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Tuesday, May 25, 2010
electronics
LINE FOLLOWER ROBOT
TABLE OF CONTENT:
Introduction.
Overall task available.
Circuit diagram of the line follower robot.
Primary connection and testing using breadboard (prototyping).
PCB design (schematics and PCB layout).
Line tracking navigation of the LFR.
Diagram of the sensor position.
Motor type.
Steering method.
Chassis construction.
Final coupling and testing.
Conclusion.
INTRODUCTION
This is a simple mobile line follower robot (LFR) which is designed to follow black track (navigate through black track). The method or mode in which this robot navigates through the black track varies in speed depending on the complexity of the design. If the designer (engineer) decides to build a more complex circuit to control the robot either by using microcontroller and other programmable base component, then it will be able to control the speed of the robot while navigating through the black track but if a simple circuit (non-complex circuit) is used to build the robot then it will only navigates through the track with normal motor speed and hence no speed control and vise versa. This proposed line follower robot uses two sensors (left and right sensors) to differentiate between white and black surfaces in other to be able to navigate through the black surface. If the left sensor receive less light intensity, the robot will turn right (this means that the right sensor received more light intensity) but if the left sensor receive more light intensity, the robot will turn left (this means that the right sensor received less light intensity) and vise versa. The basic principal of the line follower robot actually almost the same as the light follower robot, but instead of tracking the light the LFR sensor is used to track the line, therefore by differentiating the line colour and it surrounding (white over black or vise verse) any light sensitive sensor could be used to navigate the mobile robot to follow this track. However the LFR is one of the most popular robot build by the robotics. What makes this LFR so popular?, this may be due to its simplicity and yet it could be used as the teaching tools of how we could implement the industrial standard control system such as the PID (Proportional Integral Deferential) control system on this robot. The successful implementation of this kind of line follower robot depends on the kind of engineers involved and how active their design and assembling of circuit component, testing process as well as troubleshooting processes.
OVERALL TASK AVAILABLE
Get specification.
Study and understand specification (analysis).
Design the robot circuit.
Bill of material (Bom), (materials required).
Assemble component (construct using breadboard).
Level test (verify if work according to specification).
Design PCB (printed circuit board).
Etching and drilling process.
Soldering of component onto circuit board.
Testing (initial testing)/ troubleshooting.
Design car and chassis.
Implement both designs.
Final testing and confirmation.
Finish robot (now working).
CIRCUIT DIAGRAM OF THE LINE FOLLOWER ROBOT
Figure1.
The 2N3904 NPN Bipolar Junction Transistor (BJT) is constructs to operate as the current gainer amplifier; this means we run the 2N3904 transistor in its linear region. The advantages of using the transistor in its linear region is; the transistor collector current passed through the DC motor, which vary according to the base current which is controlled by the LDR (Light Dependent Transistor) and 10 K trimmer potentiometer (trim pot). The trim pot is use to adjust the DC motor speed, while the 1N4148 diode is use to protect the transistor against the EMF (Electromotive Force) generated by the DC motor inductor when its switch off. The key of using this circuit successfully depends on the DC motor choice. Therefore the current through the DC motor will vary according to the light intensity received by the LDR.
PRIMARY CONNECTION AND TESTING USING BREADBOARD
The primary stage of the project where component need to be assemble using breadboard to test if the circuit designed above could actually be use to build the line follower robot (LFR) and moreover to verify if its work according to the specification given.
Figure2.
The primary connection was done as shown in the picture above and I supply 4.5 volt to the circuit after putting the motor in place and all other component connected therewith. I observe that it was working according to specification given and I proceed to PCB design immediately with the proposed circuit shown in figure1.
PCB DESIGN
Schematics diagram
Figure3.
The schematic diagram is as shown above, basically I use Dip trace to design the PCB and it was very challenging because some component were not found in its library so I choose any other components that has relative pin configuration and then add pattern to it from pattern.libs and change their values accordingly. However I converted the schematics to PCB but since Dip trace is not like Pcb wizard which has the capability to arrange the component in a unique way, so I arrange it manually and later run auto routing which make my pcb to look difference as compare to people that use PCB wizard.
Bottom view of PCB
Figure 4
The picture in figure 4 above is the bottom view of the PCB. This will be printed on board for etching which we need to used the etching chemical dissolve it in boiled water and put the board inside then shake it continuously until the outline peals off. The LFR car and chassis construction in this diagram is very simple as I just use a hardcore thick plastic measuring length 11.5cm and width 7.3cm for the main body construction and use caster (the third wheel) by using this easy to handle construction material, it was easy for me to build this line follower robot car and chassis, the finally coupling will seen in the other part of the picture below.
I use super glue to hold the 3 x AA (4.5 volt) battery holder and the micro DC motor, the DC motor also is reinforced with the plastic cable’s ties. The electronics component is soldered on the 5.5 x 3.5cm prototype PCB and I just use the mini-board to hold the LDR and LED together as shown on the picture below.
The picture on the right shows the side view of the car with one wheel and the mini board used to hold the sensors together on well placed position to the front of the car whereas left picture just shows the top view where you can see the battery holder and the two wheels in their fixed position.
FINAL COUPLING AND TESTING
This portion note down how the robot works and after the coupling we had some problem with our circuit but since the circuit was working initially we were a bit uncertain about where the fault could be because the sensors that were working stop working and motors is either one turn or both not turning and if both are turning it will be at high speed while the other at low speed, then we try to fixed motor problem and sensor problem. At this point we still couldn’t make it but later we discover that the transistor seem to be the entire problem in the circuit so we try changing the transistor and after changing the transistor with series of other circuit troubleshooting, the sensors and the two motor were working properly and I believe the transistor had some defect. Now our robot is ready to navigate through the black line.
The picture above show how the line follower robot navigates through the black surface. This actually means that we meet the requirement as stated in the specification, the robot simply follow the black line track.
CONCLUSSION
The project to design a line follower robot, though a simple project is actually very challenging as we really need to work hard in testing our circuit and have better troubleshooting technique that will help if any peripheral fell to work. However, for higher speed line follower robot with more complex track, we need to use the microcontroller, although it’s possible to use discrete electronics components but it required more complex circuit than the microcontroller based and transistor based which their solution become more simple and cheap to be used. For the transistor based circuit use in this line follower robot we iteratively check and troubleshoot the circuit component and test point although somewhat difficult to get it at first instance that we set on. After all the effort our project was successful and meet the requirement although it might not really meet the industrial standard but I still recommend it because I believe if we were in an environment that has industrial influence and have appropriate industrial material to work with then we can meet the standard of the growing industry of robotics.
TABLE OF CONTENT:
Introduction.
Overall task available.
Circuit diagram of the line follower robot.
Primary connection and testing using breadboard (prototyping).
PCB design (schematics and PCB layout).
Line tracking navigation of the LFR.
Diagram of the sensor position.
Motor type.
Steering method.
Chassis construction.
Final coupling and testing.
Conclusion.
INTRODUCTION
This is a simple mobile line follower robot (LFR) which is designed to follow black track (navigate through black track). The method or mode in which this robot navigates through the black track varies in speed depending on the complexity of the design. If the designer (engineer) decides to build a more complex circuit to control the robot either by using microcontroller and other programmable base component, then it will be able to control the speed of the robot while navigating through the black track but if a simple circuit (non-complex circuit) is used to build the robot then it will only navigates through the track with normal motor speed and hence no speed control and vise versa. This proposed line follower robot uses two sensors (left and right sensors) to differentiate between white and black surfaces in other to be able to navigate through the black surface. If the left sensor receive less light intensity, the robot will turn right (this means that the right sensor received more light intensity) but if the left sensor receive more light intensity, the robot will turn left (this means that the right sensor received less light intensity) and vise versa. The basic principal of the line follower robot actually almost the same as the light follower robot, but instead of tracking the light the LFR sensor is used to track the line, therefore by differentiating the line colour and it surrounding (white over black or vise verse) any light sensitive sensor could be used to navigate the mobile robot to follow this track. However the LFR is one of the most popular robot build by the robotics. What makes this LFR so popular?, this may be due to its simplicity and yet it could be used as the teaching tools of how we could implement the industrial standard control system such as the PID (Proportional Integral Deferential) control system on this robot. The successful implementation of this kind of line follower robot depends on the kind of engineers involved and how active their design and assembling of circuit component, testing process as well as troubleshooting processes.
OVERALL TASK AVAILABLE
Get specification.
Study and understand specification (analysis).
Design the robot circuit.
Bill of material (Bom), (materials required).
Assemble component (construct using breadboard).
Level test (verify if work according to specification).
Design PCB (printed circuit board).
Etching and drilling process.
Soldering of component onto circuit board.
Testing (initial testing)/ troubleshooting.
Design car and chassis.
Implement both designs.
Final testing and confirmation.
Finish robot (now working).
CIRCUIT DIAGRAM OF THE LINE FOLLOWER ROBOT
Figure1.
The 2N3904 NPN Bipolar Junction Transistor (BJT) is constructs to operate as the current gainer amplifier; this means we run the 2N3904 transistor in its linear region. The advantages of using the transistor in its linear region is; the transistor collector current passed through the DC motor, which vary according to the base current which is controlled by the LDR (Light Dependent Transistor) and 10 K trimmer potentiometer (trim pot). The trim pot is use to adjust the DC motor speed, while the 1N4148 diode is use to protect the transistor against the EMF (Electromotive Force) generated by the DC motor inductor when its switch off. The key of using this circuit successfully depends on the DC motor choice. Therefore the current through the DC motor will vary according to the light intensity received by the LDR.
PRIMARY CONNECTION AND TESTING USING BREADBOARD
The primary stage of the project where component need to be assemble using breadboard to test if the circuit designed above could actually be use to build the line follower robot (LFR) and moreover to verify if its work according to the specification given.
Figure2.
The primary connection was done as shown in the picture above and I supply 4.5 volt to the circuit after putting the motor in place and all other component connected therewith. I observe that it was working according to specification given and I proceed to PCB design immediately with the proposed circuit shown in figure1.
PCB DESIGN
Schematics diagram
Figure3.
The schematic diagram is as shown above, basically I use Dip trace to design the PCB and it was very challenging because some component were not found in its library so I choose any other components that has relative pin configuration and then add pattern to it from pattern.libs and change their values accordingly. However I converted the schematics to PCB but since Dip trace is not like Pcb wizard which has the capability to arrange the component in a unique way, so I arrange it manually and later run auto routing which make my pcb to look difference as compare to people that use PCB wizard.
Bottom view of PCB
Figure 4
The picture in figure 4 above is the bottom view of the PCB. This will be printed on board for etching which we need to used the etching chemical dissolve it in boiled water and put the board inside then shake it continuously until the outline peals off. The LFR car and chassis construction in this diagram is very simple as I just use a hardcore thick plastic measuring length 11.5cm and width 7.3cm for the main body construction and use caster (the third wheel) by using this easy to handle construction material, it was easy for me to build this line follower robot car and chassis, the finally coupling will seen in the other part of the picture below.
I use super glue to hold the 3 x AA (4.5 volt) battery holder and the micro DC motor, the DC motor also is reinforced with the plastic cable’s ties. The electronics component is soldered on the 5.5 x 3.5cm prototype PCB and I just use the mini-board to hold the LDR and LED together as shown on the picture below.
The picture on the right shows the side view of the car with one wheel and the mini board used to hold the sensors together on well placed position to the front of the car whereas left picture just shows the top view where you can see the battery holder and the two wheels in their fixed position.
FINAL COUPLING AND TESTING
This portion note down how the robot works and after the coupling we had some problem with our circuit but since the circuit was working initially we were a bit uncertain about where the fault could be because the sensors that were working stop working and motors is either one turn or both not turning and if both are turning it will be at high speed while the other at low speed, then we try to fixed motor problem and sensor problem. At this point we still couldn’t make it but later we discover that the transistor seem to be the entire problem in the circuit so we try changing the transistor and after changing the transistor with series of other circuit troubleshooting, the sensors and the two motor were working properly and I believe the transistor had some defect. Now our robot is ready to navigate through the black line.
The picture above show how the line follower robot navigates through the black surface. This actually means that we meet the requirement as stated in the specification, the robot simply follow the black line track.
CONCLUSSION
The project to design a line follower robot, though a simple project is actually very challenging as we really need to work hard in testing our circuit and have better troubleshooting technique that will help if any peripheral fell to work. However, for higher speed line follower robot with more complex track, we need to use the microcontroller, although it’s possible to use discrete electronics components but it required more complex circuit than the microcontroller based and transistor based which their solution become more simple and cheap to be used. For the transistor based circuit use in this line follower robot we iteratively check and troubleshoot the circuit component and test point although somewhat difficult to get it at first instance that we set on. After all the effort our project was successful and meet the requirement although it might not really meet the industrial standard but I still recommend it because I believe if we were in an environment that has industrial influence and have appropriate industrial material to work with then we can meet the standard of the growing industry of robotics.
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