IR sensor (Line sensor)

Nowadays, in electronic market provides variety of IR sensor. Infrared (IR) sensors have become indispensable tools for several industries. However, not all frequencies of light within the infrared spectrum behave the same. There are a number of methods which can be used to build a line following robot. In general there are three different types of line followers which are single light, two lights, and three lights sensor model. On the other hands, besides using a complete sensor which it can easily find in the market, an infrared LED transmitter and receiver can be used to detect the line.

The reason of selecting this type of IR sensor is because it has good range which is fulfil the requirement for robots. It is very low cost and can be constructed on general purpose PCB. Besides that, it is very small in size which is best for robots. For obtain a good result, the number of transmitter and receiver can be increase. Thus, it has good immunity to ambient light and waves are invisible to eyes.

IR LED is used as a source of infrared rays. It comes in two packages 3mm and 5mm. 3 mm is better as it is require less space. IR sensor is nothing but a diode which is sensitive for infrared radiation. This infrared transmitter and receiver were known as IR Tx-Rx pair.

Pictures below shows the results after done with designing the PCB line, etching, components placement and soldering procedures.

Referring to the picture below, the input for the line sensor circuit is 5volts max. There are 3 pin for voltage output which are Vout 1(V1), Vout 2 (V2) and Vout 3 (V3). These output voltage pins are important to the system because every each of output pin will produce a different output voltage value which is directly connecting to the IC.

When IR sensor detects line, the voltage output is high but when it did not detect any line the output voltage is low. During troubleshooting the circuit, the result when detecting line is 1.59 volts and 0.14 volts is when it not detecting any line. On the other hands, each of voltage output pins control left and right motors.

Tip 120 as power transistor

A transistor is a semiconductor which is a fundamental component in almost all electronic devices. Transistors have many uses including switching, voltage or current regulation and amplification. Transistor controls a large electric output signal with changes to a small input signal. Since a large amount of current can be controlled by a small amount of current, a transistor acts as an amplifier. Transistor also acts as switch which can open and close many times per second.

The TIP120 also known as Darlington transistor. It was designed as a medium power switching transistor and can be used to switch a motor on and off. This type of transistor can use a small current to switch and amplify a much larger current to the motor or other load such as buzzer. The controlling pin on the transistor or base is sensitive to too much current, so the circuit required a 1k Ω or 2.2kΩ resistor coming from the output pin into TIP120. This transistor coupled with a motor power supply and will allow the circuit to run a DC motor and empower the circuit to activate many other devices. Therefore, for this project i used a TIP120 because it can pass more current especially if i add a heat sink on the transistor and handle larger load.

Troubleshooting the PCB line

After done with etching procedure, a PCB line should be check by using a multi-meter. This is important to ensure each component that will be install on the circuit board able receive a voltage and current and operate perfectly. Basically before soaking the copper board into the hydrochloric acid, the printed PCB line sometimes are not connected or dotted line. This problem can be fixing by drawing back those dotted line with a black marker pen and then continue soak the copper board into the acid.

Below picture shown the dotted line on the copper board

Making a connection troubleshooting using multi-meter.

Thus, the complete etching board will be drill to make a hole for electronic component placement.

Etch a single sided PCB

Etching is a printmaking process and where the excess copper is removed to leave the individual tracks on the circuit board. A muriatic or hydrochloric acid is important because it is used to remove the cooper layout on the circuit board.

\

Etch a single sided PCB

Etching is a printmaking process and where the excess copper is removed to leave the individual tracks on the circuit board. A muriatic or hydrochloric acid is important because it is used to remove the cooper layout on the circuit board.

The copper board can be cut into a necessary size needed and then clean it using a paper towel from any dust. Make sure our hands clean from any oil before touching the circuit board. Then place the pcb layout on a copper board and stick it using a masking tape.

Thus, get ready with a clothes iron and set the iron on the hottest setting to allow the iron get hot. Before start ironing the circuit board, use a thick clothes such as kain pelekat to sandwiching the copper board.

Firmly press the iron onto the back of the PCB layout for about 20 seconds and repeat the same method for more than 5 minutes. Without moving the iron, press board very hard for 1 minute to provide perfect heat to the circuit board. Then slowly move the iron around the copper board with a lot of pressure. After done with these methods, make sure the circuit board fully cool before removing the PCB layout from the copper board. 

Pour some hydrochloric acid on a plastic container and soak in the copper board into the acid. Wait for 4 minutes and shake the container slowly to remove the copper layout from the board.  The copper layout can be easily separate from the board by this method. Repeat the same method for 3 or 4 times to get a fully circuit board.

Separates the circuit board from the acid and leave it for 2 minutes. Wash the circuit board using clean water and brush the copper layout side using a sand paper. Repeat the same method until the copper layout completely removed.

Printed circuit board layout

PCB (Printed circuit board)

Printed circuit board is primarily an insulating material used as base, into which conductive strips are printed. The base material is generally fibreglass, and the conductive connections are generally copper and are made through an etching process.  The main PCB board is called the motherboard; the smaller attachment PCB boards are called daughter boards or daughter cards.

PCB board design defines the electrical pathways between components. It is derived from a schematic representation of the circuit. When it is derived, or imported from a schematic design, it translates the schematic symbols and libraries into physical components and connections

PCB layout

The PCB layout is a mirrored positive one- black on white. The PCB layout is printed 1:1 on paper by using a laser printer or copier machine. The laser printer or copier toner will not run out when it gets wet or oily. Therefore by using a laser printer the output will be fine and form in high quality of printing. It might be possible that the toner texture on the layout prints from the laser printer is not dense enough and passes too much light. However, results might be improved by setting the toner density.

OBJECTIVES

Gas leakage detector systems carry a positive objective that can be accomplished and might affect the world. The objectives consist of:

i.                     To upgrade and improve the existing system and device to detect any presence of flammable gas in         all industry or home.

ii.                     To reduce potential hazardous and prevent any major damage and accident in our country.

iii.                     To make sure all the data collected by all type of sensor involved continuously and it will be processed without any failure.

iv.                     To enhance a better function of the system in the future.

v.                     To expand the radius of detecting gas comparing with the existing system.

BENEFITS / CONTRIBUTIONS

The characteristic of liquefied petroleum gas (LPG) is flammable. By using the gas leakage detector, a presence gas such as butane or propane can be detected. It is part of the project purpose. Otherwise, this project able to:

i.         Reduce and avoid any possible incident especially explosion.

ii.       Avoid any major damage to the buildings.

iii.      To prevent serious injuries and breathing difficulties among the factory employees.

iv.   Reduce the global warming

METHODOLOGY

            A block diagram can be produce after done with a literature review on the principle operation, a technology and program involve, sensors involve and other. The gas leakage detector sensor requires more than one sensor such as MG5 gas sensor, LDR sensor, IR distance sensor and line sensor. Two small DC motor are needed to move the device from one location to another location. A gas leakage detector sensor also completed with alarm and buzzer system.

Block diagram

Figure 1.3: Block diagram for gas leakage detector system

Referring to the figure above, a MQ5 gas sensor is used to detect any presence of liquefied petroleum (LPG). When it detects any leakage of liquefied petroleum gas (LPG), a data will be send to the microcontroller which is A Tmega 328. The microcontroller will process the received data and automatically turn the siren or alarm on. A line sensor is optically detecting the specific line placed on the floor and move only on the specific line. A data received from the line sensor will be send to the microcontroller and run the DC motor (L293D). Furthermore, a light dependent resistor sensor or known as LDR sensor is used to detect the light surrounding the device. A data from this sensor will be read by the microcontroller and turn the lamp on. This will happen when the device moves into a dark places where no light on that area but it will automatically turn the lamp off when there is a light detect by the LDR sensor. The function of infrared distance sensor (IR distance sensor) is to detect any presence object against it. When it faces an external object or humans, it will send the data to be process by the microcontroller and turn on the buzzer to notify the user and organic life against it.

Table 1.4: Input, process and output of the block diagram

INPUT

1. .      Push button start and stop – Use to start and stop all the operation of gas leakage detector system.
2. .      MQ5 gas sensor – An electronic device use to detect any presence of propane or butane gas.
3. .      Line sensor – Is a sensor which only detect a black line on the floor.
4. .      LDR sensor – This sensor will be used to detect the light or dark area.
5.     IR distance sensor – It can detect any existing obstacle against it

         

          PROCESS

1.      ATmega 328 – Can store all the data written by the user and control all the system for gas   leakage detector system.

OUTPUT

1.      Alarm – Able to produce a high volume of sound and use to notify the user if any gas detected.

2.      DC motor – A low voltage motor use to move the device.

3.      Lamp or LED – Provide a indicator light when operates in a dark area.

4.      Buzzer – Notify the user if any obstacle block the device.