AVOIDING THE FLOODMany families today live in multi-storey buildings and use of household washing machines. Everyone who connects this machine (for electrical switchboards and sanitary communications), knows how important both of these operations. In particular, when defective connection drain pipe to the housing ganovim the pipes of communication may occur leakage of water which not only spoil the mood and the interior, but also bring tangible expenses payment of repairs to neighbors below. Even when quality of connection clamps, tightening the corrugations, and pipes drain hose of the washing machine, we recommend that from time to time to check for leaks and if necessary tighten.

In addition, leaks can occur and in other cases, for example, the top (due to marriage in the work of the builders), if the apartment is located on the top floor, or because of outdated and curry favor with “all terms” regular plumbing communications (pipes, pipes, drain openings of sinks, etc.). All these cases also threatened with flooding the neighbors living downstairs, with all the ensuing consequences.
To avoid such hassles, I recommend a simple device — alarm of leakage with a sensitivity adjustment over a wide range and audible indicator. When setting the maximum sensitivity, the instrument responds to even the high humidity around the sensor. Sound signaling device provides an intermittent and loud sound approximately 40 dB in the case of dangerous situations.
The device is assembled on the chip К561ТЛ1 (the circuit uses only one element). This multi-function chip is popular among radio Amateurs and has a number of advantages compared to other chips К561 series. In the chip К561ТЛ1 includes four of the same item, And (with inversion) with the transfer characteristics of Schmitt trigger. The transfer characteristic of each element has two threshold and release. The difference Uсраб and Uотп is the voltage hysteresis, which in this case is proportional to the voltage. Due to the high sensitivity of the chip elements К561ТЛ1 managed to create a site that responds to a slight change of the input voltage.
Between the entrance of the element DD1.1 and “+” power supply included a variable resistor for regulating the sensitivity of the device. At the top (the scheme) position of the R1 engine, the sensitivity of the node is minimal. As you can see — nothing difficult in it, and she could gather perhaps every student.
Fig. 1. A circuit diagram of beeper leaking
Fig. 1. A circuit diagram of beeper leaking
The second most important element in the scheme is the humidity sensor. It is structurally made of the sensor rotation motor, floppy disk (floppy disk) MS-5301, which are now anachronistic, but were once very popular with the Amateur radio operators, who were into independent Assembly of personal computers of type “Radio-86rk”, “spectrum” and others. The motor drive carefully disassembled and removed the speed sensor (photo 1).
The photograph clearly shows that the closed conductors of the track arranged in the shape of the maze, cut with a scalpel in one place. It is made for disconnection of the shorted sensor circuit. Electrical conductors are soldered neatly to the standard contacts (clearly visible in the figure) flexible wire MGTF-0,6. The device and sensor are connected to electrical wires up to three meters (the length has not been tested) — it may be a twisted pair of the same wire MGTF, phone wire or flexible electric wires. Directly to the sensor it is necessary to solder only a flexible wire MGTF (or similar) so as not to cause delamination of the tracks on the metal base of the sensor. And then this wire can be connected (e.g., through an electrical terminal block) wires with different flexibility and cross-sections. At the other end (of the enclosure) these wires go into connector B2B-XH-A or equivalent.
Before using a sensor with fine sandpaper and remove a small layer of varnish covering the conductive traces on its surface.
Until around the sensor is dry at the entrance of the element DD1.1 high voltage level. The output of the element (a conclusion of 3 DD1.1) is low level, and the alarm is off. With little humidity, and the effects on the sensor drops of water on the input element voltage decreases, by virtue of the transfer characteristic of the Schmitt trigger internal state of the jump is reversed, at pin 3 of the chip DD1.1 is high. The transistor VT1 (КТ605БМ) is opened and through the capsule NA1 current flows — the audible alarm will sound.
The disadvantage of the entire device is some sluggishness of turning off the alarm associated with the drying of the sensor. However, this is output upon detection of a leak and its location the alarm device to forcibly turn off the switch SB1.
If this is not done, the device will turn off the alarm and will automatically switch to standby only after the drying of the sensor.
Circuits of this type are low-power, and the output current of each element does not exceed a few mA. So the exit of the element DD1.1 is connected to the current amplifier transistor VT1. In the collector circuit of this transistor included audio cap with a built-in intermittent AF generator type KR1-4332-12, which can be purchased in stores, radios, simply put, for 20 rubles. The elements of the device are mounted in any suitable compact housing. In the author’s version used the case from a aquarium air compressor. The conductors of the power supply can be connected via connector x2 (for example, from a battery of the type 6F22 “Crown”) or put through the standard hole on the side of the device, as you can see in photo 2.
The device is in adjustment not needed and begins to work immediately after power-on. The sensor is placed on the floor in an inaccessible place under the pipes (where it is not visible) contact pad upwards, if necessary, fix the wire with tape to the floor. Before first turning on the engine of the variable resistor R1 is set in the middle position.
To verify that the device at a distance of 0.5 — 1 m from the sensor, spray the moisture from the tank for Ironing (or another container with a sprayer). That should be enough to “Wake up” alarm sound.
As a power source is applied industrial device PU-1M production plant “Severny press” (St.-Petersburg). The output voltage is 9 V or 6 V. For this purpose there is a corresponding switch on the power. Power supply with transformer isolated from AC mains. Maximum load current is 150 mA. In addition to the power source, you can use any (including non-stabilized) with an output voltage in the range of 7 — 12 V.
When connecting audio cap with integrated intermittent generator must observe polarity.
Chip К561ТЛ1 can be replaced К564ТЛ1, CD4093В. Variable resistor R1 — type SPO-1 or similar, preferably with a linear characteristic. Fixed resistors type MLT-0,25. Transistor VT1 — CT-605БМ, КТ603, КТ608, КТ801, КТ815, КТ972, 2SC1573, 2N4927 and similar. Sound capsule — any with a built-in generator, designed for direct voltage 5 — 15 V and current to 100 mA. For example, FХР-1212, FМQ-2015IN — in these cases the sound is not intermittent and monotonous. Oxide capacitor C1 smooths out the ripple voltage. The switch SV1 staff located in the housing of the compressor. You can use any other miniature toggle switch, for example MT-1.
Photo 1. The rotation sensor of the motor of the floppy disk MS-5301
Photo 1. The rotation sensor of the motor of the floppy disk MS-5301
Photo 2. Ready device to a power source
Photo 2. Ready device to a power source
Indicator led HL1 АЛ307БМ connected all the time — it signals about the health of the device being in readiness.
Is specified in the scheme apply any other led current to 20 mA, for example, ARL-5013URC-B.
Obviously, the considered sensor are not every Amateur radio operator, so it can be replaced with homemade, for example, the following structure. The connecting wires are soldered to two metal spokes. The spokes are arranged parallel to each other on the floor at a distance of 0.5 — 1 cm (near the expected leak) and fastened to the floor with an ordinary band-aid. The material of the floor either.
In addition, the design of a multivariate sensor. Of decisive importance in this device has high sensitivity chip to even a slight change in the resistance between the contacts X1.

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