Woodshop dust collector automated blast gates

Howdy, first time poster!

I'm in the process of setting up a woodshop dust collector and was inspired by this video to automate (a) turning on the dust collector and (b) opening and closing specific blast gates (essentially valves that open certain sections of the ductwork) based on simply powering a tool. In this video, he uses an Arduino Uno R3 and an Adafruit servo shield, along with some RC servos to open the blast gates and an underpowered relay to turn on/off the dust collector. He doesn't go into much detail but he does post his code here.

This will be my first Arduino project so I have a lot to learn about programming it, but figured I could start with his code as a basis. But before I purchase and test different hardware, I want to make sure it will work for my application which is a bit different:

  • My dust collector is bigger - 5hp motor and draws 23a FLA I believe, wired for 240v single phase. I understand this will require a contactor instead of a relay?

  • I don't particularly like his electrical box that stores the current sensor. Is there a better/cheaper way to accomplish this (either a CT or cheap current switch that could simply wrap around a wire without requiring an add-on box at each tool)? Also it would need to work for both 120v and 240v tools.

  • Are the RC servos he's using a good solution? My blast gates will be larger (6" diameter) so the servos will be moving more mass to open/close the sheet metal. If there is a better servo for this kind of application, I'd love to know.

  • Any other advice or things you would caution me against doing? :slight_smile:

  • I live in the USA if that is relevant

Thanks!

I can answer your question about using a CT. You can put one anywhere. BUT, you have to have around ONE wire, not 2 or 3 in a power cable. If you put a CT around a cable with two power conductors, they cancel each other out.

That is the reason for the extra boxes on the cables.

Paul

"Contactor" is just another name for a relay.

Solid-state relays (SSR) are the way to go these days.

I didn't see the video but if it is using butterfly valves (like a gas engine throttle valve) then torque is usually not an issue. The valve is balanced. More air pressure just gives a little more friction.

MorganS:
I didn't see the video but if it is using butterfly valves (like a gas engine throttle valve) then torque is usually not an issue. The valve is balanced. More air pressure just gives a little more friction.

It won't be a butterfly valve. It will be some sort of knife or slide gate valve. The butterfly would collect chip and clog or impair the operation.

MorganS:
"Contactor" is just another name for a relay.

Solid-state relays (SSR) are the way to go these days.

That depends on the size of the dust collector. In the US, a small DC is 120VAC 10A, small-medium 15-18A, medium 240VAC 12-15A. medium-large 240VAC 15-18A.

The motors get big on woodworking tools. The professional motor starters for these tools are contactors.

ryanjg117,

I was wondering how your Dust Collection system worked out, did you use CT’s I am doing the same project. I am using AC712 for low current items. I would love to see the sketch used with CT’s to drive the blast servos.

Lane

I’m in the process of setting up a woodshop dust collector and was inspired by this video to automate (a) turning on the dust collector and (b) opening and closing specific blast gates (essentially valves that open certain sections of the ductwork) based on simply powering a tool.

Sounds like an interesting project! Good luck :slight_smile:

This will be my first Arduino project so I have a lot to learn about programming it, but figured I could start with his code as a basis.

Hmmm…
If you use someone else’s code then you won’t know what it does or why it does it, and most importantly, when it doesn’t work the way you want you won’t know where to start with modifying it. You’ve got to learn C and C++ anyway, may as well learn by starting simple and writing your own code from scratch, in my opinion anyway.

Have you considered using a solenoid to pull the
valve open? Or a rack and pineon to slide it open?
Herb

herbschwarz:
Have you considered using a solenoid to pull the
valve open? Or a rack and pineon to slide it open?
Herb

Solenoids typically have a short throw compared to the travel required for the gate to open and close. For example, a solenoid with 3/4" travel to open a 4" slide gate needs a 12:1 ratio. That becomes a lot of force to be put out by the solenoid which increases the size and power (current) requirement. Better to use a rack and pinion, ball screw drive, or pneumatic for slide gates or direct drive for swing gate.

This was my first arduino project and the learning curve is huge! I Completed this project today.
I made the mounts and servo arms from 1/4" plywood cut with a jigsaw (I wasn’t allowed to buy the laser cutter!)
I used a 4mm flanged bearing to mount the arms to the 4" blast gates for a more precise control.
WireMould makes a device box large enough to hold the sensors and a single 15 amp 120 volt receptacle
I mounted the Arduino with the servo shield inside an old junction box I had laying around.
The arduino and the servo shield have their own power supplies.
Trying to find a 2hp contactor with 5vdc coils is a bear, so I used a relay and a Packard C230B 2 Pole 30 Amp Contactor with 120 Voltage Coil. It was reasonably cheap…$20.00 Canadian.
I used b2955 4" Blast gates from BusyBee Tools.
I used bigger servos (DS3218mg) The DS321mg servos are good to move 20kg. of force.
The code is the same as Bob did, after cleaning it up to work with 3 tools and 3 servos.

ryanjg117:

  • Are the RC servos he's using a good solution? My blast gates will be larger (6" diameter) so the servos will be moving more mass to open/close the sheet metal. If there is a better servo for this kind of application, I'd love to know.

You probably need a bigger servo then.
Check the weight of your valves, any other resistance involved, and use that to calculate the torque needed. If the valve is really heavy you may place a counterweight on the other side so the servo is at the balance point. Then you only have to overcome the inertia (plus of course some for the imperfections the real world imposes onto everything).

MorganS:
Solid-state relays (SSR) are the way to go these days.

The other day I looked for 10-15A SSRs on Digikey, and found they cost more than 10x a regular relay with the same rating (also as posted on Digikey; made-in-China relays are of course even cheaper). That was pretty prohibitive.

DaleP650:
This was my first arduino project and the learning curve is huge! I Completed this project today.
I made the mounts and servo arms from 1/4" plywood cut with a jigsaw (I wasn't allowed to buy the laser cutter!)
I used a 4mm flanged bearing to mount the arms to the 4" blast gates for a more precise control.
WireMould makes a device box large enough to hold the sensors and a single 15 amp 120 volt receptacle
I mounted the Arduino with the servo shield inside an old junction box I had laying around.
The arduino and the servo shield have their own power supplies.
Trying to find a 2hp contactor with 5vdc coils is a bear, so I used a relay and a Packard C230B 2 Pole 30 Amp Contactor with 120 Voltage Coil. It was reasonably cheap...$20.00 Canadian.
I used b2955 4" Blast gates from BusyBee Tools.
I used bigger servos (DS3218mg) The DS321mg servos are good to move 20kg. of force.
The code is the same as Bob did, after cleaning it up to work with 3 tools and 3 servos.

What kind of relay did you use to control the Packard C230B?

I just bought the parts. Did you have to modify the code much to make it work for you?