help with a sketch

hi all,im building a magnetic loop antenna,ive got a stepper motor driving the tuning capacitor,using a uno and a driver shield,ive modded the stepper test sketch to drive the motor but what i need to do is monitor the voltage from an rf bridge so the motor stops when it gets below a certain voltage,can i use an analogue input and any idea of the code to do this?,cheers Paul m3-vuv

paul_larner: can i use an analogue input

Without a schematic the answer is solid "maybe".

any idea of the code to do this?

The best strategy for getting help with code is for you to write some code, post the code, apply the advice, repeat until finished.

you dont need a schematic!,i want to monitor a voltage and have it stop the program running when the voltage drops below a certain point!!

if (analogRead (somePin) < someThreshold) {
  stopMotor();
}

but im new to this and dont know where to start!

The IDE is packed with worked examples

You can start by not yelling at everyone.

Youtube has excellent beginner tutorials. It's how I learned.

paul_larner: you dont need a schematic!

In that case give the output specification of your device. Don't come crying because you try to measure a signal in the range of a few microVolts and it does not work or if the output impedance of your circuit is in the megaOhm range and it does not work.

Just to name a few