So this could be done but would be complicated.
In short, you have power coming into your range hood, and it goes to your rotary control, and then onto the light.
Power from Breaker Box------->Current Rotary Control----->Light bulbYou'd need to somehow insert a dimmer module somewhere that Indigo could control. If you were to insert the module in front of your local rotary switch,
Power from Breaker Box----->Indigo Controlled Dimmer Module---->Current Rotary Control----->Light Bulbif the Indigo module was turned off, then no matter what you do with the rotary control, nothing will happen. Likewise, if the Indigo module was turned on, but the rotary switch was off, Indigo won't be able to turn it on.
Likewise, if you insert the module between your rotary control and the light,
Power From Breaker Box---->Current Rotary Control----->Indigo Controlled Dimmer Module----->Light Bulbwith the rotary control turned off, there is no power for the dimmer to operate, not to mention that dimmer modules don't work with dimmers in his setup. You'll basically cause the dimmer module to burn up wired up this way.
Don't Do This!!The only real option I can think of would be to wire in one of these:
https://www.smarthome.com/insteon-2442- ... odule.htmlThis module would connect directly to your power source coming into the hood, and directly to the light.
Power from Breaker Box----->Insteon 2422-222----->Light BulbThis module could be controlled via Indigo, but you'd also need an Insteon Modem to make that work. Those little black and yellow wires could then be connected to a new switch that would replace your rotary one... basically a push button type of switch. Press it once, and the light will ramp up to a certain brightness... press it again, and it would dim all the way down to off. Regardless of the status of the dimmer (on, off, dimmed) both the local control and Indigo could change it from whatever sate it is in, to the state you want it to be in.
The real problem I foresee is managing to find the right kind of switch to replace your rotary one that will fit into the same space as your present switch, and have the electrical characteristics that you need to make the dimmer work locally. Not impossible, but not necessarily for the faint at heart.
Good Luck!