Analog signal to enable DC motor for set time

Using Arduino Programming Questions
1

I am currently working on a prosthetic hand and I need a normal brushed DC motor to be able to spin for a set amount of time at a set speed. I am using arduino uno and L293d H-bridge. The control of the motor is based on a signal acquired from an sEMG sensor. I am new to working with arduino and would appreciate some help.

When I run the code, I receive these error messages:

move_motor_for_set_time:49:3: error: 'oldState' does not name a type
oldState = EMGsig;
^~~~~~~~
move_motor_for_set_time:50:3: error: expected unqualified-id before 'if'
if (digitalRead(Pin1 == HIGH))
^~
move_motor_for_set_time:61:3: error: 'Serial' does not name a type
Serial.print(EMGsig);Serial.print(" EMG reading, with voltage: ");Serial.println(voltage);
^~~~~~
move_motor_for_set_time:61:24: error: 'Serial' does not name a type
Serial.print(EMGsig);Serial.print(" EMG reading, with voltage: ");Serial.println(voltage);
^~~~~~
move_motor_for_set_time:61:69: error: 'Serial' does not name a type
Serial.print(EMGsig);Serial.print(" EMG reading, with voltage: ");Serial.println(voltage);
^~~~~~
move_motor_for_set_time:63:3: error: 'motorSpeed' does not name a type
motorSpeed = analogRead(potPin) / 4;
^~~~~~~~~~
move_motor_for_set_time:65:1: error: expected declaration before '}' token
}
^
exit status 1
'oldState' does not name a type


const int Pin1 = 12; // connected to pin 7 on the H-bridge
const int Pin2 = 11; // connected to pin 2 on the H-bridge
const int enablePin = 3;   // connected to pin 1 on the H-bridge
const int potPin = A0;  // connected to the potentiometer's output

int motorSpeed = 0; // speed of the motor
int threshold = 90;  // Move the motor when EMG signal is above this threshold. Remember it ranges 0–1023.
int oldState = 0;

unsigned long startTime;

void setup() 
{
  Serial.begin(9600);
  
  pinMode(Pin1, OUTPUT);
  pinMode(Pin2, OUTPUT);
  pinMode(enablePin, OUTPUT);
  
  
  //pinMode(motorPin, OUTPUT);      
  //pinMode(sensorPin, INPUT);     
}
//
void loop()
{
  //int sensorState = digitalRead(sensorPin);
  int EMGsig = analogRead(A5);
  float voltage = EMGsig * (5.0 / 1023.0);
  
  if (EMGsig > threshold) //voltage must be tuned according to sEMG output
  {
    if (oldState > threshold)
    {     
      Serial.println("Button Pushed");
      digitalWrite(Pin1, HIGH);
      digitalWrite(Pin2, LOW);
      analogWrite(enablePin, motorSpeed);

      }   // turns the motor on
      startTime = millis();
    } 
  }
  oldState = EMGsig;
  if (digitalRead(Pin1 == HIGH))
  {
    if (millis() - startTime >= 5000UL)
    {
      Serial.println("Timer Expired");
      digitalWrite(Pin1, LOW);
      digitalWrite(Pin2, HIGH);
      analogWrite(enablePin, 0);

    }
  }
  Serial.print(EMGsig);Serial.print(" EMG reading, with voltage: ");Serial.println(voltage); 

  motorSpeed = analogRead(potPin) / 4;
  
}```
2

Try it like this?

const int Pin1 = 12; // connected to pin 7 on the H-bridge
const int Pin2 = 11; // connected to pin 2 on the H-bridge
const int enablePin = 3;   // connected to pin 1 on the H-bridge
const int potPin = A0;  // connected to the potentiometer's output

int motorSpeed = 0; // speed of the motor
int threshold = 90;  // Move the motor when EMG signal is above this threshold. Remember it ranges 0–1023.
int oldState = 0;

unsigned long startTime;

void setup()
{
  Serial.begin(9600);

  pinMode(Pin1, OUTPUT);
  pinMode(Pin2, OUTPUT);
  pinMode(enablePin, OUTPUT);


  //pinMode(motorPin, OUTPUT);
  //pinMode(sensorPin, INPUT);
}
//
void loop() {
  //int sensorState = digitalRead(sensorPin);
  int EMGsig = analogRead(A5);
  float voltage = EMGsig * (5.0 / 1023.0);

  if (EMGsig > threshold) {   //voltage must be tuned according to sEMG output
    if (oldState > threshold) {
      Serial.println("Button Pushed");
      digitalWrite(Pin1, HIGH);
      digitalWrite(Pin2, LOW);
      analogWrite(enablePin, motorSpeed);
    }   // turns the motor on
    startTime = millis();
  }
  oldState = EMGsig;
  if (digitalRead(Pin1 == HIGH)) {
    if (millis() - startTime >= 5000UL) {
      Serial.println("Timer Expired");
      digitalWrite(Pin1, LOW);
      digitalWrite(Pin2, HIGH);
      analogWrite(enablePin, 0);
    }
  }
  Serial.print(EMGsig); Serial.print(" EMG reading, with voltage: "); Serial.println(voltage);
  motorSpeed = analogRead(potPin) / 4;
}

-jim lee

1 Like
3

You forgot to do an auto-format before posting. If you did that you might have noticed that the line "oldState = EMGsig;" is outside the loop() function, either because you are missing a '{' or have an extra '}'.

void loop()
{
  //int sensorState = digitalRead(sensorPin);
  int EMGsig = analogRead(A5);
  float voltage = EMGsig * (5.0 / 1023.0);

  if (EMGsig > threshold) //voltage must be tuned according to sEMG output
  {
    if (oldState > threshold)
    {
      Serial.println("Button Pushed");
      digitalWrite(Pin1, HIGH);
      digitalWrite(Pin2, LOW);
      analogWrite(enablePin, motorSpeed);

    }   // turns the motor on
    startTime = millis();
  }
}
oldState = EMGsig;
if (digitalRead(Pin1 == HIGH))
1 Like
4

The code now uploads, but the motor still doesn't run. The serial monitor verifies that the EMG signal is exceeding the threshold. Any suggestions?

5

Did you leave in this mistake?
if (digitalRead(Pin1 == HIGH))

The paren is in the wrong place:
if (digitalRead(Pin1) == HIGH)

6

made a fix to the if statements and got it working perfectly. here is my code in case anyone can use it in the future`

//const int sensorPin = 2; // the number of the sensor pin
//const int motorPin = 13; // the number of the motor pin

const int Pin1 = 8; // connected to pin 7 on the H-bridge
const int Pin2 = 9; // connected to pin 2 on the H-bridge
const int enablePin = 13; // connected to pin 1 on the H-bridge
const int potPin = A0; // connected to the potentiometer's output

int motorSpeed = 0; // speed of the motor
int threshold = 60; // Move the motor when EMG signal is above this threshold. Remember it ranges 0–1023.
int oldState;

unsigned long startTime;

void setup()
{
Serial.begin(9600);

pinMode(Pin1, OUTPUT);
pinMode(Pin2, OUTPUT);
pinMode(enablePin, OUTPUT);

digitalWrite(enablePin, LOW);

//pinMode(motorPin, OUTPUT);
//pinMode(sensorPin, INPUT);
}
//
void loop()
{
//int sensorState = digitalRead(sensorPin);
int EMGsig = analogRead(A5);
float voltage = EMGsig * (5.0 / 1023.0);

if (EMGsig > threshold) //voltage must be tuned according to sEMG output
{
if (oldState > EMGsig)
{
digitalWrite(Pin1, HIGH);
digitalWrite(Pin2, LOW);
digitalWrite(enablePin, motorSpeed);

  }  
  startTime = millis();
}

oldState = EMGsig;
if (digitalRead(Pin1 == HIGH))
{
if (millis() - startTime >= 5000UL)
{
digitalWrite(Pin1, LOW);
digitalWrite(enablePin, LOW);

}

}

delay(1000);
motorSpeed = analogRead(potPin) / 4;
Serial.print(EMGsig);Serial.print(" EMG Signal; ");Serial.print(voltage); Serial.print(" Voltage; "); Serial.print(motorSpeed); Serial.println(" Motor Speed; ");

}`

7

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