Dust Gate Project

@garry42

In my workshop I have dust gates placed near the main dust pipe with runs off this to my various machines hence my plans to automate the opening of the gates via wireless signal mechanism, when I get around to it.  In the meanwhile I follow along others efforts to see what they come up with.

One thing I don't really understand with your design is that you seem to have all your gates open, meaning you then need to close those you don't need, rather than having them all closed and then only opening the one you need.  When opening the one you need then it would also be trivial to automatically delay the dust collection vacuum switch on until the gate is fully open. 

The very small delay twix opening the gate and the vacuum on would probably not be much longer than pressing the gate open switch and the pressing the machine on switch and steading the wood to feed into the machine.  (assuming you go for a separate gate switch and not a machine on current sensor switch)  

I do see that having all gates open would mean you could 'google on' your vacuum, but with all the gates open the dust collection at the machine in use must be trivial until all the other gates are closed so I don't see what you are gaining by this approach.  However maybe you find the dust suck is adequate even if all the gates are open ??

I am not sure that I said that all the gates were open. Perhaps more detail is required.

I am using the panel saw and the gate is open. I finish and I leave the shop. I return, it may be an hour, a day, a few days or even a year later.  I start a machine and I want that gate open and all others closed, but I cannot remember which gate is open. When I hit a button I get the system to send a signal to all gates except the local gate.

On each of the other gates the motor is integrated as to its position and this is why I chose stepper motors as servos do not report position, as far as I know. If closed do nothing. If open then close. Assuming it takes 5 seconds to close the gate, wait 7 seconds. Check the position of the motor. If it is higher than 0 signal an alarm to indicate the gate is open which indicates some matter stopping the gate from closing completely. The alarm could be a sound, but a light is a better idea. A single LCD display which shows the number, but this would require individual coding of each gate to indicate which gate is open.

On the local machine check if the gate is open, if so do nothing. If closed then open the gate and wait 10 seconds. If not fully open then sound an alarm.

This is very similar to the commercial system that operates on machine on/off and also checks to ensure there is always a gate open, gate 1, when a machine is turned off. It also has an option for the collector. To have gates at all machines in my shop would cost about $3,000, and I already have the manual gates.

To get super fancy and use a number pad I could have another gate on the port at the collector. Setup the gates on each port of the extractor in numerical sequence, 1-5 on line 1, 6-10 on 2, and 11-15 on 3. Press the number of the machine and close the port gates and open one, and check. This would seem to give the best dust flow and reduce the possibility of dust getting caught. There could even be an option to open all gates, although not sure why this would be useful.

And if I really get lazy there could be an LED on the open gate, so if the light is on I do not have to open the gate at all. Not sure I like this idea of wasting battery, but it could be an idea if I power all the gates as I turn off power at the switch board to all machines at the end of a session

The unit should be the same regardless of the machine so one set of code and they can be moved between machines should there be an addition or a gate failure. The unit could be battery powered as most of the time there will be no gate movement and it will only be the computer hardware drawing power. One battery should last a year, I guess. Change the smoke detectors and change the dust gates.

All this should operate on a few volts so there is no electrical danger. The only wiring should be from the switch point to the back of the machine where the gate is located, making it neat and flexible within the confines of the shop

@garry42

Your design goals have been fairly clear from the beginning, it’s just that they are a little surprising. Let’s just say that, as currently envisioned, you have chosen a very ambitious first project. But, you did ask for advice. 😋 😋 😋 

For starters, your decision to keep the dust collector on/off status (via Google or whatever) separate from the blast gate open/close status makes the program logic more complicated. Because, as you probably realize, you need to have at least one gate open whenever the DC might be turned on to keep it from potentially overheating.

Even if you are a retired programmer, actively managing each gate’s open/close status is going to be more complicated. Whether you maintain a database, or proactively query each device, it will be a lot more code than a simple “when (any) gate opens, then turn on collector”. No matter how you choose to implement it, the system has to know the status of every gate in the system regardless of whether they are operated manually or by motor. Especially for the first iteration, simpler is better, and making the default state closed is as simple as it gets. But that only works if the DC is turned off automatically when the last gate closes.

Start out gradually. Not every gate needs to be motorized. A simple $2 switch can be easily retrofitted to existing gates to signal when a gate is manually opened or closed. And of course, inaccessible gates can be motorized and activated by either a toggle switch or perhaps (eventually) current sensing when the machine is turned on.

The best reason to approach the problem this way is that it is more easily addressed in stages. Which, when you are learning, is likely to be a lot more satisfying and much less frustrating.

I do strongly suggest, that before you do anything else, get one working prototype of a motorized blast gate. That will determine the type of motor and the coding requirements. Then, run it for a while via a switch connected to an Arduino (or your controller of choice) on one of your machines. That will help you determine the longer term reliability of the mechanical and basic electronic design.

Once you are satisfied, any additional coding to manage multiple inputs will be straightforward.

Sorry if I sound so pessimistic, but I really think your initial approach would be a lot more frustrating than fun.