Paper humidity indicators. Wet smartphone: how to immediately determine how much water ingress indicator

This small sensorhumidity (or water level - depending on the set sensitivity value)signals that a preset level has been exceeded by emitting a loud beep when the humidity sensor detects the amount of water.This circuit uses the LM1801 low power comparator - National Semiconductor.The reference voltage for the integrated circuit regulates the resistance R2.
When the voltage on pin 4 of LM1801 exceeds the specified threshold, an intermittent sound will be heard. The piezoelectric emitter consumes a current of no more than 24 mA.
The water sensor has a consumption of 10 microamps, so you can use a 9V battery for almost 1 year.

(* unfortunately, the diagram does not indicate R2 and there are no dimensions of the sensor itself, so if anyone decides to assemble this device, they will only rely on their own experience when setting up the device - comment from RCL)

Source - http://electroschematics.com/5742/water-sensor-alarm/

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Hello! What is the first thing they look at at the service center when you bring your iPhone there under warranty? That's right, on your device. And in the second? External damage (is it broken?) and has it been exposed to water, as this is an excellent reason to deny you warranty service. The latter will be discussed today.

Almost every device (iPhone is no exception) has a so-called liquid contact indicator. To exaggerate greatly, this is an ordinary piece of paper that changes its color (once and for all) when any liquid gets on it. Thanks to it, you can always figure out whether the device is “drowned” or, conversely, it has never been touched by water.

The article turned out to be long (of course, because absolutely all iPhone models starting with the “four” were considered), so... table of contents:

iPhone – “drowned” or not? Why know this and preparation

Why do you even need to know where the water sensor is located in the iPhone?

1. Before going to service center so as not to run there in vain. Since the “drowned” will be denied warranty service.
2. Before buying a used iPhone (). Although, as readers say in the comments, you can encounter various problems when buying a new one.
3. Just out of curiosity. For example, I was never interested in what kind of moisture sensor it is and where it is located on my iPhone. And when writing the article, I was quite interested in how he was doing there?

A few more important notes:

1. According to the specifications, the sensor is triggered only upon direct contact with water. Any evaporation, condensation and other phenomena should not affect it. In practice, I can only confirm this. Bath, bath, steam - nothing made him react on my iPhone.
2. The normal color of the indicator is white or silver, any deviation (reddish, slightly colored, barely red) means that there has been contact with the liquid.
3. You may need a magnifying glass and a flashlight to look closely.

Well, now let’s get down to business and look at the location of the moisture sensor in each iPhone model. We won’t touch the earliest “Apple” smartphones, let’s start with 4 and 4S - they are still quite common and can be found on sale.

Where is the moisture indicator on the iPhone 4 and 4S?

These are the only models of all those being considered today that have as many as two indicators! Apparently, to be sure whether liquid got in or not. They are located:

1. In the headphone jack.
2. In the charging connector.

Please note that the indicator in the headphone jack is built very cleverly and insidiously. Considering the fact that the iPhone 4 and 4S have a connector located at the top of the device, any conversation in the rain and any “stray” (but accurate!) drop of this rain can become grounds for voiding your device’s warranty.

And the indicator in the charging connector is also not a good idea. After all, a little moisture can easily get there, but this never means that the entire device has been bathed. In the following iPhone generations this moment has been thought through...

Location of the water ingress sensor in the iPhone 5 (S, C, SE)

Do you think that the situation with the rain in the previous paragraph is all the author’s idea? Then give another explanation for that:

1. Starting with the iPhone 5, the headphone jack was moved to the bottom of the device.
2. And at the same time, the liquid ingress sensor was removed from it.

I don't find any other logical explanation. Well, okay, they removed it and put it away. The main thing is that they left at least one and, apparently for the reliability of identifying “drowned people,” they moved it behind the SIM card tray - directly inside the case.

Now, to determine whether the device was immersed in liquid or not, you need to pull out the SIM card tray. And already behind it we see a white or red indicator.

Moisture indicator in iPhone 6, 6S and Plus versions - where to look for it?

Apple did not invent or invent anything, leaving the indicator of liquid penetration into the body in these models in exactly the same place as in the previous ones. The only thing is that for some reason the company changed the type of sensor itself. It was round, but now they have made some kind of short strip. This is what he looks like and his location in the picture.

I honestly tried to guess why this was done, but other than the fact that the design of the case was conducive to this, nothing came to mind. If you have ideas, write in the comments.

Does the iPhone 7 (Plus) have a liquid contact sensor and where is it located?

In the iPhone 7, Apple added water protection to the device according to the IP67 standard, but this in no way means that it is completely protected from moisture. Moreover, this still serves as grounds for refusing warranty service.

How does the company know that water has gotten inside the device? Yes, everything is the same, because the liquid indicator will turn red. It is located in the same place as previous models- behind the SIM card tray.

Is it true appearance it has changed again - now the band is twice as large as in the iPhone 6S. Again, it’s a mystery to me – why? Any ideas - I'm waiting in the comments.

Where is the liquid contact indicator located on the iPhone 8 (Plus)?

Since the iPhone 8 is actually the direct successor of the iPhone 7, its moisture indicator is located in exactly the same place. We take out the SIM card tray, if necessary, arm ourselves with a tool (flashlight or magnifying glass) and look.

Do we see the sensor painted red? Everything is bad - this iPhone 8, with a high degree of probability, is a “drowned man”.

Where is the moisture sensor located on the iPhone X, iPhone XS, iPhone XS Max and iPhone XR?

Apple made the anniversary iPhone X a truly new device - new design, new functions, new technologies and... the “old” moisture indicator.

Yes, yes, nothing new - the same SIM tray and behind it a white stripe, which turns red if liquid gets inside the device. Although, in this situation, no “novelty” is probably required - what’s the point of changing something that already performs its function perfectly?

Updated! For the iPhone XS, iPhone XS Max and iPhone XR, again, nothing has changed. The liquid ingress indicator was completely copied from the iPhone X - it is absolutely identical and located in the same place (see picture above).

As you can see, the location of the moisture sensor is in all more or less modern iPhone models the same. And, perhaps, this is the only right place. Which, on the one hand, saves from false alarms due to splashes and the slightest contact with water. On the other hand, it guarantees that if water gets inside iPhone cases- then the first thing it will do is pass through the moisture indicator and it will react to this by turning red.

P.S. As always, I look forward to your questions and answers in the comments - feel free to write!

I. ZABELIN, Moscow

Two devices are offered that allow you to remotely determine the presence of water at the location where the sensors are installed, signal this and control actuators, for example, pumps.

One of them provides automatic monitoring of the health of the line connecting the device to the sensor.

The diagram of the first version of the moisture indicator is shown in Fig. 1.

Its operation is based on the humidity dependence of the voltage at the output of the divider formed by resistor R8 and resistor-sensor R5. The latter is installed at the control point, its current-conducting surface is cleared of paint, therefore, with increasing humidity, the resistance of this resistor noticeably decreases. As a result, the voltage at the divider output decreases from 6 V with a dry sensor to 2...2.5 V with a wet one. When the wires going to the sensor are short-circuited, this voltage will become zero, and if there is a break, it will be equal to the supply voltage (12 V).

Analysis of the state of the humidity sensor and the connecting line going to it is carried out by three op-amp chips DA1. Resistive voltage dividers R1R2, R3R4, R6R7 set reference voltage values ​​at the inputs of the op-amp, with which the voltage value coming from the divider R8R5 is compared. LEDs HL1-HL3 (red) indicate situations that the operator should pay attention to. HL1 will be turned on when humidity increases, HL2 - when the line is broken, HL3 - when there is a short circuit between its wires. If everything is in order, the green HL4 LED is on.

At the output of the "Exclusive OR" element DD1.2, when the line is shorted or broken, a high logical level will be set, which will lead to the opening of transistor VT2 and the activation of relay K2, which gives the "Alarm" signal. At the output of element DD1.1, the same level will be set if there is moisture at the sensor. Transistor VT1 and relay K1 will generate a “Flooding” signal. Relay contacts K1.1 and K2.1 can be included in the dispatch alarm system or used to directly control pumps and other actuators.

Both relays are RES60 version RS4.569.435-02. The device is powered from any 12 V DC voltage source, designed for a load current of at least 100 mA.

In Fig. 2 shows a diagram of a device that allows you to control the presence of water between two levels - upper and lower, for example, in a tank, in a swimming pool or in another reservoir. The reference voltage (about 3.2 V) from the resistive divider R6R7 is supplied to the non-inverting input (pin 3) of the upper op-amp circuit of the DA1 chip and to the inverting input (pin 6) of its lower op-amp. Resistive voltage dividers R1R2 and R3R4 are connected to the inputs of these op-amps of opposite polarity, respectively, as well as sensors for the upper and lower permissible water levels in the tank. Pin voltage 2 and 5 DA1 in the absence of water, when the resistance of the sensors is very high, close to 6 V.

If the water in the tank has not yet reached the upper sensor, but has covered the lower one, the resistance of the latter decreases sharply. Pin voltage 2 (the inverting input of the first op-amp) of the DA1 microcircuit is higher than the standard one supplied to its non-inverting input (pin 3 of DA1) and the level at the output of this op-amp (pin 1 of DA1) is low. Since the resistance of the lower level sensor immersed in water is small, the voltage at the non-inverting input of the second op-amp (pin 5 DA1) is less than the standard one at its inverting input (pin 6 DA1), therefore the level at the output of this op-amp (pin 7 DA1) also low. Transistor VT2 is closed, relay winding K2 is de-energized. This situation is indicated by the green LED HL1 “Normal”.

When the water level is higher than the upper level or lower than the lower one, the states of the corresponding sensors, op-amps, transistors and relays change. The triggered relay connects its contacts in parallel with the HL1 LED to one of the red LEDs HL2 “Many” or HL3 “Little”. Since the forward voltage drop on a red LED is less than on a similar green device, when they are connected in parallel, the first one lights up and the second one goes out.

The second groups of relay contacts turn on the necessary devices (for example, a pump, etc.) or send signals to an operator located in another room.

The printed circuit board of the device is shown in Fig. 3.

Its dimensions are designed for installation in a standardized E12 housing of the STANDART series produced by BTR Electronic Systems. Two-wire lines They are laid to the sensors with a TRP-0.5 telephone wire. The actual sensors are the straight cut, uninsulated ends of the wires.

Power supply - network adapter at 14...20 V. A parametric voltage regulator for the supply voltage of the DA1 microcircuit is provided on the zener diode VD1. Relays K1, K2 (RES60) should be selected in a design that matches the supply voltage. For example, at a voltage of 14...16 V, relays of the RS4.569.435-02 design (winding resistance - 270 Ohms) are suitable, at 16...20 V - RS4.569.435-01 (800 Ohms), and for even higher voltages - RS4 .569.435-00 (1700 Ohm).

The available hardware redundancy (the LM324N chip contains four) allows you to assemble two identical devices on it, “doubling” the described circuit, and monitor the status of four sensors.
Editor - A. Dolgiy, graphics - A. Dolgiy
[email protected]

Humidity indicators are a card made of moisture-absorbing paper on which...

Provide control over the conditions of storage and transportation of goods, raw materials, materials. The humidity level is determined by the change in color of the corresponding circles. The humidity indicator retains its readings in a closed bag for up to 5 years.
...

Humidity indicators

Paper humidity indicators allow you to identify cases where permissible humidity levels are exceeded. They are usually placed in packages containing electronic components or products that are sensitive to moisture. Thus, upon receipt of the package with the goods, the customer can clearly verify that the supplier and the transport company have not violated the storage and delivery conditions. Conversely, if the packaging was damaged during loading or transportation, then most likely the humidity level inside it has also changed. The color of the indicator will tell you how much it has changed.

Multicolored circles

Humidity indicators are paper cards with circles on which a chemical reagent is applied. The card may have 3 or 6 circles, depending on the gradation of humidity levels, for example: “10%–20%–30%” or “10%–20%–30%–40%–50%–60%.” And if the humidity reaches one or another value, the corresponding circle changes color. Even if the humidity level later returned to the specified parameters, the indicator will no longer be able to return to its previous color.

The Sovtest ATE company uses a blue-yellow-green palette for its paper indicators, where blue corresponds to a humidity level of 10%, and rich yellow-green color – 60%.

Advantages of paper indicators

Disposable paper indicators are widely used by electronics companies to monitor the level of humidity inside a sealed package of components and obtain information about its damage.

The main advantages of paper indicators are:

• reliability of information (laws of chemistry apply)
• impossibility of falsification (the reagent changes color only once)
• affordable price
• miniature sizes (can be placed even in small packages)
• shelf life 5 years (in sealed vacuum packaging)

By the way, humidity indicators must be stored in tightly closed packaging. It should be opened immediately before using the indicator. That is, you need to quickly take it out and transfer it to another package - with electronic components.

There are many cases in life when it is necessary to determine the degree of humidity. In the country house and garden, at school and at home. For example, indoor plants. They will do well if watered in moderation. But how to determine this line? If you water regularly, how often? After all, the consumption of moisture by a plant and the drying out of the soil (loss through evaporation) is an unpredictable process.

How to determine the moment when a new portion of moisture is needed? Plant lovers will be helped in their activities by a simple device, an assistant device, and a humidity indicator.

Even a novice radio amateur can make it with his own hands.

This requires a little detail, skill and knowledge. By carefully following the description given, you can make an operating and useful device.

The diagram of the humidity indicator is shown in Fig. 3.30. As you can see, we need two KR1156EU5 microcircuits and a few more parts.

A careful examination of the circuit shows that it contains two nodes - an audio signal generator on the DA1 chip and a control node on the DA2 chip.

Let's take a closer look at the operation of the humidity indicator. In the diagram we see the contacts. These are two electrodes (on the printed circuit board), which are the moisture sensor. On what

Rice. 3.30. Electrical circuit of the humidity indicator

What is the principle behind the operation of such a sensor? The fact is that dry materials (for example, earth) conduct poorly electricity. But once they are moistened, their conductivity increases sharply. This is precisely the reason why you should never touch electrical appliances with wet hands!

In our device, an increase in conductivity between the sensor contacts will lead to a decrease in the potential of the comparator input (pin 5) of the DA2 chip. And as is known (see Chapter 1), in this case the output transistors of the microcircuit will no longer be constantly in the closed state and will begin to periodically open and close. After all, the microcircuit is turned on as a pulse generator (see Chapter 1) with a timing capacitor C2.

The output transistors act as a switch and periodically supply power to the DA1 chip. It also generates pulses that are sent to the BF1 piezo emitter. Capacitor C1 determines the frequency of sound pulses.

Thus, when the humidity sensor (contacts) is placed in a conductive environment (wet ground), the DA2 chip turns on and the sound generator on the DA1 chip starts working. With “beep-beep” sounds and blinking of the HL1 LED, the humidity indicator makes it clear that there is no need to water yet. Another indicator (HL2) “winks” at this time. And with dry contacts, it lights up constantly and signals the presence of power.

This seemingly simple device is equipped with three indicators: two visual and one audio. And each of them performs its own specific function.

What should you do if you are interested in this device and want to make it? The first thing you need is parts. They are selected according to the list given in table. 3.11. The parts must be installed on the printed circuit board. It is made according to the sketch shown in Fig. 3.31. Installation of elements on a printed circuit board must be done carefully and accurately, as shown in Fig. 3.32. Particular attention should be paid to polar elements such as microcircuits, electrolytic capacitors and LEDs.

This device has some design features.

Considering that the indicator is used in unfavorable conditions of high humidity, the sensor contacts oxidize and are susceptible to corrosion. To protect this

Rice. 3.31. PCB sketch for the indicator

Rice. 3.32. Arrangement of elements on the board

Pos. designation

Acceptable Substitution

Piezo bell ZP18

Capacitors

K10-17 0.022 µF

K50-35 10 uF 63 V

Microcircuits

Resistor C2-33 0.25 W 10%

C1-4, them, 5%

Battery |

Indicators

I With any letter

section of foil on the board, you will need to tin it. This coating will significantly extend the life of the device.

It should also be taken into account that the sound emitter - a piezo bell - must be soldered on the back side of the board (on the mounting side) onto the protruding contacts.

After assembly, you must carefully check the correct installation of the elements and the quality of the soldering. After all, one bad contact can require a lot of time to troubleshoot and ruin your mood.

A correctly assembled device does not need adjustment and should work immediately. When the power supply is connected, the HL2 LED should light up. Checking the humidity indicator for operation is very simple - just touch the sensor contacts with your fingers. After this, another LED (HL1) should blink and a sound signal should sound.

This completes the production of the humidity indicator. We insert the battery and begin checking the soil condition of indoor plants at school or at home.

Careful handling of the humidity indicator will help extend its service life. To do this, its contacts must be thoroughly wiped and kept dry. If the device is not used for some time, the battery must be removed. This is necessary to extend its operating time and to prevent leaked electrolyte from damaging the indicator board.