Discussion on FASTBot sensor elements.
Sensors play a vital role in any robotic mechanism. Controllers of any robot get the knowledge on the operating environment using the sensing elements in different forms.
Naturally, FASTBot comes with suitable sensors to identify any obstacles, line sensors to track the given line, sound inputs as well as the light conditions. In this part, you can get to know all details of above sensing elements to undertake and finish many robotic tasks.
1. Line Tracking Sensors.
Line tracking sensors are built in the robotic trainer to offer a variety of maneuvers during experimentation. Basically these sensors identify a dark line in the white background or a white line in a dark background. Different operating environments can be created because of these line sensors.
Most of the time, the bot is required to follow the given line faithfully without any diversion. When the line contains many bends and turns, the control gets more complicated and becomes quite educating.
Since these line-sensing functions are widely used in the industrial applications, a good working knowledge on this line tracking can take you in the right path in your future adventures.
The line sensor is designed using Infrared Transmitter and the Phototransistor. These IR elements are kept close each other. During the usage, the transmitter is driven to emit the IR rays towards the target surface and the reflected rays coming out of that surface is captured by the phototransistor. White surface radiates most of the light and comparatively the dark surface radiates less light off its surface. So, you need to identify this difference and accordingly control rest of the bot elements to finish the job.
The FASTBot sports three sets of IR sensors to detect the given line. These sensors are mounted in a small PCB, which is fixed at the bottom of the bot for tracking the line.
So, we get the following signals when the bot travels over different surfaces:
On white surface : 0 level.
On dark surface : 1 level.
You can also note that there are three LEDs provided at the topside to indicate the track conditions for your visual confirmation. The LEDs will be turned on, when the sensors detect white and turned off when the sensors detect black.
2. Object Sensors.
Sensing the objects along the path is one of the features of the robot to undertake different applications. Robots can be programmed to avoid the obstacles along its path, navigate around the objects, follow the walls of the room and etc.
The object can be sensed by different ways. Some robots use contacts to “ feel “ the objects right on the track and sometimes robots tend to knock on the objects if the contact sensors are not properly managed. In general, bots get little time to react when using the contact sensors and the professional designers avoid using the contact sensors. So, non contact sensing is much preferred arrangement for the robots.
Again the IR sensors come to rescue the designers to implement a professional facility to sense and maneuver around objects in the paths of the robots.
FASTBot comes with IR object sensors manufactured by Sharp, Japan. The bot sports three sensors, two mounted in the side ways and the third one, sitting in the front looks for the obstacles right in the path of the robot. With these three sensors, the FASTBot can sense objects or obstacles around its path and can initiate interesting navigation around these obstacles.
These IR sensors contain both the IR transmitter and the respective phototransistor along with other signal processing circuits housed in a plastic case to form an integrated unit. The sensors can detect any object within the distance of 10 cm. So, with these sensors, FASTBot can identify any object in the vicinity of 10 cm around the bot in front and sideways. Since these sensors have better immunity to the ambient light, the robot can navigate around in a more predictable way than other options in most of the operating environments.
These sensors are marked as IR Object Left, IR Object Right and IR Object Front on the bot. Three separate LED indicators are also available to indicate output conditions for your visual confirmation.
3. Light Sensors.
The FASTBot sports advanced sensors to act on the light during its interaction with the given environment. These sensors come with special features to make the robotic interactions unique and interesting.
Most of the existing bots are designed with Cds (Cadmium Sulfide) cells to measure the intensity of light, taking more time to finish the task. This sensor does not give any linear output and not in any standard units. You also cannot use that sensor when you need accurate, fast calculations and fast maneuvers.
So, the FASTBot is designed with the state of art light sensors to bring fast reactions into applications. The semiconductor sensor, senses the light with 15 bit accuracy and it can handle the light intensity ranging up to 32,000 lux. The spectral sensitivity of this sensor matches with the human eye. It also rejects noises generated by 50 or 60 Hz flicker caused by the artificial lights.
Since it produces a digital value for the applied light, the interfacing of this sensor becomes little involved. The sensor is connected with the microcontroller using the type of serial port known as IIC bus. Two lines of this sensor are connected with two port lines of the controller for the communication. The lines are known as Serial Data Line (SDA) and the Serial Clock line (SCL).
FASTBot carries two light sensors mounted in the front side with the markings Left and Right sensors.
4. Sound Input and Output.
Most of the robots meant for study come with the facility to act on the sound inputs. With the “ears“ to sense the sound input, the robots demonstrate few interesting maneuvers in their applications.
FASTBot sports a high sensitive MIC to sense the given sound input and alerts the microcontroller to indicate the presence of the sound. Then the robot can react to the source of the sound or do something to acknowledge the presence of that sound input.
So, FASTBot can interact with the given sound inputs using the MIC as its sensing element. The bot also has the facility to generate sound signals using an onboard buzzer. You can generate the required tone of sound in your applications.
The high sensitive MIC is mounted on the top of the bot. It can sense loud sounds, claps and interrupts the controller for the reaction.
Interestingly, the sound input can be used to create intelligent responses when the bot is navigating through the given environment. Likewise, the bot can generate the sound tones to indicate its prowess.
5. Message Indicating Facility.
Like humans, robots also need to indicate messages about what they are doing or their point of view to the outside world. This kind of indicating facility is very much required during complicated applications. The bot can also indicate its progress through these messages to the human controller.
So, FASTBot has the facility to display up to 32 characters in two lines using standard LCD module mounted on the top. The bot can use this to indicate the error conditions, finished steps or even can ask you to do something when it gets into any trouble!
6. Push Button Switches and Point LED Indicators.
Robots use different sensors to interact with the given environment during navigation and take decisions based on how those sensors interpret the conditions prevailing all around the bot. These bots also have to manage their operators and should have the facility to interact with their human bosses.
So, like many professional robots, FASTBot also comes with switches and indicators to interact with you, the designer, who puts the bot into some task.
You can make the bot to do anything specific by triggering a key switch for the application in hand or expect the bot to indicate the condition when it successfully completes its defined tasks and etc.
FASTBot comes with three push button switches and six point LEDs for this need.
