Pilot the Led with a slider?

Hello again,
I was making some tries on my blade and led, and found out that if I attach a Trimmer / potentiometer to manage the light, it give a nice opening and closing effect, very similar to the led stripes effect, but ofc, without the led stripes and with a single led.

So my idea was to put a "slider" trimmer that also has a function to 'turn off' the whole circuit. Where can i find something like that? does it have a different name? Or should I add some sort of transistor to the slider in order to have what I want?

You can't have the slider kill the circuit. Because the slider is unable to control the circuit. The Leds can be driven from a range of voltages. The rest of the circuitry in a lightsaber can not. Unless you're making a stunt saber that only has lights. This can be done however by adding a wire from the slider/potentiometer to something that can detect whether there is voltage or not. I would use a microcontrolelr. But you can probably do this with a transistor if you look up a switch circuit. So I guess you're right about the transistor being plausible.

You can use the dimmer along with a latching style switch. The switch to turn the saber on/off, and the dimmer to get the extend/retract effect.

Or you could get any of the sound boards from TCSS. They all do that effect natively, and give you sound as well.