Good afternoon. My first article. I don’t claim authorship, I’m just sharing my assembly experience. This is a pic16f84 kitchen timer with a full keyboard and a four-segment display. Original article (Author - Allex).

The writing of this article was prompted by the absence printed circuit board in the original there is a small error with resistor R3 (you need to put 100 ohms instead of 100 kOhm). So what do we need:
1. 7805;
2. Two ice indicators with a common cathode Rl-D5613 (although I recommend re-wiring the board for Rl-D5611 indicators);
3. 1 5 Volt beeper with internal generator;
4. 5 resistors per 10 kOhm;
5. 1 resistor per 100 Ohm;
6. 3 resistors per 100 kOhm;
7. microcontroller pic16f84;
8. 12 buttons (the same type as those found in mice, only with long buttons);
9. Quartz at 4 MHz;
10. 2 capacitors at 33pF;
11. 1 capacitor at 0.33 mF;
12. 1 capacitor 0.1 mF;
13. Power contacts from a crown battery;
14. Case Z-19 (if desired, you can take a different type with a battery compartment);
15. Microcontroller socket for 18 legs.

We transfer the printed circuit board to PCB using the LUT method and etch (after etching, some of the tracks were torn, so the device did not work immediately, after correcting the breaks, the device started working).
We flash the microcontroller. In the ICprog program we set all fuses to “removed” and in the drop-down list to “HS”.

We assemble the device according to the diagram:

14 leg plus. 5 leg minus. To the 4th leg there is a 10 kOhm resistor and to the power supply plus. To the 15-16 leg quartz and capacitors and to minus.
Next, we mount it into the case, cut out a window and glue the plexiglass, and also cut out holes for the buttons.

View of the finished device.

Disadvantages of the device:
In this implementation, protection of the PCB from dirt is not thought out; it is worth installing either covers (caps) on the buttons, or buying a ready-made keyboard.
It is also worth adding a switch to the battery, since at 9V it consumes up to 50 µA, and when the battery is dead at 5V, only 15 µA.

Pros:
Low power consumption, up to 40 hours on one battery.
Small sizes.
Ease of implementation. Few details.
Doesn't need any setup.
A full-fledged keyboard (no need to explain to your wife how many times to point where).
Availability of hours.

I am attaching the firmware and software of the device.
▼ 🕗 12/07/10 ⚖️ 824.35 Kb ⇣ 118 Hello, reader! My name is Igor, I'm 45, I'm a Siberian and an avid amateur electronics engineer. I came up with, created and have been maintaining this wonderful site since 2006.
For more than 10 years, our magazine has existed only at my expense.

Good! The freebie is over. If you want files and useful articles, help me!

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Thank you for your attention!
Igor Kotov, editor-in-chief of Datagor magazine

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Kitchen timer: existing varieties and subtleties of choice

Are you planning to buy a kitchen timer? Then I propose to figure out together what types it comes in, and what you should pay attention to when choosing the model you like. It will also not be superfluous to consider specifications specific offers from well-known manufacturers.

Kinds

A timer installed in the kitchen can facilitate the cooking process and improve its results, because thanks to it:

• You won't miss the exact moment of cooking, the device will warn you that enough time has passed;
• You will not have to At the same time, being on duty over the stove yourself will allow you to do other things around the house.

The following types of timers are capable of performing such simple, but very important functions for the kitchen:

Mechanical

A mechanical kitchen timer has a round dial and works on the principle of a regular watch:

• Starts up clockwise;

• Performs countdown to the set point in time.

The described design features provide this type of devices under consideration with a number of advantages, among which a special place is occupied by:

1. Low price. In fact, you only have to pay for the spring mechanism. The cost can rise only due to the intricacy of the body part, its decor and shape;
2. No batteries. A power supply that runs out at the wrong time can become a significant problem. Such a situation is excluded here;
3. Simple operating instructions. You just need to turn part of the device to the desired position and that’s it;

But there are also disadvantages to such a device:

1. Limited running time. As a rule, mechanical timers can be wound for no more than sixty minutes. For simple dishes this is quite enough, but it will be more difficult to prepare something more refined;
2. Relatively large error. Almost all cheap samples suffer from this disease.

Manufacturers offer many models of the most varied appearance, although internally they differ not so strikingly from each other. Let's look at some of them:

The prices in the article are current in the summer of 2017.

• Model Bottle:

• Model Lemon:

• Model Cylinder:

Electronic

With the development of technological progress, timers began to change, as a result of which electronic models appeared. The presence of electronics in the device provides a number of important and undeniable advantages, among which the most worthy of mention are:

1. Availability of display indicating the time remaining until the signal. There is no need to guess by the divisions how many minutes the dish still needs to be cooked; clearly visible numbers will conveniently provide you with all the necessary information;
2. High accuracy. Where the spring may have an error, the electronics accurately measure the specified amount of time;
3. Longer timing. Typically reaches 99 minutes;
4. Compact dimensions. A small device can be easily installed not only on any horizontal, but also vertical surface;

1. Possibility of additional functions. A clock, a barometer, a thermometer - all this can complement the timer and make it even more useful in the kitchen.

There are also disadvantages that you have to put up with in order to have such a useful assistant. These include:

1. Relatively high cost. The presence of electronics not only makes the device better, but also more expensive;
2. Dependency on batteries or mains electricity. Electronic device needs appropriate nutrition.

Among the offers from manufacturers are the following representatives of electronic kitchen timers:

• Model Tasty Colors:

• Model Presto:

• Model GEFU:

Subtleties of choice

Choosing a timer for the kitchen is not so easy, despite the fact that it is not an essential item. It is worth considering it separately here:

• Design features. That is, how it will look indoors;
• . This directly concerns the operational properties of the device.

Let's look at them in more detail:

Design features

• Modern styles. Preference should be given to electronic models of steel color or shades that are in harmony with the overall kitchen interior;

If your kitchen professes minimalism, then the timer should not stand out from the general background. For this, I recommend choosing a small copy of the same color as the furniture.

• Classic styles. Samples in the form of vegetables, fruits or kitchen utensils will look great.

Ease of use and practicality

• Presence of a magnet allows you to conveniently attach the timer to the refrigerator or oven;

If your kitchen is dominated by wood or its cheaper substitutes, then it is better to give preference to a model with a suction cup. In this case you will have more possibilities to place it.

• Housing material must be impact resistant. The device can easily suffer mechanical damage in the cooking area.

Conclusion

You have learned how an electronic kitchen timer differs from a mechanical one and how to choose them correctly. The video in this article provides additional information. You can ask questions in the comments.

This device will be useful to anyone who has to cook constantly, and will reliably protect your kitchen from excessive amounts of smoke. This device, as the name suggests, is a kitchen timer. It is designed to count intervals when preparing various dishes. The timer has several keys with which you can easily set the time from 1 minute to 99 hours. The countdown starts automatically 3 seconds after setting the time. Thanks to the loud beeper, you will definitely hear when the dish is ready. The device is assembled based on the ATMega8 microcontroller.

Description of design

The heart of the device is the microcontroller U1 (ATMega8) with a quartz resonator X1 (16 MHz) and a string of two capacitors C1 (22 pF) and C2 (22 pF). Stabilizer U2 (7805) with capacitors C3 (100 µF) and C4 (47 µF) stabilizes the 5V supply voltage necessary for the correct operation of the microcontroller and related components. A voltage of 7-12V is supplied to the Zas connector. If you have a power supply with a voltage of 5-6V, you can exclude the voltage stabilizer from the circuit. Buzzer B1 and display anodes W1 are controlled by transistors T1 - T5 (BC556), with resistors R1 - R8 (3.3 kOhm), R17 (3.3 kOhm) and R18 (3.3 kOhm). Resistors R9 - R16 (330 ohms) limit the current through the display segments. The Prog connector and one R pin are used to connect the programmer. The timer keyboard is connected to the Sw connector.

Manufacturing

A drawing of the printed circuit board for the device is in the archive at the end of the article. Installation of parts begins with soldering two jumpers. Then all resistors and other elements are installed in order from smallest to largest. Quartz X1 must be “low” - it is installed under the display - otherwise it simply will not fit there. The B1 buzzer can be soldered onto the board as shown in the photos, but it was later discovered that the sound was too quiet after closing the case (despite the holes drilled into the case). It is better to glue the buzzer to one side of the case (as shown in the last photo) and connect it with wires to the board. The keyboard consists of 5 non-latching 12x12mm buttons directly on the front of the case, so that their pushers are slightly above the surface of the case. For this device it is good to use as a power supply Charger for a phone, due to its light weight and size.

List of radioelements

Smart indicator

We will make our own indicator, of any shape, from SMD LEDs. Compact - minimum size 20x20 mm with a thickness of only 2 mm. Low power consumption - 1-10 mA in operation, 5 µA in sleep mode. Independent control of each LED via one wire. Brightness control - more than 100 brightness levels. Up to 100 LEDs in an indicator, with any location on the board. Possible designs - two scales of 8 LEDs and 4 service LEDs; indication of cardinal directions - 8 LEDs in a circle and 4 service ones; clock - 12 LEDs in a circle; matrix 8x8 LEDs.

Li-ion battery discharge controller

This mini device is necessary for protection li-ion batteries from deep discharge. The circuit automatically turns off the battery when the voltage drops below 2.9V. Very low current consumption - only 500 nA. The maximum consumer current is 2A. Reliably protects your battery from overdischarge. The board size is only 10x6 mm.

UV index and temperature meter

Are you going to the sea? Take this device with you. With its help, you will never get sunburned and will tan correctly - an accurate measurement of the instantaneous and accumulated ultraviolet radiation index. You will know whether the sea has warmed up - accurate measurement of water temperature using a K-type thermocouple. How hot is it outside - measuring the air temperature. It will also be useful to you at the dacha - proper preparation of shish kebab. Miniature size 35x45x18, built-in battery, as well as a lot of other useful functions.

Course Overview

Since you have come to this page, then you do not yet have enough experience to make complex devices on microcontrollers. We invite you to take a young fighter course and expand the horizons of your knowledge in microelectronics. All you need to do is make all the devices offered here and master all the theory associated with them. At the end of the course, you will be able to independently design devices of medium complexity, program various microcontrollers, understand what modules various devices consist of, and what is needed to develop your own device.

In this article we will look at everything in detail key points course, we will justify the order of the devices, explain why they should be made exactly this way and why they all need to be made.

Dwelcome to a fascinating worldmicroelectronics!

The first issue of the radio magazine was published in 1924. Even then, there was interest in the manufacture of radio-electronic devices at home. Using a soldering iron, wires, and later on PCB, it was possible to make a full-fledged complex device. It was very difficult, only a few understood in this area.

Now almost every schoolchild can independently make excellent quality printed circuit boards at home. Assemble a modern device on them, the functions of which are not inferior to those sold on the market. All this became possible thanks to the advent of computers and the development of the Internet. Almost every device these days is made using . They allow you to breathe life into a device, solve complex problems using programming, and receive and display various data.

Can this be done using microcontrollers? How to do

Experienced housewives measure everything by eye and feel the time with their “internal” clock, but people tend to fall into thoughtfulness and get distracted by other things. It often happens that even experienced housewives turn pies lovingly prepared for baking into inedible carbon. The result is a spoiled mood, wasted time and disruption of planned plans. A simple kitchen timer on a widely used microcontroller will help you avoid this situation. ATtiny2313 Atmel company.

When developing the timer, the task was to use a minimum number of parts, ease of control, ease of repetition of the device, and the ability to power the timer from either three AA (LR6) 1.5 V batteries or from an external adapter.

Features and main characteristics of the timer:

1. Timer setting time from 1 to 90 minutes.
2. Sound alarm for turning on and off the timer.
3. Sound signaling of the end of the set time.
4. Forced shutdown of the timer before the set time has expired.
5. Automatic switching off of the timer after 10 s after turning it on if, after turning on the timer, the delay time was not set or the time countdown was not started.
6. The device is powered by both three batteries and an external adapter with a voltage of 7 to 10 V.
7. The current consumption of the timer in the off state is several times less than the self-discharge current of AA batteries.

Timer operation algorithm

The timer is activated by pressing the encoder button. The minimum possible exposure time of 1 minute is displayed on the indicator. By rotating the encoder knob to the right, the dwell time increases, and when rotating the encoder knob to the left, the time decreases, starting from 90 minutes. The timer will turn off on its own if the start button is not pressed within 10 seconds after setting the time. To start timing, you must press the encoder button again. In this case, the timer begins counting the set time, and on the indicator of units of minutes with a period of 1 s the decimal point will blink, indicating the countdown mode. After the set time has expired, the number 0 will appear on the timer indicator and 5 tones will sound. After this, the number 0 will go out, and the decimal point will blink for another 10 s. After this time has elapsed, 5 tones will sound again as a reminder and the timer will turn off. You can forcefully stop the timer at any time by pressing the encoder button.

Diagram, design and details of the timer

The schematic diagram of a kitchen timer is shown in Fig. 1. The “brain” of the device is a microcontroller (MK) IC1 type ATtiny2313 from ATMEL in a DIP20 package. Microcontroller ATtiny2313 clocked from an internal oscillator with a frequency of 8 MHz with the prescaler turned off by 8.

Picture 1

To control the timer, an incremental encoder with a Bourns button is used RES12-4220F-S0024.As an indicator of the set time, a dual 7-segment red indicator with a common cathode (OC) from the company is used SENIOR SEC5244WS.

It is also possible to install indicators with a common anode (CA) in this timer without changing schematic diagram and fees. To do this, when programming the MK, it is necessary to use another firmware developed by the author specifically for indicators with OA. A buzzer (Magnetic Buzzer) type is used as a sound detector KX-1205 from King State. The timer uses SMD resistors and capacitors of size 0508.

The timer is assembled on a single-sided printed circuit board made of foil PCB measuring 48x56 mm using several jumpers, which are located on the installation side of the parts. A drawing of the timer printed circuit board for LUT is shown in Fig. 2.

Figure 2

To power the timer from an external adapter, a 78L05 linear integrated stabilizer in a SOP-8 package is used. The diagram of the additional board for the external adapter is shown in Fig. 3, and the drawing of the printed circuit board for the LUT is shown in Fig. 4. Its dimensions are 48x66 mm. The battery compartment for three galvanic cells is made of foil PCB. And his back side- This is an additional board for an external power adapter. If there is no need to power the device from the network, then there is no need to assemble an additional board, but instead, install a board made of foil fiberglass of the same size.

Figure 3

Figure 4

When assembling the timer board, the first step is to install the appropriate jumpers. After flashing the microcontroller, the timer assembled from serviceable parts does not need to be configured. Due to the presence of water and fat vapors in the air during cooking, I recommend that the timer boards be washed with alcohol after assembly and coated with acrylic varnish.