A flush-actuated turbine is problematic. You need a lot of velocity to wash the crap off the walls. Turbine in the flow will extract energy and slow the flow down.
Better put the turbine to the inlet of the tank. You can take all the energy from the water pressure in the pipes, the tank doesn’t care about how fast the water flows in. So pressure->speed->electricity.
There are showerheads that use this embedded generator with LEDs mechanism.
But we’d need some sensor, as the LEDs may need more power than the energy in the water flow, especially if the toilet is not in a high duty. May be alleviated by a sensor.
Could be hooked to some telemetry and use the frenzy red when imminent diarrhea is detected.
