Bài 5: Lập trình Robot giáo dục KCbot và cảm biến siêu âm

Hello teachers and students Welcome back to STEM Science Robots and Autonomous Vehicles I'm Hoang Van Dong, founder of Kikko STEM Continuing from the previous lesson, today we will move on to the 4th lesson with the theme of Robots Avoiding Obstacles Using Supersonic Sensors In this 4th lesson, we will have 3 sessions In each session, we will focus on one aspect of the theme of Robots Avoiding Obstacles Using Supersonic Sensors In the first session, we will focus on learning about supersonic sensors, their principles and supersonic sensor modules and use them to make a simple robot avoiding obstacles In the 2nd session, we will use a lot of supersonic sensors at once to make the robot avoid obstacles more flexibly In the 3rd session, we will learn about Robots Avoiding Obstacles Using Supersonic Sensors Combined with Supersonic Motors That is, we only use one supersonic sensor combined with a supersonic motor to rotate corners to find the way That is the content of the 3 sessions in the 4th lesson In this session, we will focus on the first topic, which is Supersonic Sensors and Robots Avoiding Obstacles The content of today's lesson has 3 parts The first part is to learn about the concept of supersonic sensors Next, we will learn about the operating principles of supersonic sensors and then we will proceed with the process to make the robot avoid obstacles using supersonic sensors The first part is about supersonic sensors As everyone knows, animals use supersonic sensors In the daytime, we can see with our eyes, but at night, we will use our nose or mouth to detect insects In the seabed, there is not much light, so we have to use a supersonic signal to detect small fish We humans also know how to use supersonic sensors to locate submarines These are some typical applications of supersonic sensors This application is called echolocation In English, echolocation means echo In Vietnamese, we call it echo Echolocation is the use of sound waves and echo to locate objects in space For example, if you want to locate an insect, it will emit a supersonic wave When interacting with an insect, this supersonic wave will send a feedback wave The drone will be able to calculate the distance from itself to the insect Therefore, it applies the principle of positioning by sound The drone uses this ability to locate and locate food in the dark To have sound, the drone will send a sound wave from the mouth or nose The frequency can be different Normally, to create a sound wave, the drone emits a sound with a proper frequency When concentrating on the insect, the drone emits a supersonic wave with a higher frequency to be able to detect the insect When the supersonic wave touches an object, it will reflect back and create a sound This is the principle of echolocation If you pay attention, you will find that the blind often have a better perception than the average person Because the blind also uses the principle of echolocation to locate objects in space In fact, because we are used to the sound, we do not pay attention If we turn off all the sound in this space, we will not be able to locate our space There is a video that you can watch on YouTube Without sound, it is very difficult to locate space We also know that the supersonic wave has a higher frequency than our sound Our sound is the green line here It ranges from 20Hz to 20kHz Includes humans and pets in the house Between 20Hz and 20kHz, we call it a sound Electron is an elephant, it can emit and hear the sound And larger than 20kHz, we also have a yellow line, which is the supersonic wave Electron is an elephant, it can emit and hear the supersonic wave A very important example of supersonic wave is in medicine We often use supersonic waves to check our health That is the general principle of supersonic waves Next, I would like to introduce the supersonic sensor On the screen, you can see the image of a very common supersonic module Named SC-SR04 In addition to this SC-SR04 module, there are other models on the market Such as SC-SR05, SC-US05, etc. However, all of these sensors are different in accuracy and range However, we will use SC-SR04 SC-SR04 sensor module uses supersonic waves To determine the distance without having to touch an object Like the way Mr. Roi and Ms. Ao did above This module is not affected by sunlight Or affected by a black material Compared to other modules that we often use as external sensors It is affected by sunlight This supersonic module is not affected by sunlight Usually, a supersonic module will have a pair of tools and supersonic waves As you can see on the screen The supersonic wave set includes It is marked next to the letter T The principle of the word is TRANSMIT And the supersonic wave receiver is marked with the letter R Which is RECEIVE Each module usually has 4 pins The first pin is VCC It is the power supply for the module The power supply here is VCC, so we will supply 5V The next pin is TRIG It is the IN pin, which is the input pin of this module When this pin receives a square wave It will activate the T pin here to generate a supersonic wave The next pin is ECHO It is the OUT pin of this module This pin will tell us that there is a supersonic wave When this pin emits and hits a white object It will reflect back When this receiver receives that reflection signal This ECHO pin will tell us And the last pin is GND It is the ground pin in the power supply That is the structure of the supersonic wave module Some notes and some parameters of the supersonic wave module We need to pay attention to First, the physical size of the supersonic wave module 15mm, 43mm and 20mm In length, width and height However, there is a parameter that we need to pay attention to That is the operating angle Or the operating market of the supersonic wave module That market is at 30 degrees The best in 30 degrees It means that in the objects at 30 degrees This supersonic wave module is the best And all the objects outside Our supersonic wave module will not be able to detect This leads to the third article We will attach a servo motor to rotate this angle Rotate the supersonic wave module It may expand the supersonic observation market We will discuss in the third article There are two points When we supply power, we remember to supply the GND pin first When supplying the VCC pin And the surface of the object that we need to measure the distance Should have an area of ​​at least 0.5 square meters To work best However, in practice, I find it smaller It can still be relatively stable But this is an advice from the manufacturer Some other technical parameters of the supersonic wave module That we need to pay attention to The power supply is 5V and above The current when not in operation will be less than 2mA The current when the supersonic wave module is in operation is 15mA This parameter is only needed when we design the circuit When we design the circuit, we need to pay attention to these parameters 15mA The operating angle is 15 degrees The measurement distance is from 2cm to 400cm Which is about 4m The width is 0.3cm We can measure distances of 2cm, 2.3cm, 2.6cm, 2.9cm, etc. Up to 400cm That is the width The measurement angle is 30 degrees As I analyzed above The thickness of the spring that enters the trigger leg Is at least 10μs That is, we need to put a spring of about 10μs into this leg Then the supersonic wave is emitted at this face If it is smaller, the supersonic wave will not be emitted at this face That is, it has not been activated yet The size is 45mm x 20mm x 15mm These are the technical parameters of this supersonic wave module Now let's move on to how to make the supersonic wave module Can measure the distance from it to the object without contact This is the formula that helps us calculate As you know, the supersonic wave module has two faces One emitting and one receiving The principle is very simple When the emitting face emits a supersonic signal This supersonic signal will hit the object And there will be a feedback wave That is, an echo When the feedback wave returns, the receiving face will receive This signal is based on that feature that people calculate as follows Suppose d is the distance that we need to find From the supersonic wave module Or our robot To the object And t is the time that the supersonic wave transmits from the emitting face In the emitting face until it receives the receiving face These are the two parameters that we have named here So we will have S is the path of the supersonic wave As we have just analyzed above The supersonic wave will go from the emitting face to the object Then return So S will be equal to 2 times d One turn to and one turn back On the other hand, we also have S by V times t According to the formula, the path is the speed factor times time In which V is the speed of the supersonic wave The speed of the supersonic wave is also the speed of sound Equal to 344 meters per second And 0.0344 cm per second By combining these two formulas We will have 2 times d by S And V times t Substitute above From there we will get d It will be equal to 0.0344 times t Divide by 2 And it is equal to t Divide by 58 Where d is calculated in centimeters And t is measured in microseconds So to find d We just have to find t That is, the time that the supersonic wave From the emission to the return Knowing t, divide by 58 We will get the distance Distance from the supersonic module to the object That is the operating principle of the supersonic sensor module In the control process We have to do it step by step However, with the linear program It is very simple We just need to draw a line to measure this distance All the image formulas Have been hidden In the Hiscope software And in the program code If you want to find out You can open the C program Some notes When we use the supersonic sensor Especially when we arrange it Sometimes this feeling It is not accurate Because of the following reasons For example, the first case The object is too far Compared to this module Here you see It is larger than 3.3 meters It has reduced the accuracy According to the parameters of the manufacturer It is 4 meters But in fact, when measuring It is about 4.5 meters It can still be measured The best accuracy is within 3.3 meters The second case The surface of the object It is not perpendicular With our supersonic module Like this Then we can immediately understand If the theta angle is less than 45 degrees Then the wave It will not be reflected back And it will dissipate like this Leading to no feedback This is the second case We can't measure the distance The third case The object in front of the eye It is too small This is easy to understand If we send it out There is still a reflection But its frequency is small It will lead to no feedback The fourth case The object is too soft Or hollow Like this It can also reduce the accuracy The result is When we measure We need to be careful Next day We will have a competition Using this supersonic module To go over a box Or a maze The maze itself Will have to avoid materials Too thin or too thick Like this When you measure You have to make this eye Try to be square So that the object Or at least check a moderate degree Then our module can recognize The reflection back I want you to pay attention to this point Because the sensor Measure the initial value It determines the entire process The third part We will move to Process for Robot to avoid materials Using supersonic sensors This is our box Our robot On the box You still have 2 modules M1 and M2 Our supersonic sensor module Will plug into the plug We also see there are 4 wires Because it is standard We will not be afraid of each other We also have VCC Trigger Trig Echo GND This is the design On this leg Trig leg We are already connected to leg 2 Echo leg We are already connected to leg 12 In the process We have to choose the correct leg 2 and leg 12 If we don't want to use these 2 legs We have to plug this supersonic sensor Out of the other legs And not plug here In practice, we just need to take this wire Hold it straight here We can run In this case We will use a simple command Read distance This command will return the distance From the robot To the robot's eye object Length from 2 cm to 400 cm Here you can see Number 2 and number 12 Number 2 is the trigger Trig Echo GND We are already connected to leg 12 So we only need to plug in 2 numbers All of these commands Will return the value Distance from the robot To its eye object In the measurement of the supersonic sensor Our task In this lesson There will be 3 tasks The first task is to read the distance from the supersonic sensor And send the read value To the computer screen To read the distance from the supersonic sensor We just need to pull this command And to send it to the computer screen Why do we have to send it to the computer? Because we want to observe the data But we need a screen to see The most convenient is the computer screen To send data To the computer screen We will use 2 commands 2 blue commands The first command is Set the mode for communication Between robot and computer Set the serial speed 9600 bits per second This is the first command The second command is Serial in In our communication If there is any data We will print it on the screen What is our data? It is the distance The distance from the robot to the sensor We will send the distance To the computer screen By this command You just need to pull a program like this And you put your hand On the supersonic module The speed will change That is the first task The second task is We need to schedule for the robot to work If there is no sensor We will move forward If there is a light, we will stop If there is a sensor We will stop That is the program I will analyze the program first And we will do it later If the distance We can read the distance If the distance from the robot to the sensor Is greater than 2.5 cm That is the distance We will continue to move forward If the distance From the robot to the sensor Is less than 2.5 cm We will stop That is the next example The third task We will increase a little The second task If we don't stop We will continue to move forward And move It is similar to the above command But now we will add Another command If the distance Is greater than 2.5 cm We will continue to move forward If the distance is less than 2.5 cm We will stop Then we will move the robot To the sensor These are simple examples To make a robot To the sensor In the second and third tasks We will go deeper In the sensor Now we will simulate The robot We invite you to watch The video we have prepared Today we will go to the simulation task Simulate the robot to the sensor First we will simulate The robot to the sensor Open the simulation file We have done in the power tab This is the engine simulation file We will continue to use In this simulation file, we have the engine simulation And the sensor We need another sensor We will find V and find Ultra We will go to the Steam Education Box We will get the UltraSolid This is our sensor We put it out Here In the power tab The sensor is connected to the number 2 and the number 12 The particle is equal to the number 2 And the electron is equal to the number 12 We will connect Electron is equal to the number 12 And the particle is equal to the number 2 To simulate, we do not need to connect 5V and GND To simulate the action of the sensor We need a resistor We will find V We call it VHT We will use VHT We will take it out This is our resistor We use 1K You will connect the resistor to the SIM pin We will connect the power to the ground of the resistor The connection is complete The connection is still hard To run the simulation of our sensor To run the simulation of our sensor You will need to run the hack for this sensor You click on the sensor image In the UltraSolid.hack Click and choose In our library You type in kitcode.edu.vn You open it You will see a file called UltraSolidSensor.hack You click on it And open That's it We have finished Connecting and running the hack for the sensor Now we run the simulation with the K4 machine Next, you will open the simulation file and type the code Now we run the simulation In the first step We will send the data of the sensor to the transmission port of the robot We will display the distance on the computer screen You will see here We will have a transmission port You will get the password The speed of the load is 300 The speed of the load We can use different speeds But the usual speed is 9600 You will choose 9600 Next You will get the starting block In the KC4 port You go back to the transmission port Get the zero-in command Click on the start button And what to print We will print the value of the beam The value of the beam We will read in the KC4 port You find the command The distance between the feet is 2 And the number of feet is 12 From the feet We will print the value of the beam You will combine the command and the zero-in command When you put the command close to the beam You will see the light and the music The two commands will be combined as you see on the screen Next, we will add a command We will wait for 1 second We will display once Wait for 1 second OK, we have finished the data transfer of the beam to the computer Now we will do the translation You wait for the translation of our code So it should be successful Now we will go back to the simulation You go to the stem education board Then in the program file You choose the simulation OK And In order to receive the data that Microsoft sends We need a terminal In the simulation We will zoom in in this part like a pin Choose the visual terminal and choose the visual terminal Then you will go here Our x-axis and x-axis x-axis we go to x-axis of the terminal and x-axis we go to x-axis of the terminal Tx is for transfer and Rx is for receive Transfer we go to receive and receive we go to transfer Then we are done Now we will go to the room You see here Now I will change the way You see here We will receive the value of the beam when this percentage is less than 40 years Gradually You will notice that the value of this side will gradually decrease The value of this side is 1 cm I will reduce it to 10% As you can see here when I reduce it to 10% The value we receive is only 111 cm We reduce it to 5 We only have 55 cm So Our simulation program has been successful Now we will load the program into the robot to see how it works Now we will connect the robot to our computer Connect Connection And you will load the program As you can see here We have finished loading the program Now to check You will go to the tool of the tool software This is the part to receive the data from the robot The load speed here As you can see in the software The speed is 9.6 You choose 9.6 Plus You choose the robot combo Connection As you can see here The value we receive is the value of this side Now we will change the value I will reduce it to 8 As you can see here The value we receive is only 4 cm This distance is the distance from the edge of our whiteboard So we can use this distance to check if the robot is touching the whiteboard Check if the robot is touching the whiteboard So we have just completed the simulation and simulation for the robot to send data from the whiteboard to the computer Now we will perform the second task which is to simulate for the robot When the robot touches the whiteboard The robot will stop and turn to the left The left side is our M1 Now our simulation will not change anything Because we already have the engine Camtasia and PowerMax Now we will do the simulation Here we already know that the distance is the distance from the edge of the whiteboard to the computer Now we will change the value I will reduce it to 8 As you can see here The distance is the distance from the edge of the whiteboard to the computer Now we will change the value I will reduce it to 8 If the value we get is less than 30 That is, there is a edge in front of it then it will stop Now we continue to the logic command We will take an arrow You will paste it in the command If it is done, you move it closer and release it The arrow here we will take is a bigger arrow You click on the arrow We will take a bigger arrow This is the value of the arrow we received It is the command to read the distance And the rest we will take in the math part We will take the number 0 and change it to number 30 That is, if our distance is greater than 30 Then we will just go We will just move the arrow forward and paste the number 4 Take the command to move the arrow And we have measured 200 You just know how to create Here If the distance is less than 30 Then we will stop the robot Here we will take the command Stop moving At the bottom, stop moving You paste it here We have finished the robot If there is no obstacle, then continue If there is an obstacle within 30 Then it will stop Now we will start Now we will go back to the room You see here Now I will continue to run the room Now we don't need this anymore We can delete it As you can see here, as I said earlier 5% is equal to 50 Now I will lower the center 2% As you can see here 2% is equal to 20 cm Then our robot will stop If our robot is smaller than 30 Then it will stop Now I will increase the distance 30 Then the robot will start moving As you can see The robot has started moving And if there is an obstacle For 20 cm Then it will stop But our request is to fix the robot When there is an obstacle Stop and turn it to the left Here We will take one more command We will let the robot stop in the room 200 ms Then let the robot turn left 300 ms I will continue to cut the code Here you can see Turn left We can increase the speed to 100 Continue to turn left 200 ms I will stop And then we will run the room As you can see here You can see that the robot has just stopped We will let the robot turn left Because we just want to stop The distance here is only 20 cm I will increase the distance As you can see, the robot has turned forward And when stopping And when the distance is smaller than 20 cm And when the distance is smaller than 30 cm The robot will immediately stop And the robot will turn left So we have successfully finished the room Now we will run on the real robot We will run this program on the robot 5 robots Including the robot And the program As you can see The program is successful Now we will run Hello everyone Good night See you again in the next part