What warning do you use for loud machines?

When notifying others in the shop that you are about to activate a loud machine, what method do you use? My team adopted the word “NOISES” before using the cutoff saw, but I recall that there is something more professional out there. My memory is going. Please assist. Thanks.



Shout the name of the tool being turned on if that’s the source of the noise. I.e. “SAW”, “MILL”, “GRINDER” partially because it’s fun but also because each tool will have different safety requirements when in use. Yes the sound warning in general is nice but for grinding you might also want a warning about possible sparks. Based on where the tools are in the shop we also know what areas to avoid.

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I like this idea! My team doesn’t currently do anything like this, but we do always yell “ENABLING” before enabling any of our robots.


I do similar. I just shout “LOUD NOISES” like brick from anchorman.
some of the team does it. some dont.



It started 2022 when we vented pneumatics when ppl were working around the bot and just kinda stuck.

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In highschool, the biggest culprit for really loud noises was our CNC plasma cutter/table. As a result, whenever we went to start a cut/program, we were expected to shout “fire in the hole!”. Seemed to work well in that application.

In a similar but different vein, whenever a student started welding (even though they were in a welding area with curtains), they were expected to shout “eyes!”, so anybody nearby knew to avert their gaze from that general direction (or lower their mask).

Fire off three or four rounds from one of these puppies before starting the circular saw.

Very /s

We just ran the NIOSH app to confirm noise levels are within OSHA limits… but methinks another habit to at least give people warning might be good too. Thanks for the suggestions!


we yell “CUTTING”

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Safety Ears

(Use a muffler on your release valve!)

I find many times it’s the material or how the tool is used that create abnormally loud noises. Some geometries just seem to resonate in the worst way.

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I used to work in a place that used rivet guns, hammer type. And a few other noisy tools.

It was expected that before you started a salvo of rivets, you’d shout “NOISE!!!1!” to warn others around to cover ears (and, in some cases, cover microphones).

Some people didn’t… and ran into unexplained issues related to the tools in question. One or two yelled loud enough to be heard in a nearby conference room. We liked the second group more for some reason.


Just shout “ROBOT!” as loud as you possibly can. This is the safest way.


Anyone working in an area with a loud tool has ear protection on. No need to scream anything.


And I’m sure the people in the conference room liked them too?

I don’t recall that–I only heard about it second-hand.

If my crew hollered “NOISE” you knew it was going to go for quite a while–it meant we were using a very large nibbler. We didn’t do that often.

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“Close your ears!” is my favorite for its illogical nature. Usually in the context of the miter saw.

At Stage Crew(Theater Tech), we call out “NOISE” and wait for a response back from the other people in the shop to say: “Thank you, Noise!”

That is what we do at stage crew but on the team I have never heard anyone say anything before turning on tools. I hear people say “Enabling!” when the enable the robot but nothing else.

Also at Stage Crew, we do call outs for various safety things, such as: “on your ladder” “cable swinging” “rope splashing down” “lose hardware” just to name a few. They all require a “Thank you!” response before you do whatever you are about to do. At Stage Crew, we also wear eyes and EARS whenever using any type of power tool(including drills and impact drivers). I never see that at robotics but I can only encourage people so much. (There are also 4x people in the shop at robotics vs at crew so things like eyes you take on and off all the time bc you know what is going on around you)

FYI, Eyes = Eye protection, Ears = Ear protection, Also at crew we work at 20+ feet up in the air quite often to hang lights


That works great if those areas are well separated/defined, or the loud tools are often in use.

But I can imagine there are a number of teams out there (we’re one of them) where your build space is rather “compact”, and you don’t often use these loud tools. In this scenario, constant use of hearing protection isn’t practical IMO, in which case, having a way to communicate quickly and clearly to others that things are about to get loud, is important.


In our old room we had a large space with plenty of distance separation, but no physical barriers where you might not need hearing protection (we used a meter to check from the desk area in question). It was low enough to not need hearing protection but the warning was good if they were in the middle of a discussion so they could end their thought and wait a second.

In our new room the space is even smaller so now the desk people will have to keep a pair of ear plugs with them and only put them in as needed. They can’t keep em in all meeting or else the CAD team and others in that small space won’t be able to hear each other talking. The warning system gives everyone time to gear up as needed without requiring 24/7 hearing protection and making normal conversation difficult.


As a better solution to shouting our team had thought mapped a system of warning lights for each machine and in the corners of each room.

Based on the levels on the chart below:

You would have a powered module that has a red, yellow and green light on it. This could be a real stack light like the ones Adafruit sells or just colored lights, however the stacklights usually include a buzzer too which can get people’s attention that the light is changing status or it needs their attention.

A module is ideally an Arduino or ESP8266 device with a microphone or sound level sensor attached to log sound levels over time as well as controlling the stacklight. If you used an esp8266 you could have it host a simple webpage over it’s own local WiFi to download the log files for analysis.

If any sensor goes above a set threshold for any time that can start the warning yellow light and then when you absolutely must have earplugs it goes to red. Again if you had esp8266 students could manually set a light to a set mode before they start a shop tool to give people a warning.

Each module is calibrated and tuned with a real DBA meter to match the chart above. Then you place them all over where ever you might need the warning but also have power. Downside is this is kind of expensive per module and outrigging our lab with this system would’ve been about $80-90 per module * 7 modules. I’m sure we could get the cost down with a custom PCB definitely but that’s out of our skill set so all development kit items.

CNC mill bench, Bridgeport, Lathe, Horizontal Bandsaw, Grinder and Chopsaw are the loudest machines we own. They are all in one half of our lab so we would ideally put two in the corners of that room, one near the Chop saw, bandsaw and CNC mill each, and then two on the other side of the lab in the desk area.

The upside is if you have power to the machine you likely can find the right power for a small accessory device. The corner mounted ones are much harder.

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