Small motor with TA7291P

Using Arduino Motors, Mechanics, Power and CNC
#1

Hey, hope ive chosen the correct form for my post, if not i apologise.

i am trying to control a small motor (from a hand fan) that normally runs from 2AA batteries, i am using a Toshiba ta7291p bridge driver with my uno trying to control the motor. What is happening when i enter the control to speed up/turn on the fan, the motor makes a very faint hight pitched sound but no movement, at times the chip heats up as well.
From what i understand on the datasheet the max amps its takes is 2, wondering maybe my amps are too high or maybe voltage too low ?
ive measured the fan to battery’s as 3 volt with round .6 amp, not too familiar with multi-meters so my settings could be off by loads ?
Be great if somebody could help, maybe its not possible with this motor if not any ideas on which one would be best (just using it for a fan) ?
here image of the set up and sketch

2592×1728 877 KB

2658×1110 254 KB 

#include <string.h>

// Motor preparation. Motor driver using the TA7291.
int Pwm_pin = 3; // Connect the fourth of TA7291 to Digital3 number of arduino.
int MotorA_pin = 7; // Connect the 5th of TA7291 to Digital7 number of arduino.
int MotorB_pin = 8; // Connect the sixth of TA7291 in Digital8 number of arduino.
int motorpwm_val = 0; //the rotational force of the motor;  0-255.


char serialmessage [256]; // put the string to receive the serial communication array. Until the time being 256 characters.
char * splitserial [10]; // split array to store the string. For now up to eleven.


void setup () {
  Serial.begin (115200);  

  // Set of motor pin
  pinMode (MotorA_pin, OUTPUT); 
  pinMode (MotorB_pin, OUTPUT);
  digitalWrite (MotorA_pin, HIGH); 
  digitalWrite (MotorB_pin, LOW);
  analogWrite (Pwm_pin, 250); 
}


void loop () {

      
Serial.print("motorpwm_val=");
Serial.println(motorpwm_val);      
      

 if (Serial.available ()) {
    delay (10); 
    serial_to_char ();
    splitchar (serialmessage, ",", splitserial); 
    
    if (splitserial [0] = "motor") {
      motorpwm_val = atoi(splitserial[1]);
      Serial.print ("motorpwm_val =");
      Serial.println (motorpwm_val);
      analogWrite (Pwm_pin, motorpwm_val);
    }
  }
  if(Serial.available()){
    delay(800);
    serial_to_char();
    splitchar(serialmessage,",",splitserial);
    
    if(splitserial[0] = "motor"){
      motorpwm_val = atoi(splitserial[1]);
      Serial.print("motorpwm_val=");
      Serial.println(motorpwm_val);
      analogWrite(Pwm_pin,motorpwm_val);
    }
  }
  

}

void serial_to_char () {
  memset (serialmessage, '\0', sizeof (serialmessage));
  for (int i = 0; Serial.available (); i ++) {
    serialmessage [i] = Serial.read (); 
  }
}
// Char string to split.
void splitchar( char *str, const char *delim, char *split[] ) {
    char *splitpart;
    splitpart = strtok( str, delim );
    for( int i = 0;splitpart != NULL && i < 10 ;i++) {
        split[i] = splitpart;
        splitpart = strtok( NULL, delim );
    }
}

Thanks again, any help would be appreciated, just starting with Arduino !

#2

Firstly that chip drops about 2V internally, so a 3V motor will need a 5V supply.

The absolute maximum rating is 1.0A for the P package and 0.4A for the other packages.
That's the continuous rating at 25C, in practice it will be hotter and you must de-rate
accordingly (the abs max the peak rating isn't relevant here).

Remember that you never take a device to its absolute max, you keep well within it,
so I'd rate the chip at more like 0.6A or 0.3A continuous (depending on package type -
I don't know whether you have the high power package or not - you will need a heatsink
of course)

#3

Thank you, i am just trying to power a fan for about 10 min, so i need to up my battery amount and attach a heatsink to the chip, i thought that the chip was getting its power from the arduino though and that the batterys power would go directly to the motor ?
Thank you again, still very new to all this !

#4

Motor drivers normaly get a motor supply and a logic supply. Sometimes the logic
inputs don't need a separate supply. the datasheet is the place to look for information.

#5