# Arduino Uno with a Pot to control voltage

Hello, I am new to the Arduino so bear with me. I am trying to vary voltage to a a device. I need the voltage to go from 0-8 volts. so my Question is: how can I hook up the POT,code the Arduino, and hook up the device I have got a good idea from watching this Vid : http://www.youtube.com/watch?v=FKj9jJgj8Pc However, unlike the Servo my device does not come with Arduino code to make my life easier.

what I have so far is this: I have connected the POT to the 5V, Ground, and control pin # 2 ( analog ). My output device is simply connected to Ground and pin #13 ( digital ).

my code is not doing what it needs to ( i.e vary the voltage ) all its doing is going from 0 V straight to 8 V.

can anyone suggest a way to make the voltage vary from 0-8V using the POT .. Thank you

int potPin1 = 2; int valve = 13; int val1 = 0;

void setup() { pinMode(valve, OUTPUT); }

void loop() { val1 = analogRead(potPin1); val1 = map(val1,0,1023,0,8); digitalWrite(valve, val1); // turn the ledPin on delay(0); // stop the program for some time

}

thats pretty much how i have my POT connected .. but it does not show I can vary the voltage from 0-8V using the POT

Where are you getting the "8V"?

I have connected the POT to the 5V, Ground, and control pin # 2 ( analog ).

...which will vary the voltage from 0 volts to 5 volts.

i have connected the Arduino ( from Vin and ground pins ) into a DC power supply.

Are you wanting to vary the Arduino OUTPUT voltage from 0 volts to 8 volts?

yes Exactly !

You need analogWrite.

You need analogWrite

Nope. The output is either 0 volts or 5 volts. There is nothing in between.

yes Exactly !

In which case, you are going to have to provide a description of the hardware.

10 K pot, connected in the manner described above, a Valve that operates from 2.5-8 V connected in the manner described above

As the Arduino pins supply 5 volts and your valve requires 8 volts I would suggest using the Arduino to control a transistor supplying the 8 volts to the valve.

The Arduino doesn't have a built-in D/A (Digital to Analog) converter. it simulates an Analog output with Pulse Width Modulation: turning on a 5V signal only part of the time.