User Interface other than serial monitor

I have successfully made a number of projects using the Nano. The most recent is an automotive ignition coil tester. But to change the parameters used in this and other programs I have used the Serial Monitor. Is there another way to do this. Can I write a program where I can make GUI on the host computer and communicate my variables to the Nano via the host? If you could point me in the right direction I would appreciate it, Thanks, Mike

I have used the Processing language to create GUI on my PC for my Arduino projects. Communication between the Arduino and PC are via a serial port.

I briefly looked over the Processing web site. Looks like it is free, which is in my ball park. Tell me, If I had a program such as Blink an LED, how could I control the on and off times. Are there slide bars, scroll bars or other such controls to do the job? Does the Processing website have some examples to look at? WHat type of controls have you used? Thanks Mike

I just found a nice Processing book and ordered it. Hopefully I will fins what I need in it. Thanks Mike

I usually make my own controls (buttons, text boxes) from scratch. There are several libraries for making a GUI.
ControlP5 and G4P are two of them. There is example code in the contributed library examples.

Hello Mike.

I've been using an Android phone as my control pad. It communicates with the Arduino via Bluetooth.

The Arduino sees the Bluetooth as a serial port, either hardware serial or software serial. No different to using the IDE monitor.

On the phone side, I write an app using MIT App Inventor. That involved a significant learning curve, but well worth it to me.

Alternatively to writing a custom app, you can use an off the shelf Bluetooth Serial Monitor app (several available). These perform just like the IDE monitor and takes minimal effort.