DIY Dust Collection Automation: Smart Blast Gates with Home Assistant
2024-11-08 | By Zach Hipps
License: General Public License
I have a problem. Sawdust. It is everywhere. That’s why I recently used some off-the-shelf smart switches to automate my dust collection system. When I turn on a tool, my dust collector also turns on! This is a great start but I'm still missing something. I need to install some PVC pipe around the different areas around my shop, and I need blast gates to control the flow of air. But ordinary blast gates won’t do. No, I need automated blast gates!
The main issue with ordinary blast gates is that they require manual operation. I would have to remember to pull them open and push them closed every time I make a cut. Imagine that! Walking all over the shop, pushing and pulling, there’s no way I’ll remember to do that every time. And I value my health and I want clear lungs so let’s see if I can avoid the task of remembering altogether and protect my lungs. I have three main zones in my shop where dust will be collected. They are the table saw, the miter saw workbench (which also has other tools that need dust collection), and the CNC router which is one of the biggest dust culprits in my shop.
I will start by running 4” diameter PVC pipes from my dust collector to the three tool zones. I want to avoid using flexible hoses because the ridges reduce airflow quite a bit, and we don’t want that. I need to find a good spot and the space under my lumber rack is perfect for hiding a long-run pipe. Each zone gets a “Y” splitter off the main pipe.
As I set up the three zones, I'm starting to consider adding a little floor sweep zone to suck up debris when I sweep the shop. It won’t take that much extra effort, so it goes on the ground near the middle of my shop. Awesome! Scope creep badge has been earned for this project!
Now I need to test how much of a difference blast gates will make with my system. I’ll put a small pile of sawdust in front of the sweeper zone (the furthest port) and leave all the other ports open. When I turn on the dust collector, almost nothing happens. I could feel the air a little with my hand, but it didn’t do anything to the sawdust. To mimic what it would be like with the blast gates installed, I use some small offcuts of plywood to cover the three other ports. Wow, what a difference! I didn't even have to sweep the dust in it, and it illustrates how important blast gates really are.
The manual blast gate I have is a linear-style blast gate which means to pull it back and forth. If I want to build something that does the same thing, I will use either a linear actuator or a pneumatic cylinder, as I've done in previous projects. The problem with using a pneumatic cylinder is that I don’t want to run an air supply to each blast gate in addition to electrical power for the solenoid valves. If I’m going to need electrical power at each gate anyway, I might as well actuate the gate using some form of electronics. After considering different options for a while, I decided to design a rotational blast gate that can be controlled with a servo. I hop into my design software and come up with a simple 3D-printed prototype. It includes a mount for the servo and a place for the control electronics.
For the microcontroller, I chose an ESP8266 module that has most of the GPIO pins broken out. These are supported in my home automation environment server. It occurred to me that I may need to manually actuate a blast gate every once in a while, especially the one at the floor sweep zone which doesn’t have a tool to trigger it on and off. I decided to add a button on the side of the blast gates to solve this problem. I also needed to reduce the 4” port to fit the smaller dust ports on my miter saw so I 3D printed an adapter that goes from 4” down to 2.5”.
Next, it is time to program these blast gates. I’m using Home Assistant, so I created configurations for every single one of these devices and flashed the firmware to each. When I use the miter saw, I don't want the dust collection turning on and off every time I click the button on the saw. So, I modified the automation script to wait a full minute without the saw turning on before it shuts the blast gate and turns off the dust collector.
Now that all of the zones are set up and all the blast gates are closed, I'm ready to test this whole thing out. When I turn on the table saw, I expect the blast gate to open and the dust collector to turn on. I ran a piece through the saw, and everything works great! I move on to the miter station and make a few test cuts with a brief pause between each cut. It also works just as expected! The blast gate stayed open, and the dust collector remained on for a full minute after I finished my last cut. Now we're on to zone three, the CNC router. I flipped on the switch, and everything fired up as I hoped, with a minor problem. The dust collector is so powerful that it makes the servo’s job of opening and closing the blast gate harder. The fix is just an order of operations issue. The blast gate servo needs to wait until all the suction is done before trying to actuate. This is so exciting! Finally, zone number four, the floor sweep. Remember, there is no tool to turn this on, so I press the button, which turns on the blast gate and the dust collector. Now I can sweep my floor without using a dustpan and broom! This will save so much time by having this in my shop.
Having this in my shop is a game-changer. Think about it, how many times have you gone to use a saw and been like, you know what, this is just going to be a quick little cut? And then you're coughing for five minutes because you didn't bother to turn on the dust collector. Now, everything happens automatically, and I have the peace of mind knowing that I have this system in place. If you want to build this in your shop, all the design files are available on GitHub.
Have questions or comments? Continue the conversation on TechForum, DigiKey's online community and technical resource.
Visit TechForum