Arduino Uno: Potentiometer (6)

Arduino Uno with a Potentiometer or Variable resistor.

 

Potentiometer can sweep its output between two voltages it is supplied.

Build circuit

• Connect 5V on the Arduino to PWR Rail on the breadboard
• Connect GND Rail to J29
• Connect 5V on PWR Rail to J28

• Connect the Red wire from POT to H28
• Connect Black wire from POT to I29

• Connect the Blue wire from POT to A0 on the Arduino.

• Modify your sketch to ass the following variable.

• Read value on pin A0 by using analogRead.
• Serial.println the value on A0
• Change delay to 50 ms.

• Compile and Upload
• Start Serial Monitor
• LEDs should be blinkling fast.

 

What does the value mean/represent?

• Value is digital (integer=whole number) equivalent of average value
• When the voltage is 0.0V we see "0"
• When the voltage is 5.0V, wee see "1023"

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What resolution?

• 10-bit conversion has 2 power of 10 (0 to 1023) possible values
• Resolution is:

• What is the voltage ooutput of the potentiometer if value is 689?

Modify the sketch to calculate the voltage based on the analogRead value and print to the screen

• Will need to create a new variable (float) and use some math
• Printing more than two items to the screen, use....

       ☆ Serial.print("      ")            // to print to same line

       ☆ Serial.print("\t    ")            // to create tab

       ☆ Serial.println("   ")            // to create a new line

• Let's look at the code change

• Float because its not a whole number

• Verify and Upload
• Launch Serial Monitor
• Turn potentiometer until you see 689 and verify same value we calculated.

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What would you have to do to use the sensorValue to control the delay of LED Blink pattern?

• Replace time in delay command with sensorValue
• Let's look at the code changes

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One more step....

• Modify the sketch so we can use our LED Visual Display instead of the serial monitor to know what the sensor value / voltage is 
• Use a series of if statements to turn LEDs for different values.

• Comment out previous digitalWrite commands.

• Add the following "if statements" to your viod loop.

• Compile and Upload.
• Verify LED Display is working by comparing with Serial Monitor and Potentiometer reading.