit for precision.
If accuracy is not needed and you just select the exact quartz at 32.768
then DS32KHz can not be installed.

Description of buttons:
The "-" button is in the clock setting mode and the button is used to cycle through display modes in the clock operating mode.
Button "OK" - to enter the clock setting mode.
The "+" button in the clock setting mode and the date and temperature display button in the clock operating mode.

Display modes:

1 - the numbers fade out smoothly and new ones appear smoothly.

2 - the clock works as usual; in this mode the “pendulum” works.

3 - the numbers change when changing by brute force; in this mode the “pendulum” works.

4 - the numbers overlap each other when changing.

5 - display mode changes every day at 00:00.

6 - indication mode changes every hour.

Enable/disable automatic display of date and temperature every 35 seconds.
Press and hold the “+” button for 3 seconds to display the date/temperature.

Time setting:
To set the time, press and hold the “OK” button for 3 seconds while the time is displayed.
The watch enters time setting mode and the hours begin to flash.
Use the “-” and “+” buttons to set the hour and press the “OK” button and proceed to setting the minutes.
And so on in the sequence hour > minutes > date > month > day of the week.
When you hold the "-" or "+" buttons for a long time, the numbers automatically decrease or increase on their own.

Setting the cathodes, that is, the order of numbers.
Any lamp can be used in the clock.
For the board included in the project, you can use any lamps with flexible leads
Type IN-8-2 or IN-14 or IN-16 or IN-17.
The project also contains a board and firmware for IN-12 - The firmware is different because the lamps are not in place, and a board for IN-18.

The controller firmware is designed to use IN-14 in the native board,
if you use other lamps or draw your own board
After assembling the board and starting the clock, you need to reassign the numbers.
Because their order is violated - for example, instead of 0 there will be 7 or instead of 5 - 3.

Purpose of numbers:
Necessary if you will use your board with other lamps.
Or other lamps for this board - for example IN-8-2 or IN-16.
Cathodes can be connected to the BU2090 as convenient.
The only exception is for points if they are in the lamps (14 - right, 15 - left points, BU2090 pins).
If there are no points, then you don’t have to connect them.

Press and hold the OK button and turn on the clock.
A number in the 1st or 3rd digit lights up.

We release the button and the numbers begin to be sorted.
We need to assign numbers from 0 to 9.
When they appear, press the “+” button and so on sequentially from 0 to 9.

After which the 4th digit lights up and 0 and 1 begin to blink.
This is to enable/disable the running dot.
If you press the "+" button to 0, the function is disabled.

Then the 5th digit lights up - this is the permission for the blinking of the second lamps.
In case you place the second lamps in the center instead of the second dots.

After which the clock goes into working mode.

The boards were drawn using Sprint Layout 3.0.

Photo of the top part of the board with labeled elements for greater clarity.