Water level indicator in the room. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Indicators, detectors

 Comments on the article

The water level indicator (IUV) is a device that signals the appearance of water on the floor in the apartment or when a critical liquid level is reached in the sink, bathtub, etc. when they are filled. IUV can also be used as an indicator of emergency water rise in sewer pipes or storm drains when they become clogged.

The IUV emits a tone signal along with a flashing light signaling for 60 seconds, and then goes into standby power saving mode. When the power is turned on, if the liquid appearance sensor is already soaked (in the liquid), a short alarm sounds.

IPM (Fig. 1) consists of:

• autonomous power supply (GB1 batteries);
• liquid appearance sensor (probes) B1;
• reset circuits C5-R4;
• resistive voltage divider R1-R2 with anti-interference capacitor C1.
• the first one-shot timer on the elements DD1.1. C2. R3, VD2, VD3;
• the second one-shot timer - DD1.2, C6, VD6, R8 with a trigger device on the elements VT2, R5;
• logic element 2OR - VD4, VD5, R6;
• current key on a field-effect transistor VT1 with a combined load on the elements HL1, HL2, C4 and an active buzzer A1 with a built-in generator and emitter in one housing.

When the SA1 "Power" toggle switch is closed, the IUV is set to standby mode and is in this state until the resistance of its sensor is high, i.e. dry sensor. When water (any conductive liquid) appears near the sensor contacts, the resistance between the contacts decreases, the IUV is triggered and is in alarm mode for 1 min (generates a light and sound alarm signal). The operating time of the light and sound alarm (alarm mode) is limited to save battery life. A triggered and "silenced" IUV during repeated leaks, when the sensor first dried out and then got wet again, goes into alarm mode again, etc. (up to turning off the power).

When the power is turned on, capacitor C5 is charged. The current flows through the circuit: + "GB1 - SA1 - C5 - R4 - common wire. While the capacitor is not charged, there is a logical level "1" on its "-" plate, which sets the timer-one-shot DD1 at the input R through the VD1.1 diode to the initial (zero) state. 2) single vibrator timer DD2 If the probes of the sensor are dry, then from the divider R11-R1.2 to the information input D (pin 1) DD2 a logical "9" is supplied. DD1.2 does not start, and its direct output (pin 0) is "1.2".

Thus, both single vibrators (DD1.1 and DD1.2) are set to their original state (on the terminals! and 13DD1-"0"). The inputs (anodes VD4. VD5) of the logic element 2OR receive "0". therefore, at the gate VT1 - low potential, removed from the resistor R6. Transistor VT1 is closed, the combined load in the drain circuit VT1 (elements HL1. HL2. C4, A1) is de-energized. The IUV is in standby mode.

When the liquid closes the contacts of the probe, due to the low resistance of the liquid, the voltage across the divider R1-R2 increases, and a high level is set at the input C (pin 3) of DD1.1. The first one-shot is started. At the direct output (pin 1) of DD1.1, "1" appears, which, through the diode VD4, enters the gate VT1, it opens, and the resistance of the drain-source junction VT1 decreases sharply (to a few ohms). The voltage from the battery GB1 is supplied to the load. Flashing LEDs HL1, HL2, periodically turning on, control the operation of the active buzzer A1. Capacitor C4 connected in parallel with buzzer A1. does not allow him to completely interrupt the work during pauses in the glow of the diodes. Thanks to this mode of operation, the sound of the buzzer becomes pulsating, with a noticeable "deviation" of the frequency, and more shrill.

The load is switched on for the time determined by the shutter speed of the first one-shot, i.e. while "G" is present at the direct output of DD1.1. Due to this "1" capacitor C3 is smoothly charged through the resistor R2. After 60 s (the time is determined by the C2-R3 circuit and can be calculated using the approximate formula t * 0,7-R3-C2) C2 will charge up to half the supply voltage plus the voltage drop across the silicon diode VD2 (about 0,7 V), which is equivalent to the appearance of "1" at the input R DD1.1. Trigger DD1.1 .1 is reset (on its output "0" is set to "2" again), and C3 is quickly discharged through the diode VD1.1. preparing the single vibrator for the next cycle of work. In other words, a 60-second pulse of positive polarity is formed at the direct output of DD4, which, through the diode VD1, enters the gate VT1 and opens it. Diodes VD2, VD1.1 "organized" in the mounting OR and expand the input "Reset" DDXNUMX.

If IUV is turned on at the moment when the probe is already soaked, then the positive polarity setting pulse through the discharged capacitor C5 is fed to the gate VT2, opens it. and a positive voltage drop from the VT2 drain is fed to the sync input C (pin 11) of the second one-shot. "1" is supplied from the divider R2-R9 to the information input D (pin 1.2) DD1, the one-shot starts, and "1.2" is set at the direct output of DD1.

The second single vibrator on DD1.2 works similarly to the first one and, at startup, generates a pulse of positive polarity with a duration of 1.3 s. From the direct output DD1.2, this pulse is fed through the diode VD5 to the gate VT1. Transistor VT1 opens and passes current through the source-drain channel to the load (HL1, HL2.A1). This shortened signal indicates that the sensor "detected" an emergency, but, most likely, the probe simply was not wiped (did not dry) after the previous accident. When IUV power is turned off, capacitors C7 and C3 are discharged through closed contacts SA1 and resistor R7, preparing IUV for re-enabling.

The resistance between sensor contacts immersed in water (conductive liquid) depends on the distance between them. The smaller the distance between the contacts, the lower the resistance. In IUV, this distance is fixed (10 mm).

Details. Resistors OMLT-0,125 are used in IUV. Capacitors C1, C3 - ceramic, KM; the rest are oxide. K50-35 or foreign production. Diodes - any silicon for example, KD503, KD510, KD5137KD520 ... KD522. Field-effect transistor VT1 can be replaced with KP501 with any letter index. Toggle switch SA1 - small-sized MTS-102 or extra small-sized SMTS-102. Nest XS1 - type SNTs-3,5 with nut fastening. The IUV uses a K561 series chip, which, when finalizing the printed circuit board, can be replaced by 564TM2. Block A1, with a slight decrease in the volume of the buzzer, can be replaced by TR1205-y (with a nominal operating voltage of 5 V and a current of 20 mA). As LEDs HL1. HL2 can apply almost any flashing. Pairs pair well: ARL-5013URC-B L-56BYD (yellow), as well as L-5013LRD-B and L-56BRD (both red). The resistance of the high-resistance resistor R6 is not critical and can be from 220 kΩ to 2,2 MΩ.

Installation of IUV should be carried out with a soldering iron with a grounded tip or low-voltage one. For ease of operation and configuration, transistors VT1, VT2 and the DD1 microcircuit can be installed in panels ("sockets") with a pitch between pins of 2,5 mm. 3-pin sockets for transistors can be made from a large socket for a microcircuit, for example. 14 pin.

Most of the IUV parts are placed on a printed circuit board with dimensions of 38x37 mm (Fig. 2) made of one-sided foil fiberglass. The thickness of the board is not critical and can be 1,5...2.5 mm. 4 mounting holes 02,7 m are drilled in the board for M2.5 screws. The remaining holes (for electronic components) are made with a drill with a diameter of 0,9 mm.

The board is installed in a plastic case of suitable dimensions, for example, in a rectangular soap dish measuring 100x60x30 mm. A design option for a false panel for such an IUV case is shown in Fig.3.

In the top cover of the housing, holes are drilled for the load elements, the XS1 socket and the screws (with a countersunk head) for fixing the board. Paper false panel. printed on a color printer, glued with PVA glue to the top cover of the case. After drying, the false panel is protected from moisture with a wide strip of adhesive tape.

Assembled without errors, IUV usually does not require tuning. The operating time of single vibrators can be adjusted by selecting resistors R3 and R8, respectively. The resistance of these resistors can be selected in a wide range - from 10 kΩ to 1,5 MΩ (and even more when using foreign-made oxide capacitors with low leakage currents).

Sometimes, in order to work in conditions of a high level of interference created by electrical appliances (tested with an air ozonizer), it is recommended to reduce the resistance of resistors R1 and R2 to 12 and 120 kOhm. This will increase the noise immunity of the IUV with a slight increase in the current consumption when the sensor is wet. An additional increase in noise immunity gives an increase in capacitance C1 from 0,22 to 2,2 μF (KM-ba) or a decrease in the length of the cable (twisted pair) connecting the probes of the sensor with the IUV case. Capacitor C1 in any case must be non-inductive (for example, ceramic).

Standby current IUV does not exceed 0,5 μA (with a dry sensor), 50 μA - with probes in water and 20 mA - when the load is in alarm mode.

Author: A. Oznobikhin, Irkutsk

See other articles Section Indicators, detectors.

<< Back

Latest news of science and technology, new electronics:

A New Way to Control and Manipulate Optical Signals 05.05.2024

The modern world of science and technology is developing rapidly, and every day new methods and technologies appear that open up new prospects for us in various fields. One such innovation is the development by German scientists of a new way to control optical signals, which could lead to significant progress in the field of photonics. Recent research has allowed German scientists to create a tunable waveplate inside a fused silica waveguide. This method, based on the use of a liquid crystal layer, allows one to effectively change the polarization of light passing through a waveguide. This technological breakthrough opens up new prospects for the development of compact and efficient photonic devices capable of processing large volumes of data. The electro-optical control of polarization provided by the new method could provide the basis for a new class of integrated photonic devices. This opens up great opportunities for ... >>

Primium Seneca keyboard 05.05.2024

Keyboards are an integral part of our daily computer work. However, one of the main problems that users face is noise, especially in the case of premium models. But with the new Seneca keyboard from Norbauer & Co, that may change. Seneca is not just a keyboard, it is the result of five years of development work to create the ideal device. Every aspect of this keyboard, from acoustic properties to mechanical characteristics, has been carefully considered and balanced. One of the key features of Seneca is its silent stabilizers, which solve the noise problem common to many keyboards. In addition, the keyboard supports various key widths, making it convenient for any user. Although Seneca is not yet available for purchase, it is scheduled for release in late summer. Norbauer & Co's Seneca represents new standards in keyboard design. Her ... >>

The world's tallest astronomical observatory opened 04.05.2024

Exploring space and its mysteries is a task that attracts the attention of astronomers from all over the world. In the fresh air of the high mountains, far from city light pollution, the stars and planets reveal their secrets with greater clarity. A new page is opening in the history of astronomy with the opening of the world's highest astronomical observatory - the Atacama Observatory of the University of Tokyo. The Atacama Observatory, located at an altitude of 5640 meters above sea level, opens up new opportunities for astronomers in the study of space. This site has become the highest location for a ground-based telescope, providing researchers with a unique tool for studying infrared waves in the Universe. Although the high altitude location provides clearer skies and less interference from the atmosphere, building an observatory on a high mountain poses enormous difficulties and challenges. However, despite the difficulties, the new observatory opens up broad research prospects for astronomers. ... >>

Random news from the Archive Laser interceptors will protect the Earth from asteroids 02.04.2012 Engineers at the University of Strathclyde in Glasgow are developing innovative laser technology designed to combat the asteroid threat. Researchers have discovered the possibility of using a group of relatively small satellites armed with lasers to deflect asteroids whose trajectory intersects with the Earth. A link of laser interceptors solves the problem of powerful impact on a small or medium-sized asteroid without the use of a huge spacecraft. Scientists propose sending a small satellite to the asteroid with a high-energy laser powered by solar panels. Depending on the speed and size of the asteroid, one to dozens of satellites can be used, which makes the anti-asteroid defense system quite flexible. So far, the development of powerful space lasers is in its infancy. The military has accumulated the greatest experience here, although so far powerful high-energy lasers have not been used as space weapons. For a long time it was believed that it was impossible to effectively change the trajectory of an asteroid using a laser beam. Yes, at first a powerful beam heats up the surface of the asteroid, resulting in a gas and dust plume that creates jet thrust. However, this plume should scatter the beam and reduce its effectiveness. However, laboratory tests at the University of Strathclyde have shown that the interference from the gas and dust plume is less than expected, and the laser is able to continue working for a long time. Small laser interceptors are much easier and faster to manufacture than one huge ship with a multi-megawatt laser. At the same time, the use of a fleet of satellites equipped with high-energy lasers is a more reliable solution. Even if one or more satellites fail, the rest will continue to work, and the size of the constellation can be quickly restored. Another equally important application of laser interceptors can be the cleaning of near-Earth orbit from debris, the amount of which is constantly growing. Today there is so much debris in orbit that for the foreseeable future we may encounter the Kessler effect, when the density of pollution in space becomes so high that collisions between debris exponentially increase the amount of debris and new collisions. As a result, this may close the way to space for mankind for many years. Today, despite the continuous monitoring of large debris, there is no technology to destroy them. Laser interceptors could take over this function.

Other interesting news:

▪ Xbox 360 HD DVD

▪ Smart fabric from Apple

▪ European networks 100 Gbps

▪ Batteries with solid Li-S electrolyte are 4 times better than Li-ion batteries

▪ The new filter will separate the oil from the water

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Labor protection. Selection of articles

▪ article Sand falls out of someone. Popular expression

▪ article Where did the statues on Easter Island come from? Detailed answer

▪ article Angelica officinalis. Legends, cultivation, methods of application

▪ article IR locator for the blind. Encyclopedia of radio electronics and electrical engineering

▪ article Cable lines up to 220 kV. Laying of cable lines in cable structures. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024