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Basic Electronics » Turn Vac on when tool turns on

April 05, 2016
by Ralphxyz
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As I built my shop and started doing more wood work projects the need to have a vacuum cleaner and power tool running at the same time became very apparent.

Now I have this i-socket off ebay (Rockler) and it is fantastic. I just got a Leigh dovetail jig and it has a sled to move the router on with a vacuum attachment using the i-socket with my router was amazing.

The vacuum turns on automatically when the router is turned on and stays on for a few seconds after the router is turned off to make sure and get all of the debris.

So I need another one. How would I make one?

I imagine I would start with a current sense device hooked to a micro hooked to a relay.

Any thoughts?

Ralph

April 06, 2016
by BobaMosfet
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Ralphxyz-

As you're dealing with AC, I'd expect to take that to logic level DC for any control circuitry (using caps and a full-wave-bridge). Instead of relays, I'd use a transistor on the secondary. I agree with current-sense on the primary (tool) outlet. I'd use a Zero-Cross-Detect circuit to determine when to turn the secondary (vaccum) outlet on and a thermister to limit inrush current. A capacitor and a few extra components could be used to maintain power on a transistor for the secondary for 5-10 seconds afterwards.

No micro-controller needed, and I'd use opto-isolators to isolate mains power from the logic.

BM

April 07, 2016
by BobaMosfet
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Ralphxyz,

Thinking about it, you can also eliminate the thermistor, since the ZCD will prevent high-current when vaccuum turned on.

BM

April 08, 2016
by Ralphxyz
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Thanks BM, I was thinking of using a ACS712, since I have a bunch on of them hand, that is why I included a micro.

But I am open, to any readily available, cheap, components, considering the i-socket cost $39.99.

I might finally get around to making an actual printed circuit board.

I am amazed what a pleasure it is working with the i-socket.

April 11, 2016
by BobaMosfet
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Ralphxyz-

I can appreciate how convenient that is. I have done a lot of woodworking, and know how much sawdust gets generated from routers and tablesaws. It's a brilliant idea. To be honest, I'm probably going to make a circuit for it and the PCB as well so it will fit into a 2-gang electrical box.

If I do, I'll post that information here, for all.

BM

April 11, 2016
by BobaMosfet
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Ralphxyz-

The ACS712 is a nice little sensor, saves you from creating a sensor out of basic parts (inductor, FWB, caps, etc).

BM

April 12, 2016
by Ralphxyz
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Thanks BM.

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