I would like to create some simple sensors like the sr04
i saw the sr04.cpp and sr04.h files.
Yes, SR04 is already implemented.
For sensors like humidity sensors, I think you can just use variable resistors.
To add some graphical representation you should subclass Variable resistor and reimplement Paint() function.
But it depends on how you want it to work, maybe you want to set humidity percentage instead of the resistance directly.
For this, have a look at other resistive sensors like LDR.
For IR proximity sensor, depends on how you want it to work. As far as I know, it is just an on/off digital signal, so maybe you just want to subclass "Fixed Volt" component.
For the microphone, if you want to get audio from the computer, currently there is no audio input in simulide.
You should implement the audio part.
What I would do:
Start with the simplest one, perhaps the humidity sensor.
Determine exactly what you want it to do.
Have a look at LDR component, copy it, renaming files and classes and reimplement whatever you need.
If you get into problems or don't know how to do something, don't hesitate to ask.