When we come to visit her, we are always greeted by a rich table, with a large number of dishes. Therefore, we immediately decided to make a device useful in the kitchen. Together we often play various board games - lotto, various dice games. So, our device should help here as well.
After thinking a little, the son decided to do advanced kitchen timer. I helped him a little with the scheme. The main functions of our gift:
- Timer mode up to 3 hours
- Stopwatch mode
- loud signal
- Compact size
- "Eternal" batteries - rechargeable batteries, charging like a phone, via micro usb
- And of course games - dice (random number from 1 to 6), lotto, bomb (very fun game)
We select components
As an indicator, we chose a three-digit LED indicator with a common anode - it has only 11 pins, which is very convenient. It is not difficult to buy, and in principle, it is quite economical in terms of power consumption (but of course not LCD).Microcontroller - STM8S003F3P6 - we have already worked with it, so everything is familiar. ST-link is already there.
The charge microcircuit and the entire harness for the MK, like for a bicycle computer.
As a tweeter, very compact and loud HC0903A tweeter
Battery - LIR2032. Only 45 mAh, but this is enough for 40 hours of continuous timer operation. We decided to abandon the quartz resonator (we need conclusions), we don’t need special accuracy, and the STM8 has a fairly accurate internal oscillator. Charge chip - TP4056.
Management - 2 clock buttons. The device is in sleep mode all the time, the consumption is less than 5 μA, it can sleep for a long time. They didn’t make a protection board for the battery, it’s especially not needed. MK has a lower limit of 3V, so it won’t sag much. When turned on, music plays, the indicator turns on (current surge), and if the battery is dead, the MK will reboot and go into sleep mode, which is a signal to charge. It is charged with a current of 100 mA for about 40 minutes, which, in principle, is very fast. The scheme and the program can be downloaded on github, link at the end.
The son decided to make the case himself from a mounting box 40 x 16 mm. I painted it with acrylics, cut out a piece from a DVD disc as glass. It turned out very nice.
The son did the board tracing himself in Kicad. The location of the component was invented by him. The buttons are on the sides of the indicator, the buzzer is at the bottom, the battery is on it. Everything is tight, nothing is loose anywhere. The payment is two-sided. Made from single-sided fiberglass with a thickness of 0.8 mm using the method of cold toner transfer. The two halves of the board were connected and fixed with jumpers. Of the connectors - micro usb, power and programming.
Program
This indicator has a common anode, so only one discharge can be output at a time. To output three digits at the same time, dynamic indication is required.It is very easy to do this programmatically. The timer is activated, and at regular intervals, with a high frequency, for example, every 300 μs, we will output one bit in a circle - 1-2-3-1-2-3. We will be shown that the numbers are lit at the same time, like in a movie. If you additionally add more empty digits, then you can control the brightness. That is, there will be such an information output scheme - 1-2-3-empty-empty-empty-empty-1-2-3-empty-empty ... Brightness control is needed in order to reduce power consumption. Thus, for example, without the use of brightness, one discharge consumes 24 mA, and with the application it can be reduced to 1-2 mA. At the same time, the numbers are still clearly and far visible. The son played with the frequency, brightness, when everything stopped flickering, he liked it. It turned out that programming this type of indicator is quite easy and convenient.
The second difficult moment is to come up with a simple, as they say, intuitive interface, when we have 3 digits of the indicator and 2 buttons. But I think he succeeded.
They came up with buttons like this:
- Right button - long press, change modes, there are three of them - Timer, Stopwatch, Games
- Right button - single press, submode change. For the timer - this is the choice of preset times, for the stopwatch - the choice of a regular stopwatch and with confirmation, for the game - resp. Various games
- Left button - single press - start / stop or move in the game, long press - setting mode, programming
- When a timer is selected, a certain number of preset settings is immediately displayed (For example, 5,15,30 minutes), they can be reprogrammed, stored in ROM
- When stopwatch is selected - then 000
- When games - L - lotto, 6 - bomb, C - cube.
- The numbers are displayed cunningly on the indicator, since there are only three digits, then we display the maximum number of significant elements. For example, the timer is 200 minutes 30 seconds - then we output 200. If the timer is 10 minutes 15s, then we output 10.1, if 1 minute 25s, then 1.25. At the same time, in order to understand that the timer or stopwatch is running, the dot flashes to the beat of the seconds.
- When the stopwatch is stopped, for example, for 10 minutes 25 seconds, then we show alternately 10. and.25, once a second, in order to see the seconds too.
Tests
The first tests took place at school. Instead of a cube, fortune telling on grades. The whole class guessed. Then the bomb is a super game. The device guesses a random time from 5 to 20 seconds and starts ticking every second. You pass it around. When the timer reaches zero - an explosion signal. The one who has the device in his hands lost.The first tests of the stopwatch and timer went off with a bang. They recorded different times, checked with the exact clock, the error was 1-2 seconds per hour. Received the sound of the signal.
Presentation of a gift
The birthday has come. Grandma quickly completed the training and was very happy. All together experienced Lotto, fully automated. Every 5 seconds, the device beeps and gives out a new number from the remaining ones in the bag. Everyone plays, drives the device! Who did not have time, he was late.Results
So, the device turned out just fine. Programming practice is very interesting. If you are also interested in microcontrollers, then you can make yourself (or as a gift) the same one and program it. You will definitely learn:- make boards
- solder smd components
- programming STM8
- work with batteries
- handle buttons
- make different sounds
- work with timers and handle temporary events
- fight energy consumption
How to choose a clock for the kitchen and what types are there?
To any style of kitchen interior, you can choose a clock that will harmoniously complement it. Watches are the most important accessory, without which it is difficult to imagine a modern home. In whatever style the interior is decorated, you can always pick up a clock that fits perfectly into it and emphasizes its features. In the kitchen, a clock must be mandatory - after all, when cooking, it is always important to keep track of time. And here mobile phones and other modern devices will not help at all. After all, sometimes you look at how much time you need quickly, and your hands can be busy cooking or just be dirty. How to choose a clock for the kitchen?
Purpose and types of kitchen clocks
Clocks in the kitchen have many roles:
- show the exact time;
- act as a timer for cooking;
- decorate the interior.
There are a lot of types of clocks for the kitchen - these are classic models, and original, and funny playful little things. But with an abundance of various models in the kitchen, a fairly limited number of types of watches are used. A grandiose grandfather clock would hardly be appropriate here, for which there is hardly a place in the kitchen. But all kinds of wall clocks, timers, desktop options are well suited.
Wall clock minimal "Time" will fit perfectly into the loft style, minimalism or Hi-Tech
Kitchen clock can be a characteristic piece of furniture
Kitchen clocks can have a variety of purposes.
Where to place the clock
Where is the clock in the kitchen? Convenience is paramount here. The kitchen clock should be in the place where you can immediately get a look when working. Or, in order to see what time it is, you need to turn around slightly. As a rule, the clock is hung on a wall located in the area of \u200b\u200bthe working area or the dining area. It can be original or classic wall clock in a different style.
The question of the location of the clock for each kitchen is individual
Important: On the one hand, when cooking, the clock is very important and they are drawn to be placed near the stove. On the other hand, fat and soot will then settle on them, which does not add beauty to the watch. In this case, you can either close the clock for the kitchen with glass, or place a timer in this place.
If the kitchen is small, then just one hour is enough. They can be placed on the wall that combines the working and dining areas. Then the clock will be visible from everywhere and to everyone. If the kitchen is large, then it is appropriate to have several hours on it. In this case, you can choose wall and table clocks. A table clock can be placed on the work area, on the island or on the bar counter.
Wall clock in the kitchen
Wall clocks are the most popular type of clock in the kitchen. Their practical function is to show the time. But in fact, their decorative role in the kitchen is no less important. They sometimes become one of the most noticeable and striking elements of the interior. Wall clocks can both give completeness and harmony to the interior, and completely destroy it if they are made in a different style than the rest of the room.
The practical function of kitchen wall clocks is as important as their decorative role.
When choosing a wall clock for the kitchen, it is important to consider the overall style of the room.
When choosing a watch, it is important to decide on their style. If the room is made in a classic style, then the clock should be strict, classic. If Art Nouveau reigns around, then rich decor, an abundance of ornament and original forms are welcome. In high-tech kitchens, watches with a minimum of decorative elements, strict, concise forms will look very impressive. Very original clock - with a transparent dial, creating the illusion of arrows on the wall. Or, on the contrary, an asymmetric watch with barely visible hands and no numbers.
The informal task of the kitchen wall clock is to cheer you up before the working day.
Cheerful, cool clock models are often chosen for kitchens. And this is not surprising - not everyone is able to feel cheerful and fresh in the morning, getting ready for work. And wall clocks are designed to cheer you up before leaving for work. Funny watches can be of different shapes and colors - in the form of all kinds of funny characters, cartoon characters. Arrows can be forks and spoons. By the way, this technique - the use of a fork and a spoon in the kitchen is often used. And it can be not only arrows. You can replace the handles on the headset and choose cool models in the form of a spoon and fork. And then hang a clock where forks and spoons represent arrows. Get the finished style of the room.
Original wall clock for the kitchen (video)
Do it yourself
By the way, you can make such a watch yourself. For this, the most common plastic disposable forks and spoons, a plastic lid from a jar, glue and acrylic paints are suitable.
From disposable plastic utensils and an old clockwork, you can make an original clock
In this case, the forks with spoons are the dial, not the hands. Forks, spoons, knives are fixed on a plastic cover in a circle. Then all this is covered with paint.
Important: it is best to use paint in an aerosol can. Then it lays down evenly and it turns out very beautiful and not artisanal. You can purchase creative spray paints for decorative work. With their help, you can create real designer things.
After the paint dries, the clock mechanism is attached with hands that can be taken from an old clock.
Original creative watches also cheer you up. Wall clock in the form of scrambled eggs, with cooks and cats with shifty eyes do not leave anyone indifferent. If you want creativity, but do not want kitsch, then you can choose a watch in which the dial is made up of coffee beans and other cereals.
Do-it-yourself fork-spoon kitchen clock (video)
Provence style clock
Watches in Provence style deserve special attention. By and large, the Provence style is a variation of the folk style. Provence is characterized by natural materials, pastel colors, an abundance of light, some ostentatious simplicity. The main thing is that Provence is based on decorative elements. An abundance of ceramic dishes in blue and white, open shelves, curtains and tablecloths with a floral pattern, furniture painted in small flowers and stripes.
Provence-style watches must be round, emphatically simple in shape. They can be painted in small patterns or have artificial aging. Provence-style clocks should not be bright and conspicuous - they should be organically woven into the interior.
Wall clock in Provence style will harmoniously fit into the interior of any kitchen
How to choose the right watch
Of course, first of all, the clock is chosen in the same style as the decor of the entire kitchen. Otherwise, the room will look tasteless. But when choosing a watch, they take into account not only the style in which they are made.
To make the kitchen look organic, pay attention to the following points:
- The clock should match the color scheme of the interior. They are either made in companion colors or, on the contrary, in a contrasting color to the main color of the walls.
The color of the clock should be combined with the color palette of the entire interior.
The material from which the watch is made must be practical
For a small kitchen, a small dial is acceptable, or its complete absence.
Kitchen clock should be chosen in a style that matches the style of your kitchen
- The size of the clock is selected based on the size of the kitchen. In a small kitchen, the dimensions of the dial should also be small - a “station” clock with a diameter of up to 50-100 cm will look extremely ridiculous in a 7-meter kitchen. In the same way, in large kitchens, small wall clocks can be completely lost on the wall.
- The material from which the kitchen clock is made must be hygienic and withstand wet cleaning. Since the kitchen is a place where food is constantly being cooked, it is more than likely that greasy burning will get on household items. Therefore, the clock will have to be wiped more often than in the living room. And use detergent. For the kitchen, more suitable materials are plastic, metal, glass.
Clock timer for the kitchen
A clock timer is just a necessary thing for the kitchen. And even if at first it seems that you can safely do without them, but as soon as a timer appears in the kitchen, they begin to use it very actively.
Currently on sale:
- mechanical timer;
- electronic kitchen timer.
An electronic timer is very similar to an electronic desk clock. It can work on batteries or mains.
Advantages of an electronic timer:
- compactness - due to its small size, such a timer can be carried from room to room, even carried in your pocket. In this case, you can always know exactly how much is left to cook the dish;
- high accuracy of work - the timer counts down the time up to a second;
- aesthetic appearance.
Electronic clock-timer for the kitchen is very compact and accurate in operation.
The disadvantages of electronic timers include the fact that you need to change the batteries. And sometimes it stops working due to the fact that they forgot to do it on time.
A mechanical timer is often built into the stove. There is a model of a mechanical timer that can be carried and placed on the table.
The advantages of a mechanical timer are undeniable:
- it is extremely easy to work;
- does not break;
- long service life;
- no need to spend money on batteries.
Despite its simplicity, a mechanical timer can decorate the kitchen - manufacturers are trying to give the timers an aesthetic appearance.
The principle of operation of the timer is simple - there is a spring inside the device, which is wound up by the handle and begins to gradually unwind, counting the time. After the set time has elapsed, the timer emits a signal.
There are built-in timers. They are built into household appliances - a multicooker, a microwave oven, a stove. The built-in timer has only one drawback - it cannot be transferred.
A mechanical kitchen timer is more durable than an electronic one.
The mechanical type timer is very light and easy to use.
Manufacturers are trying to draw attention to their products and create very original timers that can carry different functions. For example, there are timers-thermometers. Such timers have a sensor on the spoke. The needle is immersed in the dish and a certain temperature is set at which the dish is considered ready. When this temperature is reached, the timer gives a signal. With this timer, you can not be afraid to overcook meat or fish.
The egg timer can be immersed in water along with real chicken eggs. It will beep as soon as the eggs are cooked. There is even a timer that simultaneously reports the readiness of spaghetti and the estimated number of servings.
By the nature of fastening, timers are:
- wall;
- desktop;
- mounted on a vertical wall with a suction cup.
It is especially important what material the timer is made of. Since the kitchen is a place where there are aggressive environments, the timer must be resistant to moisture and wet cleaning. In addition, the timer is often taken with dirty hands. Its surfaces must therefore be of a material which is not affected by this. The best material is stainless steel and plastic.
But since timers also become an element of the interior, it is important that they match the overall style. For high-tech kitchens, electronic models with a large LCD display are suitable, and for classic and Provence-style interiors, mechanical models in the form of vegetables and fruits are suitable.
Original do-it-yourself clock for the kitchen (video)
Conclusion
Whatever watch is chosen, it will always help you keep track of time. And of course decorate your kitchen!
Timer circuit on the counter K561IE16 |
The design is made on only one chip K561IE16. Since, for its proper operation, an external clock generator is needed, in our case we will replace it with a simple blinking LED.
As soon as we apply voltage to the timer circuit, the capacitance C1 will start charging through the resistor R2 therefore, a logical unit will briefly appear on pin 11, resetting the counter. The transistor connected to the meter output will open and turn on the relay, which will connect the load through its contacts.
With flashing LED with frequency 1.4 Hz pulses are sent to the clock input of the counter. With each pulse transition, a counter is counted. Through 256 impulses or about three minutes, a logical unit level will appear at pin 12 of the counter, and the transistor will close, turning off the relay and the load switched through its contacts. In addition, this logical unit passes to the DD clock input, stopping the timer. The operating time of the timer can be selected by connecting point "A" of the circuit to various outputs of the counter.
The timer circuit is made on a microcircuit KR512PS10, which has in its internal composition a binary counter-divider and a multivibrator. Like a conventional counter, this microcircuit has a division ratio from 2048 to 235929600. The choice of the required ratio is set by applying logic signals to the control inputs M1, M2, M3, M4, M5.
For our timer circuit, the division factor is 1310720. The timer has six fixed time intervals: half an hour, an hour and a half, three hours, six hours, twelve hours and a day of an hour. The frequency of operation of the built-in multivibrator is determined by the resistor values R2 and capacitor C2. When switching switch SA2, the frequency of the multivibrator changes, and passing through the counter-divider and the time interval.
The timer circuit starts immediately after power is turned on, or you can press the SA1 toggle switch to reset the timer. In the initial state, the ninth output will be a logical unit level, and the tenth inverse output, respectively, will be zero. As a result, the transistor VT1 connect the LED part of the optothyristors DA1, DA2. The thyristor part has an anti-parallel connection, this allows you to adjust the alternating voltage.
At the end of the countdown, the ninth output will go to zero and turn off the load. And at output 10, a unit will appear, which will stop the counter.
The timer circuit is started by pressing one of the three buttons with fixing the time interval, while it starts the countdown. Parallel to pressing the button, the LED corresponding to the button lights up.
At the end of the time interval, the timer emits an audible signal. A subsequent press will disable the circuit. Time intervals are changed by the denominations of the radio components R2, R3, R4 and C1.
Timer circuit, which provides a turn-off delay, is shown in the first figure. Here, a p-channel transistor (2) is included in the load power circuit, and an n-channel transistor (1) controls it.
The timer circuit works as follows. In the initial state, the capacitor C1 is discharged, both transistors are closed and the load is de-energized. With a short press on the Start button, the gate of the second transistor is connected to a common wire, the voltage between its source and gate becomes equal to the supply voltage, it instantly opens, connecting the load. The voltage surge that occurred on it through the capacitor C1 enters the gate of the first transistor, which also opens, so the gate of the second transistor will remain connected to the common wire even after the button is released.
As the capacitor C1 is charged through the resistor R1, the voltage across it rises, and at the gate of the first transistor (relative to the common wire) it decreases. After some time, depending mainly on the capacitance of the capacitor C1 and the resistance of the resistor R1, it decreases so much that the transistor starts to close and the voltage at its drain rises. This leads to a decrease in the gate voltage of the second transistor, so the latter also begins to close and the voltage at the load decreases. As a result, the gate voltage of the first transistor begins to decrease even faster.
The process proceeds like an avalanche, and soon both transistors close, de-energizing the load, the capacitor C1 quickly discharges through the diode VD1 and the load. The device is ready to start again. Since the field-effect transistors of the assembly begin to open at a gate-source voltage of 2.5 ... 3 V, and the maximum allowable voltage between the gate and source is 20 V, the device can operate at a supply voltage of 5 to 20 V (nominal voltage of capacitor C1 should be a few volts more than the supply). The turn-off delay time depends not only on the parameters of the elements C1, R1, but also on the supply voltage. For example, increasing the supply voltage from 5 to 10 V leads to its increase by about 1.5 times (with the values of the elements indicated in the diagram, it was 50 and 75 s, respectively).
If, with closed transistors, the voltage across resistor R2 turns out to be more than 0.5 V, then its resistance must be reduced. A device that provides a turn-on delay can be assembled according to the circuit shown in Fig. 2. Here, the assembly transistors are connected in much the same way, but the voltage to the gate of the first transistor and capacitor C1 is supplied through resistor R2. In the initial state (after connecting the power source or after pressing the SB1 button), the capacitor C1 is discharged and both transistors are closed, so the load is de-energized. As it charges through resistors R1 and R2, the voltage on the capacitor rises, and when it reaches a value of about 2.5 V, the first transistor begins to open, the voltage drop across resistor R3 increases and the second transistor also begins to open. When the voltage at the load rises so much that the diode VD1 opens, the voltage across the resistor R1 rises. This leads to the fact that the first transistor, and after it the second one, opens faster and the device abruptly switches to the open state, closing the load power circuit
The timer circuit is a restart, for this you need to press the button and hold it in this state for 2 ... 3 s (this time is enough to completely discharge the capacitor C1). The timers are mounted on printed circuit boards made of fiberglass foiled on one side, the drawings of which are shown respectively in Fig. 3 and 4. The boards are designed for the use of a diode of the KD521, KD522 series and parts for surface mounting (resistors R1-12, size 1206 and a tantalum oxide capacitor). Setting up devices is reduced mainly to the selection of resistors to obtain the required time delay.
The described devices are designed to be included in the positive power cable of the load. However, since the IRF7309 assembly contains transistors with a channel of both types, it is not difficult to adapt the timers to include in the negative wire. To do this, the transistors should be swapped and reversed by switching on the diode and capacitor (naturally, this will require corresponding changes in the printed circuit board drawings). It should be noted that with long connecting wires or the absence of capacitors in the load, pickups on these wires and uncontrolled activation of the timer are possible.
Timer circuit for five minutes |
If the time interval is more than 5 minutes, the device can be restarted and the countdown can be restarted.
After a short circuit SB1, the capacitance C1 starts charging, which is included in the collector circuit of the transistor VT1. The voltage from C1 is supplied to an amplifier with a large input impedance on transistors VT2- VT4. Its load is an LED indicator that turns on alternately after a minute.
The design allows you to choose one of five possible time intervals: 1.5, 3, 6, 12 and 24 hours. The load is connected to the AC mains at the start of the countdown and disconnected at the end of the countdown. Time intervals are set using a frequency divider of square wave signals generated by an RC multivibrator.
The master oscillator is made on the logical components DD1.1 and DD1.2 microcircuits K561LE5. The generation frequency is formed by an RC chain on R1,C1. The accuracy of the course is adjusted over the shortest time interval, by selecting the resistance R1 (temporarily, when adjusting it, it is desirable to replace it with a variable resistance). To create the necessary time ranges, the pulses from the output of the multivibrator go to two counters DD2 and DD3, as a result, the frequency is divided.
These two counters - K561IE16 are connected in series, but for simultaneous reset, the reset pins are connected together. Reset occurs using switch SA1. Another toggle switch SA2 selects the required time range.
When a logical unit appears at the output of DD3, it goes to pin 6 of DD1.2, as a result of which the generation of pulses by the multivibrator ends. At the same time, the logical unit signal follows the input of the inverter DD1.3 to the output of which VT1 is connected. When a logical zero appears at the output of DD1.3, the transistor closes and turns off the LEDs of the optocouplers U1 and U2, and this turns off the triac VS1 and the load connected to it.
When the counters are reset, zeros are set at their outputs, including the output on which the SA2 switch is installed. At the input of DD1.3, zero is also supplied and, accordingly, a unit is output at its output, which connects the load to the network. Also, in parallel, the zero level will be set at the input 6 DD1.2, which will start the multivibrator, and the timer will start timing. The timer is powered by a transformerless circuit, consisting of components C2, VD1, VD2 and C3.
When the toggle switch SW1 is closed, the capacitor C1 begins to slowly charge through the resistance R1, and when the voltage level on it is 2/3 of the supply voltage, trigger IC1 will respond to this. In this case, the voltage at the third output will drop to zero, and the circuit with the bulb will open.
With a resistance of resistor R1 of 10M (0.25 W) and capacitance C1 of 47 uF x 25 V, the device will operate for about 9 and a half minutes, if desired, it can be changed by adjusting the ratings of R1 and C1. The dotted line in the figure indicates the inclusion of an additional switch, with which you can turn on the circuit with a light bulb even when the toggle switch is closed. The quiescent current of the design is only 150 μA. Transistor BD681 - composite (Darlington) medium power. Can be replaced by BD675A/677A/679A.
This timer circuit on the PIC16F628A microcontroller is borrowed from a good Portuguese site for electronics. The microcontroller is clocked from an internal oscillator, which can be considered accurate enough for this moment, since pins 15 and 16 remain free, an external quartz resonator can be used for even greater accuracy in operation.
A kitchen timer will help you forget about undercooked and overcooked dishes, and a wide range of chronometers allows you to choose a timer for any kitchen style.
An amazing fact: a kitchen timer before its appearance in the house is not recognized as a primary need, but as soon as the hostess appreciates its benefits, the cooking process without it will seem like a real torment. Judge for yourself, even with an exceptional “sense of time”, it is impossible to absolutely accurately, down to a second, determine exactly how many minutes this or that stage of cooking lasts, whether it is boiling eggs or baking with your own hands. Forget about undercooked or overcooked meals, constantly standing “on guard” at the stove - once you have a kitchen chronometer, you will start to do more in the same period of time.
Electronic and mechanical options for timers are available in a huge range, differing in the appearance of the case and functionality. Finding the right model is not difficult. By the way, such a useful device can be presented as a gift.
Types of timers for the kitchen
It would seem that it could be easier to choose the right timer model. After all, this is not such a complicated device, in comparison with large household appliances, and you do not need to understand many of the little things and nuances associated with its operation. However, faced with a variety of models from dozens of manufacturers offered on the market, many buyers will simply start to run their eyes.
To help formulate for yourself the qualities that a kitchen timer should have, we suggest that you familiarize yourself with general information about common types of these devices.
Electronic timer
Typically, an electronic kitchen timer is implemented as a desktop electronic clock with detailed operating instructions. Such a chronometer most often runs on conventional batteries, sometimes on the mains, but in this case, the mobility of the device is lost. The compact model, thanks to its size, allows you to take them with you to another room, keeping it in your pocket. Thus, there is no need to constantly stay in the kitchen, waiting for the signal to complete the next stage of cooking.
Compared with the mechanical version, the main advantage of the electronic timer is the accuracy of the set response time - up to a second. On the other hand, you need to constantly change the batteries.
In general terms, the principle of its operation is similar to a mechanical watch or a spring. Most often, it is a knob, by turning which you set the response time of the device, while focusing on the gradient dial located around the rotary part of the mechanism. By setting the pointer in front of the desired value, the user immediately sets the device into action. The passage of a given period of time is notified by a sharp mechanical signal, often similar in sound to a bicycle bell.
Chronometers of this type are easy to use, do not require replaceable batteries for operation. As a rule, these are cheap and uncomplicated devices, however, some manufacturers offer rather elegant models, their external characteristics comparable to works of art.
Built-in timer option
Separately, we should mention the timers included in the design of more complex household appliances. It can be a hob, multicooker, toaster, food processor, etc. Often, the manufacturer makes the chronometer functionality separately, so that it can be used without turning on the main device. You can learn how to use the timer, built-in, for example, into a gas stove, from the attached instructions.
The built-in timer can be either mechanical or electronic. Its main drawback is the inability to carry it with you.
Unusual devices
Many manufacturers specializing in original technology offer devices that combine a timer mechanism and other functions that are no less useful during cooking.
- Timer with built-in thermometer. It is completed with a sensor located on a special needle, which can be immersed directly into the dish being prepared. With it, for example, you can track the degree of readiness of meat, fish and other products. When the set temperature is reached, the device will give a signal, which will avoid the situation when the already served dish is not quite in the condition that was expected.
- Egg timer. A very convenient device, immersed in water heated on the stove along with chicken eggs. It will notify you whether the eggs are cooked, to what extent readiness has reached (soft-boiled, hard-boiled, “in a bag”). The indicator is a special case material that changes color from prolonged exposure to high temperatures.
- Assistant for cooking spaghetti. The device measures the number of servings of pasta and reports the degree of their readiness.
Homemade timers
The kitchen timer has gained great popularity among radio amateurs who create all sorts of useful electronic devices in everyday life with their own hands. Due to the relative simplicity of the circuit diagram and a small number of parts, the timer is chosen as one of the very first self-assembled devices. As a case, it can use parts from old or non-working computer mice, watches, remote controls and other devices that would most likely end up in the bin, but have found a completely new purpose.
Although the appearance and functionality of such a kitchen timer cannot always be compared with a factory product, however, the value of a useful thing created by oneself is not at all in this.
Shape and material
In addition to handheld devices, there are many models that offer different layout options in the kitchen. It can be:
- wall models, most often combining the usual functions of a clock;
- desktop kitchen timer, which you can always keep at hand while cooking;
- devices with special fastening to vertical surfaces. For example, with a suction cup that allows you to attach the gadget to a wooden kitchen cabinet or to a tiled wall, or it can be equipped with a magnet for secure installation on the refrigerator door.
When choosing a specific timer model, be guided by the practicality of the material from which it is made, as the user often stains the device with his own hands, which are not always clean and dry during cooking. It is also important that the case is resistant to mechanical damage so that the user does not accidentally break the device or disable it.
Best of all, when operating small kitchen appliances, stainless steel, rubber and high-strength plastic have proven themselves.
Product design
The appearance of modern kitchen appliances is gradually losing its purely utilitarian features. When choosing a certain model of an assistant for the kitchen, much attention is paid not only to the practical properties and functionality of the device, but also to its external parameters, their compatibility with the interior of the kitchen and the design of other household devices in it.
As for such a device as an ordinary timer, in addition to its direct purpose, it often has a decorative function, emphasizing and complementing a certain kitchen style. Here are some tips from interior designers:
- if your kitchen style belongs to the modern direction or is close to the Hi-Tech style, it is better to look at electronic timers that have a large digital LCD display;
- for minimalist furniture, a small-sized device is perfect, the color and material of the body of which will be in harmony with the rest of the situation;
People involved in cooking know how easy it is to ruin a dish by being distracted by other things and forgetting to turn off the stove in time. Therefore, at the request of my wife, I was given the task of making a simple and easy-to-manage timer for the kitchen. Of course, this function is built into almost any mobile phone, but not everyone knows how to use it, and every time it is inconvenient to search and configure it in the mobile phone menu. Ideally, a small-sized device is required, which is controlled by a simple push of a button and does not contain scarce elements. In everyday life, 3-4 time intervals are usually sufficient, which are used most often. The search for a suitable circuit in various radio magazines did not bring results - the proposed timers were either rather difficult to manage, which could lead to an error when setting the countdown time by an unprepared user, or they were powered from the network, excluding their mobility, or more expensive than buying a ready-made device. In this regard, I developed a scheme devoid of all these shortcomings.
The operation of the device is based on the gradual charging of a capacitor connected to the input of the operational amplifier to a voltage at which the state of the output of the op-amp switches, which in turn controls the sound generator. One of the advantages of the device is that it does not have a power switch - just press one of the three switches to turn on and start the desired countdown interval. At the same time, the LED lights up, indicating that the timer is on and the time delay is in progress. After the set interval has elapsed, a continuous beep sounds. By pressing the same switch again, we turn off the device.
The basis of the device is a quad operational amplifier LM324, and three of its elements are separate timers, and the fourth element is a sound generator. By pressing one of the switches corresponding to the desired time delay, say, SA1 - 5 minutes, power begins to flow to the circuit, and the capacitor C1, connected in parallel with the switch contacts, ceases to be closed and begins to slowly charge through the resistor R1. Thus, at the moment of switching on, the potential at the inverting input of the op-amp is lower than at the non-inverting one, therefore, the output of the op-amp has the potential of the supply voltage. The inverting input of the sound generator on the DA1.4 element through the VD1 diode is at a high potential, which blocks its operation - the speaker is silent.
After the time required to charge the capacitor C1 through the resistor R1, the potential at the inverting input of the op-amp will exceed the value of the potential at the non-inverting one. In this case, a low potential will form at the output of the op-amp - the diode VD1 will be closed and the sound generator will start working. From the output 14 of the DA1.4 element, the signal generated by the generator, through the resistor R4 and the diode VD1, enters the base of the transistor VT1, to which the sound emitter is connected, an audible signal is heard. To turn off the device, you must press the switch SA1 again, which turns off the circuit from the power supply and simultaneously discharges the capacitor C1 - the timer is ready to work again.
The countdown time of the timer is determined by the values of the elements C1-C3 and R1-R3. With the specified values of these details, we will have the following time intervals: SA1 - 5 minutes, SA2 - 10 minutes, SA3 - 20 minutes. If desired, you can
change the exposure time of each of the timers by increasing or decreasing the values of the corresponding resistors and capacitors.
Establishing the device is reduced to the selection of the capacitor C4, which determines the tone, and the resistor R5 - the volume of the sound.
The printed circuit board was not developed, since surface mounting was used. Resistors MLT -0.125. Time-setting capacitors C1-SZ with the lowest possible leakage current, the rest are K73-17. Diodes VD1-VD4 - KD521A, replacement of the transistor VT1 - KT817A, B. Red LED HL1, you can use flashing
UL-506S11FD-FB, which will allow you to get the effect of timing. Switches SA1-SA3 - any small-sized. A small speaker with a winding resistance of 8 ohms is suitable as a sound emitter, you can use a small sound emitter from Chinese soft toys, measuring 12x10 mm. It is only necessary to achieve a sufficiently high sound volume, otherwise the timer may not be heard against the background of working household appliances. Power is supplied from a 6 V battery. A change in the supply voltage within 4.5 ... 12 V has almost no effect on the timer exposure time, while only the sound volume decreases.
D.Yu. Kibardin, Khmelnitsky RA2 "2010
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