if any circuit emulator programmers pass by.. .

I'd love to see the next level of evolution....

How I hear you ask! Let's interface the phone sensors :) we could feed in analog values like accelerometer or compass and other similar sensors...

Then in circuit emulation feed the speaker into a circuit to create fuzz , feed in light sensor as an ldr, detecting light etc, but have it all emulated as a circuit doing the real thing!

Creating your own circuits to interact with phone sensors, transitors causing clipping if not correctly biased so without even being near a breadboard you get to experience the real thing emulated :)

So you want the sensors on your phone to be used to provide "live data" for simulations of the more primitive sensors that are typically connected to arduinos? "My phone has a noise-canceling direction-sensing automatic-gain-controlled micromachined silicon microphone, therefore my simulator can surely produce ADC results that are similar to what someone would get with the usual one-transistor electret mic setup on an arduino?"

That seems like a pretty good idea.

Well...

An Arduino could be emulated to a degree...

For example, take a flip flop circuit... it could be designed several ways either transistors, an IC gate, 555 etc, you desihn the circuit and you run it, now in that same circuit speed it up a little add a microphone amplify the signal give it some feedback and when you're done designing it hardware wise you can then use the loudspeaker.

An LDR can spit out a simulated light level based on real light levels, have the led light come on or screen come on whe it's dark.

How about a component than when given a high signal will connect to a webserver and send a request, It could be used to develop some new Intresting phone applications using nothing more than emulated electronic circuits instead of writing pure code...

Create a clap circuit, emulate it and clap at your phone..

I connect a lot of stuff with my phone using bluetooth, wifi and usb , failed at microphone plug in communication too much busy to implement fft stuff and analyse it. Its the future everything is going to interact with you using you phone as the medium.

Some simulators allow you to inject or export data from WAV files. Not just audio, but any sampled data. I don't see that as much different than using a phone to provide those data streams, so I guess it would work OK.

Although westfw's point is a solid one -- you don't want to use your phone to emulate a discrete sensor device if that sensor's behavior is important to the circuit's functionality. The data produced by sensors behind conditioning circuits and DSP will often by far removed from a simple discrete device. Much better, if you're going to combine real hardware with simulated hardware, would be to use the actual sensors your virtual circuit would use. If that's still a phone, well, so be it.

Nonetheless, if the point of the design is to react in ways that can be met be either source, why not? ...Except, perhaps, that simulation usually lends itself to an "all in the box" method of development, whereby having any external hardware at all is much less productive than generating equivalent sample data via software.