Hi again,
If we omit potential false triggering for the moment being, the scenario would follow these lines :
) Current sensor starts the Delay-Off circuit
) Delay-Off circuit starts Delay-On circuit
) Delay-On circuit triggers the Triac on time out, vacuum starts.
) Current sensor "sees" that the tool is no longer used therefore it stops the Delay-Off circuit
) Delay-Off circuits times out, shut itself down along with the Delay-On circuit
The triac will be exclusively used to start the vacuum or any other controlled load. The main tool is not controlled by any electronic component, it is strictly standalone.
The relay approach is not really out of question, but I'm considering it as my plan B, as I actually had in mind to make it as compact as possible. In fact, I have no environment restriction as such, so the box could be the size of of shoe box and tha't would be just fine. So the dimensions of the finished product is only a personnal goal or taste.
For the snubber circuit, I was aware of it when I did my researches on Triacs and other thingies. I have some special resin and epoxy, normally used for garage floors, which is rock solid, so I figured to put the X-Type capacitor and the Resistor in a little mold, with 2 pins or connectors of some sort, so that the final snubber can be exchanged, replaced in a modular way. So if I need to control a load which is way less or more inductive, or any other characteristic impacting the snubber specs, I could simply swap the snubber as easily as changing a car fuse.
Before starting this project, I knew I'd face a lot of new things, and that's the beauty of it. I'm not in an absolute need for that "current load sensing master/slave" thingie, or whatever you want to call it, I simply decided to give it a try, exploring new avenues, learning more about electronics.
I could go the easy way, using relays to simplify my life and the overall construction, but that would defeat the purpose of the whole thing, the challenge !
If I opt for the relays, I'm pretty sure the whole thing would be completed rather quickly, and that's OK. On the other hand, if I make it relayless, I'll have a better feeling about it.
Overall, this is strictly for a hobby, so time and efforts are not really a concern. I don't give up easily, believe me !
Keep in mind that I'm not ignoring the relay approach, I simply consider it as my plan B.
Note: I've been successful at "transistorizing" the switch S1 on the Delay-Off circuit. It might not be much for some of the readers, but for me, that's one step ahead.
Best regards.