Hello ya’ll. Got a question as I’m pretty new to lasers. I have an OLM3 with a full enclosure. I got the enclosure because my 7 yr old Shih Tzu stays in the room with me most all the time and I wanted to be sure she could not see the blue laser and damage her eyes.
The Shih Tzu does NOT seem to like my laser when it’s got the diode going. Is there a frequency involved she could be hearing? She’s ok with it turned on, but if I start a burn, she leaves for the other room (unless I"m holding a treat for her). Once the burn is complete she’ll come back and lay down at my feet.
My Aussie Shepard doesn’t like the laser either, with a treat in the offering, laser burn starts the Aussie leaves immediately. For a treat the Shih Tzu will stay.
I don’t have dogs at home but…
Bearing in mind that dogs have much more sensitive hearing than human beings, I fully admit that the frequencies existing in a laser machine exist frequencies that we do not hear but that dogs hear and that bothers them.
In my opinion it is perfectly possible.
Maybe with a soundproof box I can attenuate this effect.
It would take a pretty good soundproof box since even 0.5% power used for Frame has an effect. I brought the Aussie to laser room this morning for a treat. While waiting for treat, I did a “frame” with 0.5% power, she ran. 30 minutes later I went to house coached her from under the bed, put lease on, and tried to lead her to laser room again. No way she wanted to go. I picked her up (all 35 lbs) and carried her talking sweetly to her. Got her to room, gave her a treat. She’s happy with treat, but as soon as she got treat, away to house she goes. That dog is a full blown coward anyway - scared of a new leave in yard. Yep, I’ve seen her bark at leaf, then run to house.
Most likely it’s the stepper motors moving the machinery, rather than the diode laser itself, because the stepper drivers generate audible sound with harmonics up and beyond human range. The sound varies with the speed and direction of the laser head, so dogs will surely find something to dislike in there somewhere.
Being a human male of a certain age, none of the noise bothers me in the least, but it does annoy my esteemed wife.
From the stepper motors? Could be, but I’ve got the same type steppers on a desktop CNC and I don’t remember her being bothered by them. I will have to check and see. Thanks for the idea
I haven’t used my laser (XTool D1 Pro) near any of our three dogs -two Labs and one Australian terrier- so this is just an educated guess, but with anything associated with SMPS, my vote will always go for those.
There’s nothing worse than to pair audio and cheap SMPS, that’ll always end in misery.
Those contraptions may behave adequately with low to moderate power draw, but when the power demand rises, all sort of nasty interference can be expected.
Some meet the relatively loose regulations only at idle, and any power draw will increase interference greatly.
As @ednisley suggested, the stepper motors and -drivers are IMO likely candidates as well.
The power on most -if not all- of the budget end lasers is regulated with PWM signal, so in theory the laser head might be able to emit high frequency noise as well.
If the pulleys and the toothed belts do not fit perfectly and one or the other doesn’t have air grooves, the air squeezing out will emit whining noise (just like the timing belt on a car or a bike), but obviously only when there’s rapid movement.
It’ll take a while before I’m able to use my laser the next time, but since I happen to have recently bought an ultrasonic detector with a parabolic dish for electronics fault finding, this will be a perfect opportunity to test if it works at all.
Because of its intended application its very easy to pinpoint the culprit if any, but it’ll unfortunately only tell the amplitude, not the frequency.
If You happen to know any bat enthusiasts, they will have bat detectors and those will reveal also the frequency.
From the frequency it’s relatively easy to figure out the source.
I’m down to two cats and 1 dog… I cherish them, and keep them out of areas that could cause damage to/from them…
I shut them out of the room… the reality is that you don’t know what’s going to happen and how an animal will respond. don’t risk a vet bill or living with knowledge that you may have harmed your best friend…
This also goes for vapors created in the process.
It may be comfortable for you to have them, but it’s not really for them or worth it in the end if something unexpected happens.
They are here when I design, but when I start to fire up the machine, they’re out of there…
If the stepper drivers are capable of micro stepping, that also uses a PWM type signal and though I don’t know what the typical laser would use, other systems I have experience with (robotics) used PWM frequencies in the 20KHz+ range.
This could easily disturb Phydeaux.
DO NOT allow your pets around your lasers.
I have 2 dogs a Rhodesian Ridgeback and an English Bulldog, both love being with me in the shed however, i don’t allow them in when I’m running my cnc or lasers, i spoke to their vet and he said that the laser and stepper motor frequencies have bad effects on an animal’s hearing. He explained it to be the same intense pain as a migraine.
Thank you Sam for a detailed response. You make several good points. I’ve got several SMPS in use, from computers to the desktop CNC machine and never noticed any issues in the past with the dogs. BUT - as we all know the quality of SMPS varies from manuf to manuf.
Jack, I’m as invested in my pets are you are. That’s why I’ve got the enclosure for laser, and it on a table so there’s no danger to pets from the laser. Plus, when I start moving around the laser like I was going to use it, they leave the room. The Aussie heads back to house to hide under bed, the Shih Tzu goes to the shop (next room) to sleep while the laser is going. Once it’s finished, she comes back. So, I think there is a freq they’re hearing.
Short version of below: play with $33 setting, change it maybe x5 up (should be safe for most hardware), see if dogs behavior changes. Also consider smell. And the fact that dogs already trained to associate activity of the laser machine with smell, even if it coming later.
Long story: I’m agreed with most folks that somehow some PWM is the culprit. But I would like to expand this thesis beyond stepper, to laser light and possible solution, if you are as curious and up to some extra effort:
First of all would be nice separate motors from laser. As you’ve stated that idle is not a problem and only actual burn is, it can be motors or can be full power of the laser. To figure it out: set some burn job with power set to zero and see if behavior of your dogs is the same. Though it can be Pavlov’s dog effect where sound of steppers will cause dogs to expect secondary effect and to take action preemptively.
Now the possibility that I do not see in the thread: micro-explosions caused by the laser: These are the characteristically micro POPs, with very wide acoustic spectrum. They are actual explosions when material evaporated or transition to gaseous state. OLM3 is GRBL based. Base code for GRBL has setting $33 to change laser PWM frequency, hopefully Orthur did not edit it out. Read this setting, see what it is and play with it. To get out of audible by dogs band you probably have to change it times, not presents. Going x10 or /10 is OK. With varying laser PWM you most likely will observe your power curve will also change, this is normal. As a fact you may find more optimal curve for specific material if you are running grayscale or speed variable power.
Then another opportunity maybe smell? Dog’s obviously more sensitive. This maybe indication to get enclosure vented to the outside.
Thanks for the comments. I don’t mind playing with some stuff at all. I might have mentioned the steppers in the desktop CNC nor the 3D printer seem to bother them, but didn’t really notice. Hard to determine which is bothering them, since when they see me go toward the laser and check anything they tend to leave before the burn is even turned on. They’ve learned by watching and know when it’s coming. The Shih Tzu doesn’t mind near so bad. If she’s sitting in my lap she tends to stay, but then she rides on lawnmower when I’m mowing lawn.
Give me a couple days to finish up a couple of projects. AND, thank you for your comments and interest.
Ken,
As your dogs already preconditioned - I do not think you will be able to complete these tests with them, you need fresh subjects. Recruit neighbor’s dogs.
We have a schnauzer. All I need to do is move toward my Laser, and he has the doorbells ringing. We have a row of bells on each side of the door. This way, he can tell us if he wants in or out, it works well. He hates the Laser, and I also might add there are certain sounds that my phone has at times. This will cause him to leave.
I like the idea of bells by the door. Wish my dogs were smart enough for that… perhaps the Aussie would be, but the Shih Tzu are ranked as pretty dumb dogs, as in 127th dumbest of 134 breeds, or some number like that. My dogs tend to scratch at the door - sorta hard on paint:)
