Hi there,
Does anyone know if the TB9051FTG Carrier will function with a 3.3V logic Arduino?
According to the TB9051FTG datasheet it should work with 3.3V input signals.
The minimum VIH is 1.75V, the 3.3V Arduino will output signals close to higher than that.
The TB9051FTG needs to be powered with 4.5V (or more).
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Thank you! I’m very new to motor drivers so I’m not sure how to connect it to the microcontroller. Do you know what pins I need to connect to on the driver and what pins I don’t? I have a simple brushed motor that I want to drive with a PWM signal from the analogWrite() function on Arduino IDE and a 5V supply for the motor. I was planning on also using the 5V for the VCC pin.
The link you posted documents this. What are the motor specifications? Post your preliminary schematic showing how you think it should be connected.
Hi @gilshultz ,
Here is a preliminary schematic I made that I plan to implement for testing:
This is the code that I wrote to see the motor change speed in a loop:
int pwm1 = 10;
int pwm2 = 11;
void setup() {
// put your setup code here, to run once:
pinMode(pwm1, OUTPUT);
pinMode(pwm2, OUTPUT);
analogWrite(pwm2, 0);
}
void loop() {
// put your main code here, to run repeatedly:
analogWrite(pwm1, 200);
delay(5000);
analogWrite(pwm1, 120);
delay(5000);
}
Does this make sense? 5V is coming from a benchtop power supply. The system is expected to draw 2A
The system will draw 2A, how did you determine that and what is the required current for the motor. Both running and LR if available.
@gilshultz The pump I am using I got from Amazon and there were no real specs given: https://www.amazon.com/gp/aw/d/B0BJVTB67H/ref=ya_aw_od_pi?ie=UTF8&psc=1
I tested the current draw at the nominal voltage of the motor (4.5V) and it was around 2A. Just an hour ago, I ended up testing the circuit I sent you with the motor driver and it worked but I got about 1.5A draw instead of the 2 that I was expecting for analogWrite(pin, 255). It seemed like the motor was spinning less fast. Could this be due to the PWM frequency (ie not high enough)? Maybe it’s because I’m running it off 5V instead of 4.5V (I feel like this is unlikely)?
Thank you for your help
That would point to the voltage dropping with that current draw. Measure the voltage while the motor is running.
Not really, the DC motor is a current device and its performance is dependent on many factors, one of the biggies is watts. If the power is switched on and off (duty cycle) 50% the motor will only have half of the wattage so its performance will degrade accordingly. Many motors are designed for this and it does no damage but gives you a way of controlling it. If the voltage is fixed you can also use amperage as amps * Volts = watts. Changing your frequency will have little effect but changing the duty cycle will have a big impact. Play with it and find out first hand how it works. For frequency adjustment you need an AC motor.
From my understanding though, at analogWrite(255) (100 percent duty cycle) it should have the same output as a direct power supply so I’m confused as to why I’m not seeing that.
Measure the voltage at the power supply and motor when running. Without that information I cannot help any further, Good Luck!
@gilshultz I measured the voltage and the current at the motor using a more accurate setup and it was closer to 1.6A and 5V. I then tested it again using the motor driver and the output was 5V and 1.4A. So not as big of a difference but still noticeable. I also put an oscilloscope to the output of the driver and it was a pretty noisy signal which is not to be unexpected. Any ideas?
That sounds reasonable, without knowing the motor specifics nothing appears wrong. Brushed motors do not run clean or are they steady state on current. At this point I am assuming it is a series motor.
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