Assembling the robot and reviving the board

What should a robot do. First, the robot needs to correctly execute individual commands: rotate each wheel, stop and report sensor readings. Before our independent trip, we will check each component in turn to look for the cause of the error in one place.

What we use and how it works. Arduino Uno is executing the program. The L298P driver uses its signals to control the power supply to the motors: the DIR pin sets the direction, PWM - the proportion of power supply time. The motor converts electrical energy into rotation, and the wheel into movement. Two reflection sensors on the bottom help distinguish between a light surface and a black line.

How to link a dimension to an action. The command and the result are two different things. The inscription in the monitor means that the program has reached printing; We check the rotation with our eyes. On the stand, we will check both directions of each wheel and the stop, then compare the readings of the sensors above the white and black cards. This way we’ll find out exactly how our robot is assembled.

You are working together. One - Pilot: holds parts and a screwdriver. Second - Navigator: reads the step out loud, provides the details and checks the result using the picture.

1. Decide who starts as Pilot.
2. After each part that is secured with screws, switch roles.

Find every part before assembling. This way you won’t confuse similar parts and will immediately see if something is missing.

Base 130 × 150

1 pc.

Motor bracket

1 pc.

Motor bracket (mirror)

1 pc.

Sensor strip

1 pc.

Arduino holder

1 pc.

Switch mounting

1 pc.

Wheel

2 pcs.

1. Arrange the printed parts in a row, like on cards.
2. Find two motor brackets. They are similar, but mirrored: put them side by side and look - the shelves face in different directions.
3. Place the purchased parts nearby: Arduino, motor shield, two motors, a ball joint, two line sensors, a battery compartment and bags with fasteners.

Almost all parts of the robot are held on by screws and nuts. Let's assemble one connection on the table.

1. Take a screw, two washers and a nut from the Training bag.
2. Place the washer on the screw, slide the screw through the two pieces, put the second washer on and screw the nut on with your fingers.
3. Hold the nut with your finger and tighten the screw with a screwdriver. Stop as soon as the parts stop moving.

So that “left wheel” always means the same thing, let’s mark the front of the robot.

1. Lay the base flat: a small square window is further away from you, a long rectangular window is closer.
2. Far side - before. Stick a paper forward arrow on it.
3. Define left and right as the driver who sits in the robot and looks in the direction of the arrow.

Brackets hold the motors from the bottom of the base.

1. Turn the base over so that the arrow remains visible from the side.
2. Place the brackets on the bottom side as shown. Big round holes look out out - the wheel axles will go there.
3. Insert the screws from above and fit the washers and nuts underneath. Start all screws loosely by hand, then tighten them.

The motor axis is a rotating rod on which the wheel fits. It should come out through the hole in the bracket.

1. Attach the first motor to the bracket from the inside. The axis passes through a large hole outward.
2. Secure the motor with the screws from the Motors package. Hold the motor with your hand while you tighten it.
3. Also install the second motor.
4. Label the wires: L - left motor, P - right. Check the forward arrow.

1. Align the wheel hole with the motor axle. The shape of the hole must match the shape of the axis.
2. Put the wheel on while holding the motor by the housing. Don't hit the wheel.
3. Look from the side: the wheel should not touch the bracket or base.

There are two wheels, so the robot needs a third support point at the back - a ball joint.

1. Attach the ball joint from below to the back side of the base. The racks from the “Support” package are selected in height.
2. Place the robot on the table. It should stand exactly on two wheels and a support.
3. Gently rock the robot. Nothing should be loose.

Arduino is the “brain” of the robot. The board lies on the holder so that its contacts from below do not touch the screws.

1. Secure the Arduino holder in the center of the base with the posts facing up.
2. Place the board on the stands so that the USB connector is at the edge and can be reached.
3. Secure the board with screws. Tighten them one by one, little by little.

Upload an empty sketch and read the message about the successful upload.

void setup() {} void loop() {}

This tests the board, USB connection and uploading. It does not yet establish that the motors, shield, sensors or mechanical assembly work correctly. We will test their operation after connecting all components.

Arduino pins cannot supply enough current to motors. Therefore, the motors are connected to shield - a board that is placed on top of the Arduino and turns on the motors according to its commands.

1. Align the shield legs with the Arduino sockets and gently press on top. No leg should be left out or bent.
2. Connect the motor wires to the shield terminals:

3. The battery compartment with the switch is already connected by an adult. Check that the switch is off. If the compartment wires are not connected, do not connect them yourself, call an adult.

Line sensors will "look" at the floor and notice a black line. We place them in front, across the robot.

1. Attach the sensor strip from the bottom at the front edge of the base to the posts.
2. Attach two sensors to the bar - left and right - with the sensitive side down, to the floor. The sensors are at the same height.
3. Connect the sensors to the shield according to the table. The letters of the sensor contacts are: S - signal, V - power, G - ground.

4. Lay the wires so that they do not touch the wheels.

Now let's check that every part of the robot works: both wheels and both sensors. The verification program is already open in the editor on the right.

// Программа проверки для робота курса (Arduino Uno + шилд L298P).// Робот стоит на подставке: колёса висят в воздухе.// Колесо крутится со скоростью 120 из 255 около 0,3 секунды.const int LEFT_DIR = 7;const int LEFT_PWM = 6;const int RIGHT_DIR = 4;const int RIGHT_PWM = 5;const int LEFT_SENSOR = A4;const int RIGHT_SENSOR = A5;const int FORWARD = HIGH;const int BACKWARD = LOW;const int TEST_PWM = 120;const unsigned long PULSE_MS = 300;bool running = false;unsigned long startedAt = 0; void reportSensors() {  Serial.print("LEFT=");  Serial.print(analogRead(LEFT_SENSOR));  Serial.print(" RIGHT=");  Serial.println(analogRead(RIGHT_SENSOR));} void beginPulse(int dirPin, int pwmPin, int direction) {  digitalWrite(dirPin, direction);  analogWrite(pwmPin, TEST_PWM);} // ===== Готовая оболочка — не меняй =====void stopMotors() {  analogWrite(LEFT_PWM, 0);  analogWrite(RIGHT_PWM, 0);  running = false;} void setup() {  pinMode(LEFT_PWM, OUTPUT);  pinMode(RIGHT_PWM, OUTPUT);  stopMotors();  pinMode(LEFT_DIR, OUTPUT);  pinMode(RIGHT_DIR, OUTPUT);  pinMode(LEFT_SENSOR, INPUT);  pinMode(RIGHT_SENSOR, INPUT);  Serial.begin(9600);  Serial.println("READY: 1=L forward, 2=L backward, 3=R forward, 4=R backward, d=sensors, s=stop");} void loop() {  if (running && millis() - startedAt >= PULSE_MS) {    stopMotors();    Serial.println("PWM=0; verify physical stop");  }  if (!Serial.available()) return;  char command = Serial.read();  if (command == 's') {    stopMotors();    Serial.println("PWM=0; verify physical stop");    return;  }  // Пока идёт импульс, новые команды не продлевают и не перезапускают его.  if (running) return;  if (command == 'd') {    reportSensors();    return;  }  if (command < '1' || command > '4') return;  // Удаляем накопленные команды: один ввод не должен запускать очередь движений.  while (Serial.available()) Serial.read();  stopMotors();  startedAt = millis();  running = true;  if (command == '1') beginPulse(LEFT_DIR, LEFT_PWM, FORWARD);  if (command == '2') beginPulse(LEFT_DIR, LEFT_PWM, BACKWARD);  if (command == '3') beginPulse(RIGHT_DIR, RIGHT_PWM, FORWARD);  if (command == '4') beginPulse(RIGHT_DIR, RIGHT_PWM, BACKWARD);  Serial.println("Observe wheel; no automatic hardware PASS");}

// Программа проверки для робота курса (Arduino Uno + шилд L298P).// Робот стоит на подставке: колёса висят в воздухе.// Колесо крутится со скоростью 120 из 255 около 0,3 секунды.const int LEFT_DIR = 7;const int LEFT_PWM = 6;const int RIGHT_DIR = 4;const int RIGHT_PWM = 5;const int LEFT_SENSOR = A4;const int RIGHT_SENSOR = A5;const int FORWARD = HIGH;const int BACKWARD = LOW;const int TEST_PWM = 120;const unsigned long PULSE_MS = 300;bool running = false;unsigned long startedAt = 0; // ===== Твоя часть =====void reportSensors() {  // Цель: показать в мониторе подписанные показания левого и правого датчиков.} void beginPulse(int dirPin, int pwmPin, int direction) {  // Цель: включить только указанный мотор с указанным направлением и TEST_PWM.} // ===== Готовая оболочка — не меняй =====void stopMotors() {  analogWrite(LEFT_PWM, 0);  analogWrite(RIGHT_PWM, 0);  running = false;} void setup() {  pinMode(LEFT_PWM, OUTPUT);  pinMode(RIGHT_PWM, OUTPUT);  stopMotors();  pinMode(LEFT_DIR, OUTPUT);  pinMode(RIGHT_DIR, OUTPUT);  pinMode(LEFT_SENSOR, INPUT);  pinMode(RIGHT_SENSOR, INPUT);  Serial.begin(9600);  Serial.println("READY: 1=L forward, 2=L backward, 3=R forward, 4=R backward, d=sensors, s=stop");} void loop() {  if (running && millis() - startedAt >= PULSE_MS) {    stopMotors();    Serial.println("PWM=0; verify physical stop");  }  if (!Serial.available()) return;  char command = Serial.read();  if (command == 's') {    stopMotors();    Serial.println("PWM=0; verify physical stop");    return;  }  // Пока идёт импульс, новые команды не продлевают и не перезапускают его.  if (running) return;  if (command == 'd') {    reportSensors();    return;  }  if (command < '1' || command > '4') return;  // Удаляем накопленные команды: один ввод не должен запускать очередь движений.  while (Serial.available()) Serial.read();  stopMotors();  startedAt = millis();  running = true;  if (command == '1') beginPulse(LEFT_DIR, LEFT_PWM, FORWARD);  if (command == '2') beginPulse(LEFT_DIR, LEFT_PWM, BACKWARD);  if (command == '3') beginPulse(RIGHT_DIR, RIGHT_PWM, FORWARD);  if (command == '4') beginPulse(RIGHT_DIR, RIGHT_PWM, BACKWARD);  Serial.println("Observe wheel; no automatic hardware PASS");}

// Программа проверки для робота курса (Arduino Uno + шилд L298P).// Робот стоит на подставке: колёса висят в воздухе.// Колесо крутится со скоростью 120 из 255 около 0,3 секунды.const int LEFT_DIR = 7;const int LEFT_PWM = 6;const int RIGHT_DIR = 4;const int RIGHT_PWM = 5;const int LEFT_SENSOR = A4;const int RIGHT_SENSOR = A5;const int FORWARD = HIGH;const int BACKWARD = LOW;const int TEST_PWM = 120;const unsigned long PULSE_MS = 300;bool running = false;unsigned long startedAt = 0; // Напиши диагностику по требованиям урока. При включении моторы стоят.void setup() {  pinMode(LEFT_PWM, OUTPUT);  pinMode(RIGHT_PWM, OUTPUT);  analogWrite(LEFT_PWM, 0);  analogWrite(RIGHT_PWM, 0);} void loop() {}

How to check a robot

1. Check the wires. The motor switch is off. Check the wires with the connection tables: each one is in its place and does not touch the wheels. The wheels rotate freely by hand.
2. Upload the program. Click Upload to robot. Open downstairs Serial Monitor at 9600 speed. The line READY - the board responds. Press the Reset button on the board: the wheels stop.
3. Check the sensors. Submit d and read the two numbers. Place white paper under the left sensor and send d, then black - and again d. Do the same with the right sensor. On white and black, the numbers should be noticeably different.
4. Check the wheels. Turn on the motor switch. Send 1 and look at the wheels: only the left wheel turns forward briefly and stops itself. Then send one by one 2, 3 and 4.
5. Check the stop. Submit 1 and immediately s - the wheel stops. Turn off the motor switch and send 1 once again: the wheels don't spin.
6. Write down the result to log for each component from the table: command, response in Serial Monitor and actual rotation or sensor reading. If the component has not yet been verified, write down “not verified.” If something is wrong, turn off the motor switch, disconnect the USB, open “If it doesn’t work”, fix it and check this unit again.

1. Write down the date, the robot's name and what happened today in the logbook.
2. Note which components passed the test immediately and which ones you corrected.
3. Save the check program - it will come in handy if the robot starts behaving strangely.