Automatic Room light Controller with Visitor Counter
Project Cost :
Available in: 3 Days
Project Code: 1101
You will get a CD with this project:
CD contains following things:
1) Project Report in pdf format and in doc (word) format 2) Circuit diagram 3) PCB layout
4) Microcontroller program in assembley language
5) Hex file of the microcontroller code
6) Datasheets of all the components / ICs used in the project
Main concept behind this project is known as "Visitor counter" which measures and displays the number of persons entering in any room like seminar hall, conference room. LCD display placed outside the room displays this value. And when number of persons inside the room is zero, power supply inside the room can be cut using a relay interface, thus relay does the operation of "Automatic room light controller". This project can be used as Bidirectional person counter as well.
Description in detail:
Following are the important modules in this project:
1. IR Transmitter: We have implemented the Person counter module using 2 transmitters and 2 receivers.
We have used Infra-Red transmitters. Reason behind choosing IR LED is, infrared beams are not visible to human eyes. Transmitters used are IR LEDs.
2. IR Receiver: We have used an IR sensor - Infrared receiver. It is an active low device, which means it gives low output when it receives the Infrared rays.
3. Microcontroller: This is the CPU (central processing unit) of our project. We have used 89s51 which is a microcontroller of 8051 family. The various functions of microcontroller are like
I. Visitor counter section - Reading the digital input from two infrared receivers and calculate the number of persons from them.
II. Display - Sending the count to LCD so that the person operating this project should read the number of persons inside the room.
III. Automatic Room Light controller section - Microcontroller turns on the Room Light when person count is greater than or equal to one. And turn off lights when count is zero. This is done by Relay. Since relay is used, you can connect an AC bulb or DC bulb as per your requirement.
4. LCD Display: We have used 16x2 alphanumeric Liquid Crystal Display (LCD) which means it can display alphabets along with numbers on 2 lines each containing 16 characters.
5. Relay: We have used 12 volt relay. A transistor is used to turn on relay through microcontroller.
6.Darlington pair: It is used to increase the current gain. Output of 555 IC is given to the Darlington circuit. And output of Darlington pair is given to IR led, thus it increases current through Infrared LEDs which helps in increasing the range.
How to give demo of this project:
There are 2 transmitters and 2 receivers placed infront of each other. Swap your fingers (not single finger) or any object (like mobile) in front of those sensors. Then microcontroller will increment or decrement the counter. Once the count is non-zero, the relay is turned on.
Enhancement added to this project: We can add LDR - Light Dependant Resistor in this project. Purpose of LDR: LDR will detect the sunlight in the room (or we can say detect daytime)
If there is enough sunlight in the room (which means it is a daytime) then the relay will not be turned on. In this mode it will work only as a Person counter to save the electricity and works as enery saver.
And if there insufficient light in the room then only the relay will be turned on so as to turn on the bulb.
Applications and Advantages:
1. This project can be used in various rooms like seminar hall, where the capacity of room is limited and should not be exceeded. Project will display the actual number of persons inside the room.
2. Can be used in class rooms, conference room, study rooms in colleges.
3. This project can also be used in our home because many times we come out of our bedroom and forgot to turn off the room light.
3. When there are nobody inside the room then lights are turned off, thus this project helps in energy conservation.
1. We can send this data to a remote location using mobile or internet.
2. Voice alarm system can be added to indicate that room is full & persons can’t enter inside.
Question: Why you have used Infrared sensors to count the no of persons? Answer: Advantage of using Infrared sensor is that IR rays are not visible to human eyes. Also IR rays are not affected by any other sources.
For example: If you use LDR as a sensor then it can be easily triggered by sunlight or any other sources of light.
Question: Which type of fan / lights can be controlled using this project? AC or DC ?
Answer: We have used Relay to turn on/off the fan or light. So we can use any type of fan / light.
We can either use AC fan or DC fan as well. Relay provides isolation from the microcontroller circuit.
Thus user can use fan operating on 12 volt (CPU fan) or a 230 volts AC fan.
Question : Suppose two people walk into the room in matching steps interval will it sense one intrusion?
i.e. if two person enter the room without any gap between them then will microcontroller will detect 2 person or only 1 person?
Answer : If there is no gap between two persons, then microcontroller will sense that only 1 person has entered into room.
There should be some time delay (at-least half seconds delay between 2 persons)
Question : Are you using any separate counter IC for counting the persons or microcontroller itself is configured as the counter?
Answer : We have not used any separate IC for the counting. Microcontroller does all the functions. It is central processing unit for the project. It takes input pulses from sensor, counts the person, activate/deactivates the relay.
Question : How the counting of people using transmitters & receivers works ?
Answer : We have used to 2 pairs of Transmitter and receiver. These should be placed on the door frame, in-front of each other.
If a person enters the room then first receiver will cut and then second receiver will cut. Then microcontroller will increment the count.
And if any person leaves the room then second receiver will cut and then first receiver will cut. Then Microcontroller will decrement the count.
Question : Concerning pets in the room, are they likely to trigger the system?
What are the ways of avoiding false triggering?
Answer : Yes, your Pets can trigger the sensors. To avoid this situation, sensors should be placed at the higher level from ground. You can keep them at 4 feet from ground.
But 1 more thing, if your pets jump 4 feet from ground then this will trigger the sensor :-) :D
Can we use RFID reader & RFID cards in this project along with the Infrared sensors ?
Is it possible that in entry operation, the RFID will count and in the exit operation, the infrared will count?
Answer : Yes, this is possible. We can implement this project using RFID reader.
Whenever person enters the room, he/she will show the RFID card to RFID sensor and the counter will count as one but the infrared entry will not be activated.
But when the person is leaving the room, the infrared exit operation will be activated and the counter will decrement by one and the lights will turn off if nobody is in the room.
The RFID sensor will be placed outside the room for the Entry and the infrared sensors will be placed at side of the door for the exit operation.
Meaning, if the person enters the room and he/she shows the rfid card to rfid sensor, the rfid will activate but it disregards the infrared entry operation.
But leaving the room, the infrared will do the task and the counter will decrement.
Question : If this project is used during daytime then lights will always turn on & off and this will lead to wastage of electricity. How to overcome this situation? Or can't this project be used during day time?
Answer : In some specific seminar hall, conference rooms and study rooms, sunlight can not reach in daytime as well. This is to give some presentations on projector or big screens. In these cases lights are turned on even in daytime.
In other cases, where sunlight is enough and lights are not required in day time, we can turn off the project so it will not function. And then we can turn on the project in evening time.
Question : I tried to replicate the circuit of the transmitter and receiver on a bread board using the given components. The output of both transmitters was adjusted to 38 KHz. But the IR receiver is not giving active low output. What can be the problem?
Answer : Use a potentiometer to adjust the frequency of transmitter circuit. Also check the connections of TSOP1738 IR receiver circuit, sometimes problem could be in receiver.
Question : In this project can we use any sensor other than TSOP1738? Any animal like dog may also enter the room & will get counted by the counter, this will lead to an error. Can u suggest any other sensors which will detect only human being or human body?
Answer : TSOP1738 IR sensor is the most suitable sensor for this project.
Question : I have prepared the circuit of 555 timer which is giving output of 38khz. Problem is that the Red LED connected to the IR receiver is always active (always turned on) and only blinks when I try to cut the infrared beam from the arrangement of IR transmitter and receiver which you sent me. What can be the problem?
Answer : I have reviewed circuit and have 2 suggestions. First one, Capacitor connected to Pin 5 of IC555 should be 103 pico Farad.
And the third terminal of potentiometer RV is left open. It should be connected to second terminal of variable restistor RV. Then set the resistance between pin 7 and 6 to 11.4 kohm. If the circuit is still not working properly then try varying the potentiometer, reduce the resistance. LED should turn off when Transmitter is facing towards Receiver.
Question :Can this model hypothetically sense whether a person is going in or out of a room?
Can the IR sensors detect obstructions only, not the direction?
Yes, IR sensors detect the direction. This project has 2 sensors. So when person goes in 1st sensor is cut and then 2nd sensor is cut.
Thus microcontroller increments the count. I have added image of how to install sensor on door on this webpage: (see at the end/bottom of page)
Question : Doubt concerning the placement of IR sensor in the door frame. In the website you have given a chart showing the placement of the circuit, in that picture the transmitter1 and receiver2 is on one side of the frame and vice versa. Why is it so? Do you have any specific reason? Can we place TX1 & TX2 on the same side?
Answer : You can place Tx1 & TX2 on same side but it will reduce the efficiency of the receiver as both IR receivers will receive the rays from both transmitters, so if the distance between 2 receivers on one side of door is less then chances are there that it will not identify that person is entering the room.
Do you have question or any feedback about this project?
Please email your questions to: info @ mtronixtech.com
How to place these sensors on door:
Below is the diagramatic representation on how the two sensors should be placed on the door frame