We make a doorbell.
Doorbell on timer NE555.
The NE555 timer chip has become quite widespread in amateur radio designs; it is used to generate pulses with a wide range of durations. One of the options for using it is the doorbell diagrams below. The first circuit uses one timer chip on which a rectangular pulse generator is implemented. The circuit is powered by a 9 volt Krona battery. The bell is turned on by pressing the SB1 button.
The second circuit is implemented on two NE555 chips, i.e. has two sound generators. The frequency of the first generator is 1Hz, it is adjusted with a variable resistor R1. The signal of the second generator is modulated by the output signal of the first generator, the frequency is adjusted by variable resistor R2. The setting comes down to using resistor R1 to set the required switching speed from the first tone to the second, and using variable resistor R2 to set the desired sound tone. The sound of this call resembles the sound of a bigben. IN additional settings the device is not needed.
The circuit has a wide supply voltage range from 3 to 15 volts (NE555), or from 5 to 15 volts if we use the domestic analogue KR1006VI1.
An 8-ohm 0.5-watt dynamic head is used as a sound emitter.
The NE555 chip can be replaced with LM555 or the domestic analogue KR1006VI1.
Data on the KR1006VI1 microcircuit.
Pin assignment:
1 – general;
2 – launch;
3 – output;
4 – reset;
5 – divider control;
6 – operation;
7 – discharge circuit;
8 – power supply (+Up).
The main parameters of the KR1006VI1 microcircuit are as follows:
Rated supply voltage from 5 to 15 Volts.
Current consumption, no more than 15 mA.
Maximum load current up to 100 mA.
The minimum duration of the pulse generated by the timer is 20 μs, the maximum is determined by the parameters of the external timing elements (ti = 1.1 RC).
Switching schemes.
a – in standby mode;
b – in autogeneration mode.
A simple doorbell.
And another version of a simple doorbell circuit using two germanium transistors powered by a 220V network. In this way, with recalculation of R2 and selection of the zener diode to the desired stabilization voltage, it is also possible to power the above-described circuits in order to eliminate the use of replaceable batteries (batteries or accumulators).
I present to your attention a doorbell circuit that was assembled many years ago and has been in use for the same amount of time. It would be more correct to call this device: “Waste into income!” Because what it was made from was literally lying underfoot. This was during Soviet times. I was working at a small PBX at the time and had a lot of free time that I wanted to convert into money... Then I began collecting electronic calls based on this scheme and inserting them into . The installer of the city automatic telephone exchange willingly helped me with the implementation, making his own profit from it. The device imitates the sound of a bouncing ball. All characteristics are adjusted by selecting the capacitance of the capacitors and adjusting the variable resistor.
Electrical circuit diagram
Once assembled without errors, it starts working immediately. Power supply is possible from a 12 volt DC source (then diodes D1-D4 and capacitor C4 are excluded). The ringing pulses of an alternating current telephone exchange are 110 volts 25 hertz - in this case, the capacitance of capacitor C4 should be 1 microfarad per 400 volts.
AC voltage 220 volts 50 hertz, when used as an apartment bell (in this case, the capacitance of capacitor C4 should be 0.5 microfarads at 400 volts). The device was assembled using pieces of foil getinax, which were cut on a machine (Skillful hands) with a small circular cutter. I used one board as a conductor for drilling holes, but it can also be assembled using wall-mounted installation.
Parts used
Transistor T1 - mp25-26, T2 - kt605 or p307-309, but p605 works better, diodes D1-D4 - D226, but others are possible, although D226 gave better results. Capacitors C1-0.1 C2-0.05, trimming resistor - 47k, C3 - 100 microfarads at 100 volts. The telephone capsule was used as an emitter, but only very old ones (large diameter).
The use of a Czech capsule with a resistance of 50 ohms gave very good results, but it has one feature - to achieve good volume, you need to remove the plastic plug from the side of the contact screws, under which there is an adjustment screw and, having turned on the device, use a small screwdriver to make adjustments, unscrewing and tightening screw to achieve maximum sound volume.
Warning! If you are going to use this device as a doorbell, do not set it up by connecting it to a 220 volt network! You may be exposed to high voltage! Set up by connecting to DC 12 volts, only then connect the mains voltage.
After the doorbell died for a long time, I dug it up on the mezzanine old phone, tore this electronic bell out of it, packed it in a box of cotton swabs, and now it continued its service above the door. Author of the project - Wolf9405.
Discuss the article DOORBELL FOR BEGINNERS
Sometimes, to make an electronic craft, it is enough to find the necessary radio components. So the source for making the electronic bell was parts from a broken handset of the Comax intercom.
How to make a doorbell with your own hands
In the process of putting things in order, a broken tube of the Comax intercom was found, but before it went into the trash bin, the electronic part was examined for the presence of useful radio elements. Moreover, now usefulness is easy to determine using the Internet. So, the marking of one of the microcircuits in the DIP8 package was HT2811 and its datasheet reported that this was a doorbell microcircuit! Well, the microcircuit was found on time, just when the call was needed. Production proceeded according to the following scheme.
1. The description of the microcircuit shows all the characteristics of its connection and even provides a typical circuit diagram. Therefore, all parts of the HT2811 harness were carefully removed from the board using a soldering iron with suction. The output stage transistors were removed from the board of the disassembled cathode ray monitor.
2. Since the performance of the parts was unknown, then electronic circuit was assembled on a solderless breadboard. Tests showed the functionality of the call. At the same time, the characteristics of the call were taken. When connecting an 8 Ohm speaker without an output transformer, the current consumption of the circuit did not exceed 60 mA at peak, the average current during the chime was 25 mA. Power was supplied from two 1.5 Volt batteries placed in a container from a battery LED garland. Watch a video.
3. Electronic components are assembled according to the circuit on the “patch” of the breadboard for soldering and the wires of the button, power supply and sound output are brought out.
4. Any amateur radio design will be complete if it is placed in a housing. The issue with the case was resolved simply; an ADSL modem lying around unnecessarily was used as the case. The electronics, there were also interesting details there;), were removed. On one side, the ventilation holes were widened and a speaker was installed on the inside using hot-melt adhesive. The speaker was removed from system unit computer 486 series. See photos and videos.
Holes widened Speaker fixed Bell board HT2811In order to arrange convenient access to the apartment, you should understand the doorbell diagram. Today there are many models of such devices, but at the same time general principle their work remains almost the same. Let's look at how to properly install and repair a bell if necessary.
Depending on the type of doorbell, the connection method may differ significantly
Device Features
In each house, a whole list of additional devices is installed at the entrance to create comfortable conditions. One of them is the doorbell. Its direct purpose is to notify people in the apartment that guests have come to them.
Every person is superficially familiar with the bell device. A call button is attached to the outside of the home; a speaker is installed inside the apartment, which picks up the signal from the button and transmits it in the form of a sound alert. This is how the simplest models work. IN modern devices functions are significantly expanded up to the transfer of video images online to Cell phones. Depending on personal preferences, the available budget and the requirements of the owners, you choose how to make a doorbell: in the form of a simple addition or with all the available auxiliary capabilities.
Very often, home owners plan to install a doorbell with their own hands, so it is important to understand the circuit diagram and connection method. To do this, first of all, you should consider the main models existing on the modern market.
A modern doorbell with a video peephole will ensure home security
Types of calls
Today, the range of products in this group is huge and does not stop expanding. With the development of technology, not only are they improving external characteristics calls, but also their functionality.
Installation of a doorbell can now be done in a matter of minutes, since manufacturers have previously provided for the lightweightness of the device and ease of use.
There are the following types of doorbells:
- Wired. This scheme is already becoming obsolete. All elements are connected to each other by cable, which somewhat complicates the connection process. The instructions should include a diagram to assist with installation.
- Wireless. Instead of a cord, a circuit is used to transmit a radio signal and receive it through an antenna. The only wire may be the power supply cable.
- Sound. The signal is a sound notification: a call, a melody, a musical composition, a voice recording.
- Video calls. Connecting a doorbell with a video camera allows you to see what is happening behind the door. Some models are activated only when you press a button, while others can turn on based on a motion sensor or continuously broadcast a picture.
- Intercoms. Allows you to transmit voice messages both inside the house and outside. Can be combined with a video system.
Types of doorbells depending on the principle of operation
Connection rules
Connecting the device is carried out in several stages, but before installing the doorbell, you need to carefully consider its location. Please note that the sound of the signal should be clearly audible in all rooms, this is especially true for private homes. Some models can be equipped with multiple speakers that can be placed in different parts of the house. And if there are several inputs, you can purchase an additional call button.
So, how to connect a doorbell:
- Wireless. The wiring diagram for such a do-it-yourself doorbell is the simplest. To begin, set the call button to convenient place. Then determine where to hang the speaker, taking into account the range of the device and possible obstacles to the signal. The elements are attached with bolts or adhesive tape.
- Wired. Here you need to figure out in advance exactly how to connect the doorbell. Please note that you will have to run a wire connecting both devices, so think about the optimal path in advance. It is advisable to disguise it in the wall, under a suspended ceiling or baseboard. A wire goes from the button to the speaker, and from there to an outlet or directly to the power supply. For work safety, first turn off the voltage in the distribution panel. The connection principle itself is as follows: first, the wires for connecting the device (phase and neutral) are brought out, the supply wire is inserted into the housing of the bell speaker and secured to the terminals. The second part is connected to the call button, power is supplied to the bell and its operation is checked.
- Video calls. The main difference is the additional placement of a camera above the door and a screen for receiving images.
Connection diagrams various types doorbells
Repair
If certain problems arise after installation or during operation, you need to know how to fix the doorbell yourself. Most often, the cause of failures is contact separation. To fix the problem, you need to look at the locations of the key connections. This could be a button or a speaker inside the house. Sometimes it is enough to tug the wires and the call works normally again. It is much worse if the leading cable is broken. Then it needs to be replaced or soldered.
If you use the doorbell for a long time, problems with the contacts may occur.
There may also be problems with nutrition. Then you need to check and repair the power supply and input plugs yourself. In wireless models, do not forget to change batteries on time and monitor the condition of the battery.
This issue is especially relevant for outdoor devices in areas with a cold climate and sudden temperature changes.
If you understand the bell device, you won’t have any problems installing it yourself. In addition, if problems arise, you can easily fix it without requiring outside help.
A two door bell with indicator is well suited for use in a home where there are two gates or doors that are located far apart. He helps the person inside the house by different sounds and number indication, determining which doors the visitor is standing near. This saves time and effort by not having to check both doors. On the site electroschematics.com we found this very interesting diagram of a homemade doorbell that functions in such a way that different sound signal, depending on which button SW1 or SW2 is pressed. This is necessary for those who have 2 doors that can be called. With such a call, it is immediately clear which one is being called.
The alarm will only be activated for 1 second and the display will turn on for 1 minute and then turn off automatically to save energy. When powered by 220 V, this is not critical, but for a battery-powered bell it is very useful. The backup power supply is not shown in the diagram - you can adapt it yourself. Simply remove the transformer along with the diodes and filter capacitors and replace it with a 9-volt battery.
Electronic doorbell circuit
Schematic Parts List
- Battery or 220V/6V transformer
- D1, D2, D3, D4 - 1N4001
- C1 - 4700 uF
- C2 - 470 uF
- LM7805
- IC1, IC2, IC3 - LM555 or NE555N
- IC4 - 74LS02
- IC5 - 74LS47
- T1, T2, T3 - 2N3904
- R1, R3, R5, R7, R8, R10 - 1K
- R2, R4 - 10K
- R6 — 100k
- R9 - 600K
- 11 to R17 - 330 ohm
- R18 — 100k
- R19 – 5k
- C3 - 100 uF
- C4, C6, C8 - 0.01 uF
- C5, C7 - 10 µF
- C9 - 100 uF
- 7-segment display with common anode
- Piezo emitter
The circuit consists of mono- and astable multivibrators. You can change the frequency of the signal reproduced by the self-oscillating multivibrator by turning potentiometer R18. The call volume is affected by the resistance of resistor R19. The power consumption of the circuit is 0.2 watts. Current consumption during a call is 50 mA. Printed circuit board was not developed - everything was assembled on a breadboard.
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