CONSTRUCTION GUIDE Remote Big Wheel. Robobox. Level VIII

Transcription

1 CONSTRUCTION GUIDE Remote Big Wheel Robobox Level VIII

2 Remote Big Wheel In this box we will learn about an advanced use of motors and infrared emission & reception through a unique robot: the Big Wheel. Balancing between its two giant wheels, it will go faster than the previous robots and can be remotely controlled to do anything. Pièces 2X Big Wheels 1X Robobox Nano 2X Wheel Plugs 1X Mini USB Cable 1X Joystick 1X Clipper Instructions We suggest that you follow these instructions step by step. Additional details are available on your member space on Robobox.io. Please don t hesitate to ask any question, we will answer them promptly. Good luck!

3 _0_ 1NTR0DUCT10N The goal of our program will be to remotely control, through a Joystick, our Big Wheel. The communication between the Joystick and the robot will be done with infra-red. We have already seen in the past the principles of infrared communication, here we will go a little further by creating our own protocol. We will therefore develop a language that will be used to transport information from one card to another. Our goal will be to follow the process below: We move the Joystick 1 Position of joystick is saved in X & Y coordinates (between 0 and 1023) The position is converted into an infrared signal 2 3 Signal reception 6 Signal Emission 5 An 'identifier' is added so that our infrared signal to differentiate between X & Y 4 Position is converted Signal is decoded into action for the back into position 7 robot 8

4 Step 2 Step 1 _1_ EMISSION Pin3 GND-GND GND Our first circuit is quite simple. Here we will build the transmitter, a true remote control capable of transmitting the position of the joystick through an infrared LED. For this, we plug the NANO card on a mini Breadboard, then connect the IR LED on pin 3 (anode) and on the GND (cathode). Then we plug the GND on the GND, the 5V on the 5V, the X on the A3, the Y on the A2 and the SW on the A1. Our joystick is plugged in, now let's move to a more complex stage, sending the position of the joystick through the LED. #include <IRremote.h> IRsend irsend; void setup() { Serial.begin(9600); void loop() { int X = analogread(a3); int Y = analogread(a2); X = X/100; Y = Y/100; Crypt(X,'x'); Crypt(Y,'y'); At first and as usual, we will include librairies. Here we will add 'IRremote.h' for sending messages via infrared LED. As we did in month 5 we ll create an object called 'IRsend and initialize the communication in series in 'setup'. This serial communication will help us verify our code. Then we enter the 'loop' function, in this function, we read the position of the two axes of the joystick (x and y) thanks to 'analogread'. We will then send this position into a function which will be in charge of converting the position into an infrared signal and then send it, ie steps 3, 4 and 5 of the previous diagram.

5 step 3 void Crypt(unsigned int val, char axis){ unsigned int f1; unsigned int f2; int a = 0; unsigned int axiscode[3]; if (axis == 'x'){axiscode[0] = 300; axiscode[1] = 800; axiscode[2] = 300;; _1_ EMISSION This function is quite complex so we will go through it step by step. The Crypt function takes two arguments, an integer 'val' which contains the value of the position of the joystick and an 'axis' letter that tells us whether it is the x or y axis. if (axis == 'y'){axiscode[0] = 500; axiscode[1] = 300; axiscode[2] = 800;; if (val < 5){ f1 = 800; f2 = val+4; f2 = f2*100; ; if (val >= 5){ f1 = 400; f2 = val-1 ; f2 = f2*100; ; unsigned int envoisignal[10] = {5000, axiscode[0], axiscode[1], axiscode[2], f1, f1, f2, f2, 1000,500; while (a < 10){ Serial.print(envoiSignal[a]); Serial.print(','); a++; Serial.println(); irsend.sendraw(envoisignal,11,38); delay(100); id1 X or Y Position id2 & 3 Our signal must contain several pieces of information, first we must recognize it among other signals (remote controls, etc.) so we will use 'identifiers' (id1,2 and 3) to distinguish it. It must also communicate the position of the joystick and the X or Y axis this position relates to. Using the IR signal format, we will convert information into milliseconds, so the X-axis will be translated as 300, 800, 300 while Y will be translated as 500, 300, and 800. Then we will have to give the value of the position, that value will consist of 4 signals: - If the value is less than 5, 800, 800, (value + 4) * 100, (value + 4) * If the value is greater than or equal to 5, 400, 400, (value-1) * 100, (value-1) * 100. We thus find ourselves with a signal defined by 10 variables: id1, id2, id3, X/Y, X/Y, X/Y, posi, posi, posi, posi, id3 Now we just need to send this signal with irsend.

6 #include <IRremote.h> int RECV_PIN = 11; int MotorG = 5; int MotorD = 6; int Coordinate[2]; IRrecv irrecv(recv_pin); decode_results results; void setup() { Serial.begin(9600); irrecv.enableirin(); void loop() { if (irrecv.decode(&results)) { analyze(&results); irrecv.resume(); void analyze(decode_results *results) { int recieved[11]; int count = results->rawlen; for (int i = 0; i < count; i++) { recieved[i] = results->rawbuf[i]*usecpertick; _2_ RECEPTION if (abs(recieved[1] ) < 100 && abs(recieved[9] ) < 100 && abs(recieved[10] - 500) < 100) { char Axis = checkaxis(recieved); int Position = checkvalue(recieved); if (Axis == 'X'){Coordinate[0] = Position; if (Axis == 'Y'){Coordinate[1] = Position; Serial.print('['); Serial.print(Coordinate[0]); Serial.print('-'); Serial.print(Coordinate[1]); Serial.println(']'); Avance(Coordinate); Now that we have defined the emission, let's look at the code that will be executed on the other card, on the reception side. We first import the library for infrared communication. We then define the pin in charge of the data reception (11), then the pins for the left and right motors (5 and 6). As in box 5, we create an object for reception and one for value analysis. In the setup function, we just start the serial communication and initialize the object in charge of receiving the data. In the loop, we insert a condition: If we receive a signal, then we run the function analyze() and then we reset the receiver. As you can see, the function analyze() will be the core of our program. Its role will be to analyze the signal and translate it to an instruction to the car. First, we insert the complete signal in the variable 'recieved'. Then we check that it is indeed one of our signals. If it is one of our signals, we run two functions: checkaxis() to decode the joystick axis and checkvalue() to decode the position. We then display the position of the joystick and ask the car to act according to this information. We will now go through these 3 functions.

7 _2_ RECEPTION Now we will explain the two functions in charge of decrypting and extracting code: The axis and the position of the Joystick. char checkaxis(int *recieved){ int a = recieved[2]; int b = recieved[3]; int c = recieved[4]; int sumdiff = abs(a - 300) + abs(b - 800) + abs(c-300); if(sumdiff < 500){ return 'X'; else{ return 'Y'; ; int checkvalue(int *recieved){ int a = recieved[5]; int b = recieved[6]; int c = recieved[7]; int d = recieved[8]; if ( ((a+b)/2) >700){ return ((c+d)/2)/100-4 ; if ( ((a+b)/2) <600){ return (((c+d)/2)/100) +1; The checkaxis(int* recieved) function will identify the axis concerned. First, you will notice that this function has a rather special argument: (int* recieved), this is a pointer. In this case, the pointer is the link to the position in memory of the first value of the received list. We use a pointer because it is impossible under Arduino to pass an entire list through a function. In memory, the values in the list are placed one after the other, so we can access the rest of the list fairly easily. In a second step, we decrypt the axis. We read the 3 first elements of the list (the signals) that we used to encrypt the axis and we insert them into the variables 'a', 'b' and 'c. Finally, we calculate the absolute difference between these terms and the encryption for X, if the difference is less than 500 then this is the X axis, otherwise it is the Y axis: Signal received : X Signal : Difference = 100 -> Axis = X Difference = > Axis = Y The function checkvalue() works in the same way, this time the first two values 'a' and 'b tell us if the position is greater or less than 5 and the next two give the value of this position. For instance, if the mean of the first two numbers is greater than 700, we consider the value greater than 5. We then do the reverse of the encryption in step 3 : we withdraw 4 and multiply by 100. If the average of the first two numbers is less than 600 then the value is less than 5 and we perform the reverse of the encryption operation of step 3 by adding 1 and multiplying by 100.

8 void Avance(int* Coord){ int vit1 = Coord[0]; int vit2 = Coord[1]; int tempvit; int tempvit1; int tempvit2; if (vit1 >5 && vit2 ==5){ tempvit = map(vit1, 5, 10, 0, 255); analogwrite(motorg,tempvit); analogwrite(motord,tempvit); if(vit1 == 5 && vit2 == 5){ analogwrite(motorg,0); analogwrite(motord,0); if(vit1 == 5 && vit2!= 5){ if(vit2 < 5){ tempvit = map(vit2, 0, 5, 255, 120); analogwrite(motorg,tempvit); if(vit2 > 5){ tempvit = map(vit2, 10, 5, 255, 120); analogwrite(motord,tempvit); if( vit2!= 5){ if(vit1 == 5 && vit2 < 5){ tempvit = map(vit2, 0, 5, 255, 120); analogwrite(motorg,tempvit); if(vit1 == 5 && vit2 > 5){ tempvit = map(vit2, 10, 5, 255, 120); analogwrite(motord,tempvit); if(vit1 > 5 && vit2 > 5){ tempvit1 = map(vit2, 10, 5, 255, 120); analogwrite(motord,tempvit1); tempvit2 = map(vit1, 10, 5, 255, 120); analogwrite(motord,tempvit2); _2_ RECEPTION Finally, we will define the Avance() function. This function takes a list as argument, that contains the position of the joystick along the X and Y axes. The first value: Coord[0] contains the value of the X axis and the second Coord[1] contains the value of the Y axis. According to its values we can define a behavior. Let s consider some cases : [5,5] [10,5] [7,5] [5,10] When the joystick is in position [10,5], or in position [7,5], our robot must go forward proportionally to the value Coord[0], this is our first if condition. When the Joystick is at [5,5], nothing happens, it is at the center, this is our second condition. When the Joystick is at [5,10] it has to turn on itself at a certain speed, this is our 3rd condition. Finally, if none of our axis value are at 5 then the robot must rotate. Now that you have understood the logic of our program, let s build it!

9 Step 3 Step 2 Step 1 _3_ MONTAGE Insert the motors into the Motor Blocks from month 4. Insert the "Uno Card" into the "Cardholder" (CF: left diagram) and paste the "Mini-Breadboard" onto the "Boardholder". You will be able to hang these parts to the robot later. You can now plug in all these elements on the clipper. You will need to reuse parts from previous months like the battery block.

10 Step 5 _3_ MONTAGE Step 6 Step 4 GND-GND Connect two transistors on the breadboard, so that they share a common 'line on the breadboard. This line will be connected to the GND. The center pins of the transistors are connected to pins 5 and 6 of the UNO board. An IR receiver is connected to the other side of the board, connect the transistor s GND pin (center) to the central line of the transistors. Connect its right pin to 5V line and its left pin to pin 11. Finally connect the left line of the breadboard to the GND. 5V 5-T1 6-T2 T1-Mot1- T2-Mot2-5V-Mot2+ 5V-Mot1+ OUT-11 5V-5V Connect the common transistor line to the GND, then connect the free pins of the transistors to the motors and the 5V line of the breaboard to the other poles of the motors. Finally, add the wheels mounted on their axes to the robot.

11 7 _3_ MONTAGE

12 _3_ MONTAGE CHALLENGE Our robotis now assembled, have fun driving it around We now have many challenges to offer, the most important pertains the Avance' function. -> Create a simpler Avance' function without using any If. Good luck!

13 _4_ NOT3S

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