Signs #2475528

Digital Tank Level Indicator shows up to 97 discrete water levels in the tank, which can also be changed by adjusting pot VR1. Digital Tank Level Indicator is especially suited for apartments, hostels, hotels, etc. where many taps are connected to one tank. In such cases, if someone forgets to close the tap, this circuit would alert the operator well in time.
Digital Tank Level Indicator uses just a two-core cable to monitor various water levels and corresponding readings on 7- segment display. The circuit operation is based on timer IC3 & IC4 and decade counter cum seven-segment display IC1 & IC2.

About the Circuit :As shown in the circuit diagram IC1 & IC2 forms two- digit frequency counter. The clock pin1 and CE (Clock Enable) pin2 are used in such a way that the counter advances when pin1 is held high and pin2 undergoes a high-to-low transition.
IC4 is used as an astable multivibrator, which generates continuous 30Hz clock pulses .The output of IC4 at pin3 is connected to CE pin2 of IC1.
The other timer IC3 is used as a timing pulse generator. The different duration of high and low periods of the timing pulses are achieved because of the charging and discharging paths for the timing capacitor C2 differs.
During positive duration of timing pulse at pin1 of IC1, the frequency counter is allowed to count the number of negative going pulses which are continuously available at its pin2. This counting is displayed on DIS1 and DIS2. However, at the end of positive pulse, the frequency counter is latched. During the following 4 seconds low-level period, display will show the current count. At beginning of the next positive pulse, the frequency counter resets and starts counting afresh.

Thus, this digital meter shows reading for 4 seconds duration and then goes off for a variable period of 0.5 sec to 3 sec. By adjusting preset VR2, the low duration pulse period  (4sec) can be set. The low pulse duration should invariably greater than 3 sec. Here Red LED D4 gives the visual indication that the clock pulses are generated whereas glowing of Green LED D3 indicates the timing of pulse generation.
VR1 is a linear wire-wound pot, is fitted in such a way that minimum and maximum water levels can be achieved by the movement of pot shaft. Preset VR2 and VR3 are to increase the sensitivity of the frequency count.

Note on Output Result :When power is on, the first counter output represented on 7-segment display may be random number due to timing adjustments. Nevertheless, at the next counting it will show the correct results or the correct output level.

Microcontroller Based Water Level Indicator With Voice Alarm gives four level indication & Speaks in Hindi language, using IC AT89C2051. This article illustrates the construction and working of a Water level indicator. Such an indicator is used in tanks to indicate the level of liquids and alert us when the tank is full. So by this circuit we can monitor the various levels of the tank and can avoid spillage of water and also we can configure our supplies according to the various levels of tank. Such module or circuit can be installed in big buildings where manual monitor of tanks is difficult and its indicator can be placed at some centralized place.
This circuit works on the principle that water conducts electricity. A wire connected to VCC and four other wires are dipped in tank at different levels namely quarter, half, three-fourth, full and their output are taken on pins P1.0, P1.1, P1.2, P1.3 via a transistor BC547.Also the LED indication of water level ¼, 1/2, 3/4, and Full connecting the port output P1.4, P1.5, P1.6 &P1.7 these LED indicates water level position by glowing indicating LED. Initially when the tank is empty speaker speaks in Hindi language “Tanki Khali” &. As the tank starts filling up wire at different levels get some positive voltage, due to conducting nature of water. This voltage is then fed to their corresponding pins on controller. When level reaches to quarter level, LED displays the message 1/4. On further rise of level, 1/2 and 3/4 are displayed on LED. When tank gets full LED shows the message by indicating. When tank is full speaker speaks in Hindi language "Tanki Bhar gaye".

Mail Indicator With Warning is specially designed for people, who make several futile trips to their mailboxes before their mail finally arrives. The idea is typically based on a sensor placed in the mailbox and the sensing circuit using IC40106 (IC1).

Mail Indicator With Warning consists of an LDR i.e. Light Dependent Resistor. When the letter is dropped in the mailbox, light falling on LDR is interrupted; its resistance rises and triggers the sensing circuit. The circuit will generate a noticeable alarm tone and simultaneously begins to flash two visual indicators.

About the Circuit :The heart of the Mail Indicator With Warning is IC1, which consists of six Schmitt trigger inverter gates. The sensor assembly consists of an LDR and a light source. The light falling on LDR keeps the output at pin2 is at logic low level. Diodes D1, D2 remains conducting and so the red ‘NO’ mail indicator LED D5 remains lit, and piezoalarm tone oscillator remains deactivated.
However, the moment a letter or a packet is dropped in the mailbox, the red ‘NO’ mail steady indication ceases. In turn oscillator designed around one of the inverter using R2/C1 operating at a visually attractive frequency of about 2 Hz and the set of green LEDs D3 and D4 indicating the arrival of ‘MAIL’, begin to flash. Simultaneously as D2 ceases to conduct, two inverters whose inputs are pin5 and 9 and outputs are pin6 and 8 simultaneously, both of which are wired in parallel to provide current drive boost, begin to oscillate at about 2KHz.This frequency is set by capacitor C2 and resistor R5.

Calibration :The sensitivity of the circuit is set by VR1. Adjust VR1 such that the alarm tone just goes off in the normal ambient light conditions. Next try putting a letter/envelope and ensure that it does set off the alarm.

The name of the Liquid Level Indicator Without Alarm itself suggests its application. Liquid Level Indicator can be used for level control in hydro culture project. Also, it can be used for detecting the level of water in washing machine. The main feature of Liquid Level Indicators is that it shows each level in meaningful English letters. Liquid Level Indicator displays letter ‘E’ for Empty, ’L’ for Low, ’H’ for Half, ’A’ for Above Average and ‘F’ for Full Tank. The sensors for each level are immersed in tank. Their other ends are interconnected through four NOR gates, which uses IC1. The output is then given to IC2, which is BCD to seven- segment display driver IC. The level of fluid is indicated on 7- segment display.

About the Circuit :As shown in the circuit diagram, according to the level of liquid in tank, IC1 triggers each NOR gate. The output of each NOR gate in IC1 is applied to BCD input of IC2. When tank is low, the logic of four NOR gates in IC1 gives BCD logic as 1010. Their logics are applied to BCD inputs of IC2. Hence, IC2 drives 7- segment display according to the BCD Code present at inputs. For low level BCD logic is ‘1010’. For this logic, display will indicate ‘L’. As the level increases, BCD logic changes, and display will indicate accordingly. That is ‘H’ for half and ‘A’ for above average. You can see the code generation table or logic table.

Note that there is no display pattern like ‘E’ or ‘F’ available from IC2. Therefore, to obtain these pattern transistors T1 and T2 are used. These transistors blank out the unnecessary segments from 7- segment display. It can be seen that the letter ’E’ is generated by blanking ‘b’ and ‘c’ segments while it decodes digit ‘8’. Letter ‘F’ is obtained by blanking segment ‘b’ while it decodes letter ‘P’.

Note :Liquid Level Indicator should not be used with inflammable or highly reactive fluids.

Microcontroller 89C51 Based Temperature Indicator With LCD is used to indicate temperature on Celsius & Fahrenheit on 16x2 LCD Display. Fahrenheit scale digital thermometer is a temperature indicator which displays temperature in Fahrenheit scale. It is similar to Celsius scale digital thermometer, except a little modification in the microcontroller program. The temperature sensed in Celsius scale in the Celsius scale thermometer project is converted into the Fahrenheit scale temperature just by using the Celsius to Fahrenheit conversion formulae. This project also uses 8051 microcontroller (AT89C51). A digital thermometer can be easily made by interfacing a temperature sensor to the microcontroller AT89C51. The temperature sensor used in the project is LM35. The LM 35 IC generates a 10mV variation to its output voltage for every degree Celsius change in temperature. The Output of the temperature sensor is analog in nature so we need an analog to digital convertor for converting the analog input to its equivalent binary output. The ADC 0804 is the analog to digital convertor IC used in the project. 0804 is a single channel convertor which converts the analog input up to a range of 5V to an equivalent 8-bit binary output.

We are a trusted Manufacturer and Supplier of Sound Indicator in India. All of us know it is impossible to separate sound effect and light effect. But this simple circuit makes it possible to vary the effect from simple to complex. This circuit is a sort of running light whose rate of change depends on the frequency and intensity of the sound.

About the Circuit :

• The circuit is build around two counter ICs, IC1 and IC2 as shown in the circuit diagram. The sound signals generated are received by condenser microphone. These signals are amplified by pre-amplifier circuit designed around transistor T1. It should be noted that the amplified level must be high enough to overcome the switching threshold of the counter, while its frequency determines how often counter is clocked. After amplification, the signal is applied to IC1 via P1, which controls the sensitivity of the circuit.
• Since audio frequencies are too high for making a good visual effect, the signal frequency is scaled down by IC1 when S1 connects pin11 with pin15 of IC1, when the switch is in other position, pin2 is connected with pin15, the counter then divides by 1 and the effect assumes a completely different character that no longer resembles a running light.
• The actual running light is provided by IC2, a counter with integral 1 from 10 decoder, which is clocked by the Q0 output at pin3 of IC1 of the ten output of IC2 each of which is connected to an LED, there is always one ‘high’. The ten LED have a common bias resistor R5, an arrangement that is perfectly visible since only one LED lights at a time.
• The power supply must be able to provide a current up to 100mA/200mA.
• Frequency of sound indicated on LED display.

Microcontroller Based Automatic Car Parking Indicator System is a project including infrared transmitter and receiver in every lane and a LED & LCD display outside the car parking gate. Now days in many multiplex systems there is a severe problem for car parking systems. There are many lanes for car parking, so to park a car one has to look for the all lanes. Moreover there is a lot of men labor involved for this process for which there is lot of investment. So the need is to develop a system which indicates directly which parking slot is vacant in any lane. The project involves a system including infrared transmitter and receiver in every lane and a LED & LCD display outside the car parking gate. So the person entering parking area can view the LED display and can decide which lane to enter so as to park the car. Conventionally, car parking systems does not have any intelligent monitoring system. Parking lots are monitored by human beings. All vehicles enter into the parking and waste time for searching for parking slot. Sometimes it creates blockage. Condition become worse when there are multiple parking lanes and each lane have multiple parking slots. Use of automated system for car parking monitoring will reduce the human efforts. Display unit is installed on entrance of parking lot which will show LEDs for all Parking slot and for all parking lanes. Empty slot is indicated by the respective glowing LED.

Room Temperature Indicator is a very simple temperature monitor circuit used to guess the nature of temperature. The ten LEDs are used to indicate whether it is hot, cold, or lukewarm. Room Temperature Indicator uses a linear voltage display IC1, which drives a display of ten LEDs in a bar or dot mode. Diode D1 in reverse bias mode is used as a temperature sensor.

About the Circuit :

• The drive voltage for IC1 is derived from a potential divider consisting of a sensor R1 and preset P1. This combination is adjusted to set the required operating temperature, so that first LED D1 glows. As the temperature rises further, LEDs glows sequentially.
• IC1 is a linear voltage display IC consists of 11 comparators which gets sequentially triggered as the temperature rises. Accordingly, LEDs D1 to D10 glows. This is in dot mode. The display can be shown in bar mode also by connecting pin9 to pin3 by switching S2. But it should remembered that in dot mode, the total current will remain below 20mA, but in bar mode it may be 100mA when all LEDs light.

The use of few ICs makes it possible to control the big traffic in modern way in your city. Our Modern Traffic Light Signal includes four set of poles having Red, Yellow, Green and Side-Green lights at each pole. At a time, Green Signal for opposite poles P1-P3 and RED signal for other two opposite poles P2-P4 ON. When the Green signal goes off, Side-Green signal illuminates for side way traffic. As the Side-Green signal of P1-P3 goes off, GREEN signal of P2-P4 and RED signal of P1-P3 becomes ON.
The circuit is designed using two-shift register IC3 and IC4, which consists of each eight outputs. It controls hold on time for each signal. IC5, IC6, and IC7 are used as a buffer to isolate the output. IC1 is used as an astable multi vibrator to provide clock input to IC3 and IC4. IC2 which is a OR gate IC used to give data-in signal to IC3.

About the Circuit :As stated in introduction IC3 which is a shift register has eight outputs. As we require 16 outputs for controlling the four set of poles two ICs are used. IC1 is used to give clock signal to IC3 and IC4 at pin 1 and 9 respectively as shown in circuit diagram. At every clock, pulse generated by IC1 output goes on shifting. When power is ON, IC2 provides data-in signal to IC3 at pin7. IC3 starts shifting the output. The first three outputs are used for GREEN signal, the fourth output for YELLOW signal. The next three output for SIDE-GREEN signal and the last output for SIDE-YELLOW signal. As this is, arrange for opposite two poles P1-P3, at the same time all the eight outputs are used as a RED signal for other two opposite poles P2-P4. At the last output of IC3, IC4 receives data-in signal by connecting pin2 of IC3 to pin7 of IC4. Now IC4 starts shifting the output. Ninth to sixteenth outputs generated from IC4 are used same as above, but for other set of pole.
The clock pulses generated by IC1 are indicated by LED D49, whose frequency is set by preset P1. Whereas when IC2 gives the data-in signal to IC3, LED D52 glows.

Calibration :                           It should be noted that the clock signal and data-in signal are adjusted in proper way. When power is on at first clock pulse, IC3 gets the data-in signal, which is indicated by glowing of LED D52. But the output starts at second clock pulse. When second clock pulse goes of LED D52 must also be goes off, otherwise the circuit does not work properly. This is adjusted by preset P2.

LEDs color specification for four set of poles are as follows :

• POLE-1 : D37-Red, D34-Yellow, D35-Green, D36-Green Right
• POLE-2 : D33-Red, D38-Yellow, D39-Green, D40-Green Right
• POLE-3 : D45-Red, D42-Yellow, D43-Green, D44-Green Right
• POLE-4 : D41-Red, D46-Yellow, D47-Green, D48-Green Right

Power Supply :The circuit requires a DC power supply of 12V. The 12V AC output from 12-0-12V transformer gets rectified by diodes D53/D54. Capacitor C10 filters the rectified signal. This rectified output is given to input of IC8, which is a 12V regulator IC. The final regulated output is applied to the circuit.