The Internet of Blast Gates

There’s nothing quite like building out a shop filled with tools, but even that enviable task has a lot of boring work that goes into it. You’ve got to run power, you’ve got to build benches, and you need to build a dust collection system. That last one is usually just fitting a bunch of pipe and tubes together and adding in a few blast gates to direct the sucking of your dust collection system to various tools around the shop.

For most shops with a handful of tools and dust collection ports, manually opening and closing each blast gate is an annoying if necessary task. What if all of this was automated, though? That’s what [Bob] over on I Like To Make Stuff did. He automated his dust collection system. When a tool turns on, so does the vacuum, and the right blast gate opens up automatically.

The first part of this build is exactly what you would expect for installing a dust collection system in a shop. The main line is PVC sewer pipe tied to the rafters. Yes, this pipe is grounded, and s otherwise not very interesting at all. The real fun comes with the bits of electronics. [Bob] modified standard blast gates to be servo-actuated. Each individual tool was wired up to a current sensor at the plug, and all of this was connected to an Arduino. With a big ‘ol relay attached to the dust collection system, the only thing standing in the way of complete automation was a bit of code.

This project is a continuation of [Bob]’s earlier Arduinofication of his dust collection system where all the blast gates were controlled by servos, an Arduino, and a numeric keypad. That’s an exceptionally functional system that gets around the whole ‘leaning over a machine to open a gate’ problem, but it’s still not idiot-proof – someone has to press a button to open a gate. This new system is, for the most part, completely automatic and doesn’t really require any thought on the part of the operator. It’s neat stuff, and a great application of cheap Arduinos to make shop life a bit easier.

21 thoughts on “The Internet of Blast Gates

  1. Not sure cheap correctly refers to an Arduino. At least not an official one. Different story with the clones.

    Neat idea though. Surprising that this isn’t already a cheap, commercial product though.

        1. Exactly, the way he grounded it will dissipate static from a small area near the screw, but the rest of his system will get a build up of static because the plastic is a terrible conductor of electricity. He needs to attach some foil or place screws every 6in to a wire or something, there is probably a right way to do it.

          The mini shopvac for my CNC was building static and I had to run a stripped ground wire down the entire tube and leave a large coil in the dust chamber to avoid static build up. This was less about avoiding explosion and more to keep shavings from flying out when I opened up the vacuum.

  2. So he has like 1 central brain, a arduino, and all servos and sensors are connected to it by wire? That’s a lot of wire.
    On the other side, this saves him form a lot of power supplies…. not sure what I would do :)

    1. One could include parasitic turbine generators to power the electronics at each gate. Just make a small leak into the pipe that has to travel though a small turbine. There might not be enough pressure differential while the gate is open, but you could just use a small LiPo.

  3. I like the idea of an automated system, I’m just a little worried about the reliability. All these long wires and all these heavy machinery. I’m think about false triggering or wires that need to be redirected whenever a tool changes location or is being added. Also static electricity build up can be a problem, but just adding one earthed screw into meters of pipe doesn’t really makes sense to me, to be honest, it made me laugh. Why mention this in the video, referring to dust explosions and then not showing a proper solution. Like running one or multiple bare wires through the entire pipe, that’s not so difficult. Spraying conductive coating through the pipe is an option but nothing without it’s own problems (difficult to apply in long pipes and it eventually wears of, so it needs maintenance, which is easy to forget, giving you a false sense of security. Therefore just adding wire is so much easier.

    PS: but to be really honest I envy the space and equipment available in his shop, but please keep it safe.

    1. On this small scale, the wire length is nothing- if you are using the correct wire with good wiring and connection practices. Vibration, static, and noise are issues. The only thing more reliable than (shielded, twisted) wire is fiber optics, if noise, ground loops, etc are the concern. I agree with you on the bare “drain” wire in the tubes, industrial vacuum systems use exactly that. (such as in grain elevators where dust explosions occur and destroy entire buildings) I worked in a grain elevator/malt-house for a few summers in college (my dad managed the elevator) and even with the grounding system I noticed, and reported, small arcing from the metal end of a vacuum hose to metal equipment- a little worrisome! It is not enough to throw “earth” ground connections here or there, you also need to make sure all the metal parts have a very low impedance connection between them- that is “equipment grounding and bonding”

  4. I’m freaked out by the load sensors… low voltage and high voltage in the same box is a big no-no, and a metal box with a near bare circuit board floating in it… and using romex to run outside of a metal box and support the weight of the box and the cords… That just seems like an electrical hazard waiting to become a disaster.

    Others have already mentioned pvc grounding.

    1. Thanks for the link- very interesting info on the dust collection risk issue. It sounds like the bigger risk, than static causing an explosion in a home dust system, is the pile of dust sitting around and catching fire from something other than static, and fine dust in a filter with lots of air, and maybe sparks from saw blades hitting metal or similar issues.

  5. I built one of these a long long time ago. My system wasn’t nearly as automated – each machine had its own button and a red/green LED to indicate state. Before I used the machine I pushed the button, the gate opened, LED went green, all other gates closed, LEDs went red. If there was a jam the LEDs would blink red. I had a couple of magnets in the gate along with a hall sensor that detected fully open and fully closed.

    Each gate had its own processor. This was long before Arduino so it was all done with Atmel Tinys.

    It worked great for a while but eventually the gates started to jam.

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