Re: How Loud is Too Loud? (Cal Games)
 

What did you say?

(j/k)

EDIT: Our ball lift made a significant amount of noise this past year and I was impressed. And, my fingers were comfortable in my ears at times.

Re: How Loud is Too Loud? (Cal Games)
 

WHAT?


If you are really concerned about the noise level itself borrow a dB meter from someone and measure the levels.

There are safety standards for noise levels and hearing damage. If your robot is loud enough to cause hearing damage then people standing nearby would need earplugs, and you should not run the shooter in the pit area.

Re: How Loud is Too Loud? (Cal Games)
 

See, this is why I bring earplugs to FIRST events. (And you thought it was because I usually wind up near SPAM.)

I might suggest a rule that MIT's 2.007 course uses in their competition, known as the Naked Phone Booth Rule. Basically, if you wouldn't want to be in a phone booth with your device while naked (for two minutes, for our purposes), it's probably not a good idea to use it.

Re: How Loud is Too Loud? (Cal Games)
 

I have always been of the opinion that if the mechanicals are making noise they are trying to talk to you. I would listen and try to determine the problem. It might just be that at speed a part of the mechanism is hitting another part as in something is just slightly out of alignment. Look for wear spots on your rotating parts. Could be that the sprockets are not parallel and in the same plane. The chain would make a distinctive knock each time a sprocket tooth attempts to engage a chain link. The faster the speed the more (and louder) the knocks.

Re: How Loud is Too Loud? (Cal Games)
 

On a serious note, refer to the table linked to below.
http://www.occupationalhearingloss.c...aring_loss.htm

Under OSHA rules, no exposure above 115 dBA is allowed, however short.

So, this answers the question: How Loud is Too Loud?
If you have concerns, borrow or buy a sound level meter.

Yes, there will be a sound meter available at the Cal Games...

Eugene
(President of the WRRF)

Re: How Loud is Too Loud? (Cal Games)
 

Thanks that's really helpful. I would say our robot measures somewhere around the 90 level :o

Although we haven't found a solution to the problem (a five day solution that is :o ) we have managed to adjust our shooter so that we only have to reach "jackhammer speed" for a very short time.

As for metal fatigue it has surprisingly held together quite nicely and there are no visible signs of damage.

Re: How Loud is Too Loud? (Cal Games)
 

Only 90 dbA?, you can run that all day and we will call it entertainment!


Eugene

Re: How Loud is Too Loud? (Cal Games)
 

If you think the problem is your shooter is out of balance it should be relatively easy to eyeball the system and see where it is not symetrical about the center of rotation

and to guesstimate the amount of weight you would have to add to the other side to balance it - like they do with the lead weights on car tires.

regarding metal fatigue, I dont think you will see any visable signs until something breaks. After a part has failed an experienced M.E. can look at the break and tell why it failed (crystalized, sheared, cut...)

Re: How Loud is Too Loud? (Cal Games)
 

This is a good explanation but adding to this, the "A" scale is a frequency dependent curve that tries to approximate the inverse of human hearing sensitivity. As such it is less sensitive to areas where the human hearing is less sensitive. However, the offending noise is still there.
Many venues and outdoor arenas are now instituting noise level ceilings on performances. 110 dBA seems to be the defacto standard but the measurement is still an issue. Sounds decrease by the inverse square law with distance. So the issue is where do you measure the sound level. In arenas, it is acceptable to take an average of the seating area but any seat that exceeds the standard should be corrected by some means to come into compliance. Outdoor venues have to comply with neighborhood standards such that sound levels at the closest house must stay within local ordinance for the time of day. (local sound level ordinances vary between daytime and nighttime.) With a standard FRC playing field the drivers have less exposure than the judges and field people.

Re: How Loud is Too Loud? (Cal Games)
 

:D QFT! Not like this is a football game where you've got to yell across a field.