Fish Tank Pump

Simple Aquarium Controller

August 29, 2019

The scheme of the controller for the aquarium provides control of water temperature and lighting control, according to a predetermined time schedule. The aquarium controller also provides for the manual control (on / off) of the filter and the water pump.

This is especially useful when cleaning the aquarium, you do not need to pull the filter cord out of the socket, but you can simply press a button on the controller.

Description of the aquarium controller

Aquarium controller built on a PIC16F677 microcontroller. Firmware, most likely, should be suitable for higher level microcontrollers from this group. The operation of the circuit was tested on the PIC16F690 microcontroller. Temperature measurement provides a digital temperature sensor DS18B20 with a resolution of 0.5 gr. Celsius

The countdown is organized using a DS1302 chip – a real-time controller. In the event of a power outage, capacitor C8 is connected to DS1302’s 8-pin (backup power output). Its capacity lasts more than 3 days in order to avoid a time reset.

All control is carried out by four buttons: "LIGHT" (S) "HEAT" (T) "water pump" (V) and "FILTER" (F). A short press will turn on / off the corresponding channel. You can switch between manual and automatic control mode. This only applies to lighting and heating. The on / off of the water pump and filter is carried out only in manual mode. Heating automatically keeps the desired set temperature of the water in the aquarium.

Simple Aquarium Controller

Lighting control: the first press turns on the light, the second turns it off, and a third switches the light control to automatic mode. To set the on / off time of the light, you must press the button (S) and hold it for more than 4 seconds.

First set the on time. Short presses of the button (S) switch from one digit of the indicator to another, the value of each can be changed with the buttons V () and F (-). Further, by long pressing the button (S), the value is saved and the transition to the off-time settings takes place. Here the order of settings is the same. Another long press takes you to the initial state.

The temperature setting is almost the same. A long press of the button (T) allows you to switch to the mode of setting the required water temperature in the aquarium. Change in increments of 0.5 gr. Celsius is carried out with the V () and F (-) buttons. After installation, long pressing of the button (T) switches the controller to the main mode.

Setting the real time value is carried out by simultaneously and long pressing of two buttons (S) and (T). Then everything is the same as when setting up lighting. All values ​​are stored in the EEPROM, and when the power is turned off there is no need to re-configure everything.

Indication of the status of each channel is graphical. Each channel is designated by its letter: “LIGHT” (S) “HEATING” (T) “water pump” (V) and “FILTER” (F). If the letter on the screen is capitalized, it means that the channel is on, if it is in capital, then it is turned off.

Even under each of the above listed channels, either the letter A (automatic mode – automatic) or the letter M (manual mode – manual) is entered. Also on the indicator displays the date, time and the actual water temperature in the aquarium.

Simple Aquarium Controller

For convenience, the power part of the controller is made separately and connected to the main board with a TP-wire with an RJ-45 connector. The transformer for the power supply will suit any with the output on the secondary winding – 9 V and a current of at least 400 mA.

Which timer is better – mechanical or electronic? These questions can be answered in the article.

There was a time when there were no timers and hours, too, but there was already an aquarist (with a certain amount of imagination, of course).
Then the clock appeared and the aquarist began to acquire the look that we now perceive.
Then a lot of watches appeared – mechanical, electromechanical, electronic, atomic and so on. Aquaria, too, has moved from small opaque vessels to large transparent vessels in tens of tons of water.
People are tired of running around these large and transparent water tanks and they came up with automation that was turned on / off at a certain time – this was done using timers.

Home aquarium also moved in the direction of automation and first place in it took a timer!

However, beginning aquarists, because of their little experience, are always puzzled with questions:
– How often do you need a timer in aquarium?
– How best to use it?
– Which timer is better to use electromechanical or completely electronic?

Let’s start with the banal and the simplest: – “How often do you need a timer in aquarist? How best to use it?

The timer itself will turn on or off a particular device.
For example, turn on the light in the aquarium in the morning and turn it off in the evening.
Turn on the air pump for supplying air or the solenoid valve for supplying CO2 (carbon dioxide) at the right time.

Imagine the situation with lighting – we need to work or study early in the morning, and it’s still dark outside, having turned on the lights in the aquarium abruptly, we can cause a “quiet” panic among aquarium inhabitants.
It is advisable to turn on the lamp in the aquarium when the daylight from the window fills the room and the fish wake up. And how can this be done in winter days when it is late and we left home for work / study long ago? Or let’s say in the evening we went to the cinema, or to the play, sat up at a party – who will turn off the light in the aquarium without our participation? We are going to the country, or on vacation, who will turn on and off the light in the aquarium?

Everyone knows that the aquarium is a natural environment and the light in it should correspond to the correct light day (8-12 hours of illumination). At the same time, it is necessary to avoid either the lamp is always on or off.
It is in such situations that the timer is irreplaceable. Its operation facilitates the maintenance of the aquarium, helps to sustain the duration of daylight hours without extra light hours.

Having several timers at once, we simplify the task even more.
The second timer will be responsible for the operation of the water pump. At the right time, turn it on and off. In some aquariums, with a certain number of fish and plants, aeration is required around the clock. Working without interruption, many water pumps quickly fail, having developed all their resources. The timer can be programmed so that during the day he can rest the water pump. For example – three hours a day, at different times, every 7 hours of work. Very comfortably. Option: the water pump rests from 12 am to 1 pm, then from 8 pm to 9 pm, then from 4 am to 5 am

Consider the following question: – "Which timer is better to use electromechanical or fully electronic?"

Both have a number of advantages and disadvantages

Electromechanical Timers differ from each other by the presence of a switch that allows the device included in it to work directly, bypassing the time settings of the timer itself.

Programming an electromechanical timer.

The presence of a switch on the timer makes it easier to use. When you need to turn on the light or water pump directly, you do not have to pull the plug out of the timer and plug it into a free outlet, just move the lever and the timer turns into a normal power source. This may be necessary in the case when the timer program at the moment turned off the light, and we needed to consider something with the lights on.
For example, guests came, and our aquarium in daytime rest mode, we just move the lever, admire the fish, while not knocking the settings of the timer itself.
The main thing then is not to forget to screw the regulator to its original position, otherwise the light in the aquarium will work around the clock.
The timer does not have such a switch, it loses much, because we have to pull the plug out of it to directly turn on the device that we need to use.

Electromechanical timers.

Almost all electrical timers are programmed in the same way. Each such timer has a round dial with a time scale and lever plates that directly set the on-off program.
Each such lever allows the timer to turn the device on and off in 5-10-15 minutes. (for each timer model, this interval is set by the manufacturer and is not adjustable). This disadvantage, since the fully electronic timer has the ability to on-off every minute.
By bending / snapping the lever-plate down, we turn on the period of time during which the electrical appliances must be in the on state. With this we set the operating time of our aquarium lamp or water pump.
The timer clock must be adjusted by turning the dial in the direction of the arrow until the triangular mark (or direct risk mark) indicates the current time. Turn the timer into an outlet. Turn on the plug of the device of your choice in the socket of the timer, make sure that the regulator is in the position of the timer itself.

The disadvantages of mechanical timers are as follows:
1. The specified program is constant for each day of the week;
2. In the event of a power outage on the network, the timer goes off for the length of time that there was no power;
3. Some models tick or emit a characteristic crunch, as in a mechanical or electromechanical alarm clock;
4. More often fail, the program disk ceases to rotate (the plastic gear mechanism is apparently wearing out)
5. Ladies with a gorgeous manicure and beautiful long nails, after a power failure in the network has occurred, screw the disc into the desired position without touching the levers that strive to catch the nail and knock down the entire previously exposed program

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Advantages of mechanical timers:
1. The budget in the acquisition;
2. Easy to operate;
3. Gives some tips if you have a complex biotope, or gentle fish.
It is clear that in the event of a power outage, all vital aquarium equipment stops working (light, filtering, aeration, heating) and electromechanical timer without electricity also does not work !
After all, while we are at work / school or at the dacha, how do we know if the power was turned off and for how long it was critical that there was no electricity? That is where the lack of such a timer helps – it gets off on that length of time that there was no electricity.
The disadvantage turns into an advantage.
We will always find out whether stopping our equipment was critical, especially filtering (but the filter should not be connected via a timer, as it should work around the clock).

Electronic Timers differ from each other mainly in the design of the external form and a couple of bells and whistles / functions. Some have the function of switching to summer-winter time, others respond to movement (turn on / off when approaching the device connected to this timer)

Electronic timers.

All electronic timers are equipped with a switch that allows the device included in it to work directly, bypassing the settings of the timer itself. (The principle of working with this switch is the same as that of the electrical timer described above).

Electronic timers have built-in rechargeable batteries that provide backup power to the clock chip and therefore the configured program does not get lost when the power is disconnected from the network. As soon as the power resumes, the timer runs according to a previously set program.

Electronic timers have built-in batteries that provide backup power to the clock chip and therefore they do not allow the configured program to stray when a power outage occurs. As soon as the power resumes, the timer runs according to a previously set program.

Disadvantages of electronic timers:
1. Internal batteries are not eternal, and sometime it will be time to fully develop them. If you are unable to purchase new ones and replace, the timer can be thrown away.
2. As mentioned in the description of the electromechanical timer, when the power is turned off, we will not be able to use the hint (as in the case of the electronic mechanical timer) and find out if the electric power has been turned off. After all, the timer does not go astray, and does not lag behind that interval of time, until there was a voltage in the network.

Advantages of electronic timers:
1. The program can be set for each day. For example, during working days, the devices will turn on and off according to our schedule of employment at work / school, and on weekends at another time. Or even every day at different times.
2. The program can be exhibited for several days. For example, only the first or second half of the week.
3. The program can be set to trigger every other day.
4. The program can be set only for one every day of the week.
5. Compared with the electromechanical timer, there are only buttons on the front panel, there are no lever plates, there is no gear mechanism, and there is no alarm clock ticking.

Any timers that are electromechanical, that electronic ones allow the equipment to be turned on / off during the day at any time set by the program.
If you do not have live plants in your home aquarium, but artificial ones are used, you can take daylight breaks. In the morning, the timer will turn on the light for 2-3 hours, and during the day while you are at work / school, turn off the lights before you arrive. Daylight from the window of the fish is enough. In order that the aquarium water does not bloom and algae do not breed in the absence of living plants, it is advisable to make the daylight hours in the aquarium for 6-8 hours. This is especially true in very sunny rooms.

Simple Aquarium Controller

Simple Aquarium Controller

Simple Aquarium Controller

Simple Aquarium Controller

The interior of the electronic timer – E-TE-7x24x3, 6kW-D.

Electronic timer TGE-4.

The interior of the TGE-4 is closer.

Maybe someone will need, and maybe someone will laugh – they say, and what is there to understand, and so everything is clear. However, the instruction found and placed in this message. There are some more instructions for other electronic timers – I will correct and place it further.

Timer electronic minute TGE-2.

Voltage 230-240 VAC current 50 Hz
Max. load 16 (2) A, 3600 W
Minimum settable time 1 minute
Operating temperature -10 ° С – 40 ° С
Accuracy /- 1 minute per month
NiMH 1.2V battery> 100 hours
One outlet works through a timer, and the second outlet has a “direct” connection to the 220V network.

Before connecting the timer to electrical appliances, carefully read the following instructions.
Do not connect the device if the load exceeds 16 amps. The plug of any device must be completely inserted into the socket of the timer. Before cleaning the timer, unplug it and wipe it with a dry cloth.
Do not immerse the timer in water or other liquid.
Heaters and similar devices must not be left unattended. The manufacturer does not recommend connecting such devices to timers.

1) MASTER CLEAR: Clear all data in memory, including the current time and all programs.
2) RANDOM: Set or cancel the function "random".
3) CLOCK: Set the current time with the buttons WEEK, HOUR, MIN. Select the 12 or 24 hour mode with the TIMER button. Turn on the summer time function with the ON / AUTO / OFF button,
4) TIMER: Set programs with WEEK, HOUR, M1N. Select the 12 or 24 hour mode with the CLOCK button.
5) ON / AUTO / OFF: Select timer operation modes.
6) WEEK: Set the week with the CLOCK or TIMER button.
7) HOUR: Set the hour with the CLOCK or TIMER button.
8) MIN: Set the minute with the CLOCK or TIMER button.
9) RST / RCL: Replacing programs or returning replaced programs.

1) 10 ON / OFF programs in 1 minute increments.
3) 12/24 hour mode selection.
4) Large LCD screen with seconds.
5) There is a summertime function.
6) The function "random" with a random shift of 10-31 minutes from 6.00 pm to 6:00 am.
7) There are the following 16 combinations of days or sequence of days:
MO (Mon)
TU (Tues)
WE (Wed)
TH (Th)
FR (Fri)
SA (Sat)
SU (sun)
MO, TU, WE, TH, FR, SA. SU (Mon-Sun)
MO, TU, WE, TN, FR (Mon-Fri)
SA, SU (Sun Sat)
MO, TU, WE, TN, FR, SA (Mon-Sat)
MO, WE, FR (Mon, Wed, Fri)
TU, TN, SA (Tues, Thu, Sat)
MO, TU, WE (Mon, Thu, Wed)
TH, FR, SA (thu, fri, sat)
MO, WE, FR, SU (Mon, Wed, Fri, Sat)

1) Plug the timer into a 230-240 V power outlet and turn on the power switch. Leave the timer for approximately 14 hours to charge the backup battery.
2) After charging, clear all current information by pressing the MASTER CLEAR button with a sharp object (pen, pencil).
3) The timer is now ready for operation.

1) Press the CLOCK button and hold, simultaneously press the WEEK button until the current day appears. Keep pressing HOUR or MIN until the current hour or current minute appears. When installing, you can hold the WEEK, HOUR or MIN buttons for a quick change of values.
2) Release both buttons. Week and time will be set.
3) To reset the wrong time, repeat the steps above.

TIP: When checking your programs, make sure that the parameters do not overlap, especially when using block selection. If the set parameters overlap, the timer is turned on or off according to the program time, not its number. Turning off the program takes precedence over turning on the program.
1) Press the TIMER button and release. LCD shows ON_1. Now you can configure the first inclusion.
2) Press the WEEK button to set the day or sequence of days. Set the time by pressing the HOUR and MIN buttons.
3) Press the TIMER button again to complete the first power on installation and proceed to the first power off installation. LCD shows OFF_1. Repeat step 2, perform the first shutdown setup.
4) Press the TIMER button again to complete the installation of the first shutdown and proceed to the installation of the 2nd switch on. Repeat steps 2 and 3 to program the remaining parameters. Press the TIMER button and hold for 2 seconds to go to a quick change of values.
5) When the settings are complete, press the CLOCK button.
The timer is ready to go.

EXAMPLE: The timer turns on every day at 5:15 pm and turns off at 10:30 pm.
1) Press the TIMER button once and release. LCD shows ON_1
2) Press the WEEK button until the LCD shows “MO, TU, WE, TH, FR, SA, SU”
3) Press the HOUR button until the LCD displays 5:00 PM or 5:00 PM
4) Press the MIN button until the LCD displays 5:15 PM, or 17:15
5) Press the TIMER button again and release. LCD shows OFF_1
6) Repeat steps above with. and d., LCD shows 10:30 PM, or 22:30

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Modes of operation can not be changed when installing the program.
1) The required mode of operation is selected from the three available modes by successively pressing the ON / AUTO / OFF button.
2) Programs can only be executed in AUTO mode. If AUTO is selected, the timer runs according to the program. In MANUAL ON or MANUAL OFF mode, all programs are ignored and the timer does not work. If you select MANUAL ON mode, the output power is always on. If you select MANUAL OFF mode, the output power is always off.
3) When the mode from MANUAL ON switches to AUTO, the timer will keep the MANUAL ON setting until the next setting of the timer parameters.

1) Press the RANDOM button. LCD shows R (RANDOM). The "RANDOM" feature is enabled.
2) When this function is enabled, the parameters are executed with a random shift of 10-31 minutes from 6:00 pm to 6:00 am.
3) Press the RANDOM button again to cancel this function. The "RANDOM" function cannot be installed when installing the program.
4) The RANDOM function can only be performed in AUTO mode from 6:00 pm to 6:00 am.

Press the CLOCK and TIMER buttons simultaneously to switch the time display between 12 and 24 hours.

1) Press the CLOCK and ON / AUTO / OFF buttons simultaneously. LCD shows S (Summertime). The clock moves 1 hour ahead.
2) To return to the winter time, press the two buttons again. The clock returns 1 hour ago. S disappears on the LCD.

The following instruction with the preservation of the semantics of writing the person who wrote it. I think someone will need it too.

The instruction on the timer socket Rev Ritter, Frankfurt.

Timer socket Rev Ritter.

Hold clock> 3 seconds – switch mode 24/12 hours,
the on / off button toggles the modes always on / soft / always off.
C.D. button – Clock Down mode, countdown to trigger.

How to setup:
1. First, with a ballpoint pen, press the reset button
2. Then we select the 24 or 12 hours mode for someone as convenient, by pressing the clock key for more than 3 seconds. When the 12 o’clock mode is on the left, AM or PM is lit (Before and Afternoon). Because I got used to 24 hours, then the 24 hour setting examples. The mode can be switched at any time.
3. Press the set key until the day of the week flashes at the top, use the V- and V keys to select today’s day of the week.
4. after that, briefly press the set key and set the clock as well with the V and v- keys, set again briefly and in a similar way minutes. Set again – the current date setting is complete.
5. Reset to idle mode from any window – short press the clock key.
6. You can hold V or V- while setting the time in order to quickly set, for example, 24 minutes.
7. Next, set the power on, for example light every day. With the V and V- keys you can scroll through the programs, there can be 20 of them in total. The display shows the first character – the program number, ON / OFF mode, then the response time.

In order for program No. 1 to turn on the lights at 9 am and turn off at 6 pm, you need to set 1 ON 09:00 | 1 OFF 18:00 I think the logic of the timer is clear.

The mode with the letter d is the countdown mode to trigger. You can program, for example, turn on the light after 30 minutes, or turn off, respectively, if the light is on.

8. Select V program No. 1 ON with the key V, press the SET key – the days of the week will flash at the top. We need to turn on the light every day, so without changing anything, press SET again and just like setting the current time, set up further hours-minutes, set 09:00.
9. Select V program number 1 OFF with the key, press the SET key and in the same way set the shutdown time, 18:00.
10. Setting is completed, we plug the timer into the socket, and the lamp plug into the timer.

Here is an example of stepped illumination on a half-tint made using two electronic timers.

The lamps are divided into front and rear, which lamps where I stood I do not remember, but I found the scheme of their work.

Another instruction is already on setting up a QUIGG timer.

Since I have live plants in an aquarium, one day there was a question of sensible lighting. As you know, shining longer than 12 hours is fraught with the fact that you have a problem with all sorts of algae. Most often green. And to reduce the "light day" or to illuminate, as God puts on his soul, is bad for plants.

Now I have a lighting of 1 watt per liter in the aquarium. This is quite a lot, and if you do not control the time by setting the timer socket, firstly, such lighting is really to the delight of green fouling on the windows, and secondly, the electric meter for a month reels a non-frail amount of money. And I constantly got “overexposure” – a lamp of 160 kilowatts was burning for 14 hours a day.

I turn on the light in the morning until midnight as I am a night owl, I work late, and the aquarium in the study is pleasing to the eye. Earn and forget to disable. Yes, and it is desirable to remember what time it was included today. You take a break from work, admire the aquarium, how everything is green and beautiful. And so I do not want to part with this beauty.

One day, I decided that pretty! It is necessary to systematize the lighting time, set a stable 10 hours and no more! Yeah, you have to look for the outlet timer on sale! As it turned out, there is no sale, and sellers do not even know what it is. And finally, good luck! Once I saw it myself on the window, just guessed that this is it, that very thing! He looks like this.

Timer mechanical outlet

It is programmed for 24 hours. That is, the whole daily cycle, which we need. As it turned out, even the "blonde" will deal with him without difficulty.

  1. The first step is a switch. At the timer, it is on the side. Before starting the programming, it should be switched to the “permanent on” mode.
  2. All the little blue levers lift up.
  3. Turn the programming disk in the arrow to the right until the label on it matches the current time.
  4. Now we start programming. Each blue lever is equal to 30 minutes. Omit them down in turn, crushing your finger. You need, say, to set the time from 10 am to 10 pm Here in this time interval all levers should be pressed down. Exactly at 10 the timer will turn on electrical appliances, and at 22 they will turn them off. This program will repeat the timer daily. Once you set the program, you can forget about the timer. Switch the side switch from the "permanent on" mode to the "clock" mode.

But actually all! The service life of this device is 7 years. It can be called differently, for example, mechanical time timer. I ran out of problems with the haphazard lighting of the aquarium! I forgot the last time I cleaned the glass from green fouling. The light is on for exactly 10 hours. The device is simple and trouble-free. Recomend for everybody!

First we need:
1. The device itself. I took what was "Raptor".
2. Soldering iron.
3. Rosin and tin.
4. Nippers.
5. The wire that goes to the light in the cover.

Open the lid of the device. It is fastened there on the snap, and bite off the heating element with nippers. We will not need it. Do not throw out. It is useful for other cases. Let lie down while with other glands in the locker.

We push the wire through the holes in the bottom cover and solder it on the board instead of the disconnected wires.

We put the cover in place for safety and and everything. Can be used.

Now, at the appointed hour, we turn on the device with the help of a button on the case and provide you with 9 hours of lighting.
What is good and what is bad:
1. Cheap and affordable.
2. It is convenient if in your city it is problematic to find a factory timer.
3. The light turns on and off at the same time. Example: turn on at 10.00 and it turns off at 19.00.
4. Inclusion is made only once. Then you can simply forget about the device and its inclusion. It turns itself on and off at the same time.
5. It is inconvenient that the duration of illumination cannot be adjusted.
6. It is inconvenient that you can not take breaks in the lighting.
7. If you turned off the light in the house or you pulled the device out of the socket, you will have to put it back in the morning.
8. But the big plus is that anyone who does not have any knowledge about electricity and timers can collect it.
By the way, if you are not able to solder or not a soldering iron, you can cut the wires from the heating element at a greater distance and you just have to fasten them to the wires from the lighting and isolate them.
I think someone will come in handy.
Good luck!

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1.8. Simple aquarium timer

Aquarium timer, operating in a cyclic generation mode, today is not a news for radio amateurs. Industry (including foreign) beats all records for the production of electronic and electromechanical timers, programmed to time out at certain days and hours of the week (and month). The competition in the production of timers for domestic use has grown several times over a couple of years. However, for the amateur radio practitioner, it is still relevant today to create your own schemes, instead of those offered by the industry.

One of the schemes for this purpose, which embodied the simplest circuit design, is presented in Fig. 1.10.

Features of the device – in semi-automatic mode. At dawn (switching on the lighting in the room where the photo sensors are installed) the electronic device emits a short beep and switches on the low-current electromagnetic relay K2. The executive contacts of the relay K2, in turn, turn on the aquarium lighting lamp together with the water pump-pump (not shown in the diagram). The illumination lamp and the water pump remain on for almost 4 hours (depending on the ratings of the R5C2 elements). At the end of the time delay, the illumination lamp and the water pump turn off. With the new dawn (the new light is turned on in the room after a period of dimming) the cycle of the device is repeated – this happens every day.

At the heart of the device is a timer on the popular chip KR1006VI1. It is assembled according to the classical scheme in the mode of auto-generation of pulses of long duration. At the output of the timer, the electromagnetic relay K2 is turned on, with its contacts K2.1 it controls the supply of voltage to the aquarium water pump and the lighting lamp. The lamp can be either fluorescent (with the appropriate control circuit) or incandescent lamp with a power of up to 15 watts. Higher power is not desirable due to the possibility of overheating and reflow of the upper cover of the aquarium in which the lighting lamp is installed. water pump – any industrial for aquariums.

The control unit introduced the control unit of the KR1006V1 chip itself, depending on the ambient lighting. This is done so that the timer and, accordingly, the aquarium lighting lamp and the water pump are turned on only in the daytime, and at night they are not active. This photosensitive node is assembled on the same type of transistors VT1, VT2, loaded on the electromagnetic relay K1. The switching contacts of the relay K1.1 energize (or disconnect from the power) the chip DA1. In low light of the same type photoresistors СФ3-1 (connected in parallel and designated by a single designation on the PR1 circuit), the transistors VT1, VT2 are closed, respectively, the K1 relay is de-energized, the K1.1 contacts with numbers 3 and 5 (according to the diagram in Fig. 1.10) are open and the oscillator assembled on the DA1 chip does not receive voltage. Accordingly, contacts K2.1 are open and the aquarium lighting lamp and the air pump are de-energized.

Variable resistor R1 is introduced into the circuit for easy adjustment of the switching threshold of the transistor cascade VT1, VT2. Resistor R1 determines the sensitivity of this node to the luminous flux.

If the photoresistors have enough light, for example, during the day, the resistance of the photoresistors PR1 is low, the transistors VT1, VT2 are open, the relay K1 is turned on, the supply voltage is applied to the DA1 chip, the indicator LED HL2 (similar to the electrical characteristics of HL1) is lit. On the node sound indication powered. Chip DA1, included in the countdown mode time delay in accordance with the nominal elements of the timing circuit R5C2, starts counting the time. Relay K2 is on, the aquarium lighting lamp and the water pump are on.

At the end of the time delay set by the R5C2 element ratings (approximately 240 minutes), the high voltage level appears at pin 3 of DA1, the relay releases and the K2.1 contacts open, the illumination lamp goes out, the water pump turns off.

Now the next switching on will occur after the K1.1 contacts open (this will happen in low light, for example, in the evening and at night), and then close again with the onset of a new day or switching on the main light in the room where the PR1 photosensors are installed.

The audio node is connected directly in parallel to the power contacts of the device, the power of which it is designed to control, in this case parallel to the power supply of the DA1 chip.

At the heart of this electronic node popular chip K561LA7. Thanks to the use of one of its logical elements, as well as the use of a cap with built-in audio frequency generator (AF) HA1, it is not necessary to introduce any pulse generators or amplifiers to them in the circuit. The same node is also easy to assemble on logical elements of other CMOS microcircuits (for example, K561LE5, K561TL1), but the simplest circuit solution is shown in Fig. 1.10.

The short-term sound signaling circuit is based on a single logic element DD1.1 of the K561LA7 chip, which is included as an inverter. When power is applied to the input of the element (pins 1 and 2 of DD1.1), there is a low voltage level until the oxide capacitor C1 is charged through the limiting resistor R2. While this did not happen, there is a high voltage level at the output of the element (pin 3 of the element DD1.1). It enters through the current limiting resistor R6 to the base of the transistor VT3, operating in the current amplifier mode. Transistor VT3 is open, the resistance of its transition to the collector-emitter is close to zero and a voltage is applied to the piezoelectric capsule with the built-in audio frequency generator HA1.

When the constant voltage on the piezoelectric capsule with the built-in generator HA1 is almost equal to the supply voltage of the device, the capsule switches to the mode of generation of sound frequency oscillations.

As the capacitor C1 is charged through the resistor R2 and the internal node of the element DD1.1, the output state of the chip changes. When the voltage on the capacitor plates C1 reaches the switching level of the chip, it switches and the high voltage level at the output DD1.1 changes to low. Transistor VT1 closes. The constant voltage on the piezoelectric capsule with the built-in HA1 generator will be almost zero, and the capsule will go into standby mode.

With the values ​​of the elements R2 and C1 indicated on the diagram, the delay of sound switching off will be about 3 seconds. It can be increased, respectively, by increasing the capacitance of the capacitor C1. As a capacitor C1, it is better to use an oxide type K50-29, K50-35 and similar with a small leakage current. In the opposite direction, the duration of the time interval can be easily reduced by reducing the resistance of the resistor R2. If instead a variable resistor with a linear characteristic is installed, a device with adjustable delay will be obtained.

The function of this electronic unit can be reversed – that is, the HA1 piezoelectric capsule is silent for the first 3 seconds after being applied to the power supply device, and then it works the rest of the time. To do this, the oxide capacitor C1 and the time-dependent resistor R1 should be swapped (with respect to the polarity of the inclusion of the oxide capacitor – positive lining to the “plus” power). In this case, the middle point of their connection to pins 1 and 2 of the element DD1.1 is preserved. In this embodiment, the device without special changes can be used for a sound alarm open (over-measure) of the refrigerator door. In addition, the options for the application of this simple and reliable device are infinitely many and they are limited only by the imagination of the radio amateur.

From the book The Phenomenon of Science [Cybernetic Approach to Evolution] by Turchin Valentin Fedorovich

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