Can’t connect FSR and Servo

Projects General Guidance
1

I’m trying to control my servo using force resistive sensor. But my servo does absolutely nothing. I tried many different wiring schemes but nothing helped. My sensor output is correct, but after some time it starts to look like this: sensor = 1E;
sensor = 1CE etc.
Maybe my servo has not enough energy?
My current wiring:

IMG_0817
IMG_08171170×830 155 KB

My code:

#include <Servo.h>

int sensor = 0;
Servo servo_7;

void setup() {
  pinMode(A0, INPUT);
  servo_7.attach(9, 500, 2500);
  Serial.begin(9600);
}

void loop() {
  sensor = analogRead(A0);
  Serial.print("sensor = ");
  Serial.println(sensor);

  if (sensor != 0) {
    Serial.println("ok");
    servo_7.write(180);
  } else {
    servo_7.write(0);
  }
  delay(1000);
}
2

Servos and motors cannot be powered from the Arduino 5V pin.

Use a separate power supply, and don't forget to connect the grounds.

servo_pwr
servo_pwr1035×538 42.4 KB

3

Do you think your 'sensor' value will ever get '0'? I don't think so. That means your servo always get the command to move to 180 and will never move elswhere.
And what servo are you using? servo.write(180) will create a pulse of 2.5ms in your case. Many digital servos will ignore this completely, because it is out of their specs.

4

What values do you read?

6

I added power supply, but still nothing

7

I changed with to “sensor >= 600”, but this didn’t worked as well.

8

Now this all looks like this.

IMG_0909
IMG_09091512×2016 1.21 MB

IMG_0910
IMG_09103024×4032 2.15 MB

9

Is that a 4 AA battery pack?

10

Yes, 1,5 x 4 = 6W. I thought this would be enough for servo. Am I wrong?

11

No it's perfect.
I would try the servo sweep example to test that the servo works.

12

If the battery pack struggles to start the servo, add a 100uF electrolytic capacitor across VCC and GND at the servo. This will help stabilize the supplied power as the servo starts moving, when power load is greatest.

13

If that is true then you need new batterties.

14

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