I am a beginner when it comes to electronics, coding and things like that (this is practically the first time I have done anything like this), so when building an application that is supposed to vibrate a vibration motor with a strength based on the distance measurement made by the ultrasonic rangefinder, I bumped up with a problem.

The MCP 41010 digital potentiometer seems to let electricity through only when it is given a SPI.transfer(128). Any other number stops the flow of electricity completely.

I have tried some addresses such as 00, 0x00, 0x01 and 0x04 to replace the 0 and the result was the same. With addresses 0x11 and 0x08 the digital potentiometer didn't react at all.

In addition to the code I have here I have tried just copy-pasting some of the tutorials I found from the internet, for example this one Digital Potentiometer not fading LED without really understanding the commands formats thing all that well. With that code I got a vibration that didn't seem to fade in or fade out at all, so the problem remains (I lack a way to properly test that though).

So... what am I doing wrong and how to fix it?

Thank you!

Many tutorials were used when making the code.

#include <SPI.h>

int vcc = 2; // attach pin 2 to vcc
int trig = 3; // attach pin 3 to Trig
int echo = 4; // attach pin 4 to Echo
int gnd = 5; // attach pin 5 to GND

int shortest = 250;
int longest = 12000;

int CS = 10; // for digi pot


void setup() {

  SPI.begin ();
  pinMode (vcc,OUTPUT);
  pinMode (gnd,OUTPUT);
  pinMode (CS, OUTPUT); // for digi pot
  // initialize serial communication:
  Serial.begin(9600);

}

void loop()
{
  digitalWrite(vcc, HIGH);
  // establish variables for duration of the ping,
  // and the distance result in inches and centimeters:
  long duration;
  
  // The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
  pinMode(trig, OUTPUT);
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(5);
  digitalWrite(trig, LOW);
  
  // The same pin is used to read the signal from the PING))): a HIGH
  // pulse whose duration is the time (in microseconds) from the sending
  // of the ping to the reception of its echo off of an object.
  pinMode(echo,INPUT);
  duration = pulseIn(echo, HIGH);

  if (duration > 200 && duration < 220)
  // Limiting out an unwanted, randomly appearing distance measurement
  // made useless by later code though
    {
     Serial.print("Error ");
     Serial.print(duration);
     Serial.print("\n");
    
     return;
    }

   // Compressing the result of the distance measurement into the scale of 0 - 128
  if (duration < shortest) duration = shortest;
  if (duration > longest) duration = longest;
  duration = (1.0f-((float)(duration - shortest) / (float)(longest - shortest))) * 128;
  
  digitalWrite(CS, LOW);
  SPI.transfer(0); // 0x01 and 0x04 seem to "work" too. With 0x11 and 0x08 no voltage goes through
  SPI.transfer(duration); // sending a number from 0 to 128 to the digital potentiometer
  digitalWrite(CS, HIGH);
  
  Serial.print(duration); // printing the result of the measurement and calculations
  Serial.print("\n");

  delay(100);
}

I am a beginner when it comes to electronics, coding and things like that (this is practically the first time I have done anything like this), so when building an application that is supposed to vibrate a vibration motor with a strength based on the distance measurement made by the ultrasonic rangefinder, I bumped up with a problem.

The MCP 41010 digital potentiometer seems to let electricity through only when it is given a SPI.transfer(128). Any other number stops the flow of electricity completely.

I have tried some addresses such as 00, 0x00, 0x01 and 0x04 to replace the 0 and the result was the same. With addresses 0x11 and 0x08 the digital potentiometer didn't react at all.

In addition to the code I have here I have tried just copy-pasting some of the tutorials I found from the internet, for example this one Digital Potentiometer not fading LED without really understanding the commands formats thing all that well. With that code I got a vibration that didn't seem to fade in or fade out at all, so the problem remains (I lack a way to properly test that though).

So... what am I doing wrong and how to fix it?

Thank you!

Many tutorials were used when making the code.

#include <SPI.h>

int vcc = 2; // attach pin 2 to vcc
int trig = 3; // attach pin 3 to Trig
int echo = 4; // attach pin 4 to Echo
int gnd = 5; // attach pin 5 to GND

int shortest = 250;
int longest = 12000;

int CS = 10; // for digi pot


void setup() {

  SPI.begin ();
  pinMode (vcc,OUTPUT);
  pinMode (gnd,OUTPUT);
  pinMode (CS, OUTPUT); // for digi pot
  // initialize serial communication:
  Serial.begin(9600);

}

void loop()
{
  digitalWrite(vcc, HIGH);
  // establish variables for duration of the ping,
  // and the distance result in inches and centimeters:
  long duration;
  
  // The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
  pinMode(trig, OUTPUT);
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(5);
  digitalWrite(trig, LOW);
  
  // The same pin is used to read the signal from the PING))): a HIGH
  // pulse whose duration is the time (in microseconds) from the sending
  // of the ping to the reception of its echo off of an object.
  pinMode(echo,INPUT);
  duration = pulseIn(echo, HIGH);

  if (duration > 200 && duration < 220)
  // Limiting out an unwanted, randomly appearing distance measurement
  // made useless by later code though
    {
     Serial.print("Error ");
     Serial.print(duration);
     Serial.print("\n");
    
     return;
    }

   // Compressing the result of the distance measurement into the scale of 0 - 128
  if (duration < shortest) duration = shortest;
  if (duration > longest) duration = longest;
  duration = (1.0f-((float)(duration - shortest) / (float)(longest - shortest))) * 128;
  
  digitalWrite(CS, LOW);
  SPI.transfer(0); // 0x01 and 0x04 seem to "work" too. With 0x11 and 0x08 no voltage goes through
  SPI.transfer(duration); // sending a number from 0 to 128 to the digital potentiometer
  digitalWrite(CS, HIGH);
  
  Serial.print(duration); // printing the result of the measurement and calculations
  Serial.print("\n");

  delay(100);
}