My first-year engineering group is designing an automatic shut off oven system. We will integrate smoke detector systems inside the oven. Details about that don't matter. Smoke detectors work on a trip wire type alarm. Alpha particles are emitted from a small source of Americium, the alpha particles ionize the air and complete a circuit. When smoke enters the system, the ionization doesn't occur and the circuit is broken and the alarm is triggered. We will be using just the ionization system, but not the built in circuit with the smoke detector, because we need to incorporate it into a larger system, and modifying the existing circuitry would be almost impossible. Disregard the ionization system and replace it with a simple switch - on or off. And replace the entire alarm function with lighting a simple LED. We can modify the circuit from there, I just need a circuit, preferably a schematic too, that will light an LED once a connection is broken, or a switch is turned off. Thank you for taking the time to read this!