William Grill had a problem with noise distraction at home. Over the summer, vacationing visitors provided a wealth of noise that needed to be dampened. To solve the problem, Grill added some noise of his own -- continuous static noise to drown out the distraction.
His small, inexpensive random noise generator produces digital noise, which has the advantages of being easily repeatable, free of calibration, and inexpensive to produce. This offering runs on batteries and can be used with headphones as a noise mask to eliminate the sounds of rowdy gamers, crying babies, and gossiping grandmas.
I find it interesting that you can use noise to block noise. Since I haven't heard this gadget, I'm not sure whether the generated noise would be as irratating as the noise being blocked. Apparently it isn't.
When I was in the Mormon Church many years ago, there was white noise piped to speakers in the hallway, so that one could not listen in on conversations in the classrooms or offices. One day lightning damaged the sound system. The amplifier system was in a closet and consisted of several 100W power amplifier modules, a white noise generator, preamplifier and power supply. The sanctuary volume was remotely controlled from the stage. The power amplifier that powered the sanctuary speakers was damaged by lightning, and I temporarily replaced it with the masking system amplifier which was identical to it, but set to a much lower level. I repaired the power amplifier and being identical to the others, I plugged it into the masking amplifier slot. I forgot to turn the gain down and when I turned the system on, it sounded like the space shuttle was being launched from our church hallway.
Until called upon to repair the sound system, I just thought that the soft rushing sound I heard in the hallway was the air conditioning. Until then, I had never even heard of a masking system.
I used the same technique that Mr. Grill did to generate pseudo-random numbers for a PIC program I wrote once. I copied a random noise generator off the web, like Mr. Grill did and like him, I wrote software code to emulate the function of the hardware. The main program would just look at the number in one of the registers to get a "random" number. I only needed an 8-bit random number, but 16 bits would have been available, had I implemented all 16 bits. There is probably no limit to how many bits you can do with this technique.
Great job, William. Comments in your code would be helpful, however.
I found this device to be quite interested as well. I tell my Electrical Engineering Tech students that in the world of high tech microcontrollers and embedded software, the Common Emitter Amplifier will always have a place in our society. These device just illustrated my student comment.
Fun little project but I have a different application. My husband loves white noise. He falls asleep very easily to the noise of a vaccuum cleaner or the dryer. My biggest problem would be if using this project for noise cancelling that hubby would fall asleep...but in his case it would be a great all natural solution to insomnia...
I guess everyone is different, far911. We have an air filter in our bedroom that also generates white noise and becomes louder when the filter starts to get clogged. It keeps me awake but puts hubby to sleep. I would much rather fall asleep to some relaxing soft music but white noise is very distracting to me.
I also find noise iritating, especially when it is added to mask other sounds.
The most offensive noise, though, has been added to a local food establishment to simulate the sounds of a crowd having a good time. My meal companions had not noticed it until I pointed out that none of the other patrons were being that noisey, and as they looked around they realized that it was true, others were quietly talking in their own booths, while the ambient din was much louder than that. This is especially bothersome to me because I have damaged hearing, and the increase in ambient noise tends to make having a conversation difficult.
But even worse than that is the background "music" played in both offices and some stores. This is never the good quality stuff, but rather the stuff that is available much cheaper because nobody liked it. ( I am referring to the copyright fees). That garbage, played through paging trumpet speakers, is quite offensive to my ears.
I hear what everyone says about the pluses and minuses of white noise. Some like it, while some don't.
Here's an odd, somewhat off topic question. I work in a noisy environment, and need a timer that would normally beep. I have to look out the window, so I can't look at the timer, so I need something that "bumps" - like a vibrator that vibrates once. Some cell phones have this when you turn them on - you hold the on button for three seconds, and you feel them "jump".
What is this component called. I've searched "thumpers" (and learned a new game), and searched "vibrators" (and got some interesting stuff).
Reminds me of a sine wave generator using a complicated counter/prom/DAC instead of a simple Wien Bridge oscillator. Really, is this any better than a back-biased zener (white noise genertor) and audio amplifier?
@zeeglen: Good point but I feel its good to try out all that is available so at least we can figure out the issues behind them and start addressing them. Who knows the output can be THE one in the future.
I would suggest that adding more noise to mask other noise may indeed be able to do that, BUT there is a problem in that thye ambient noise level increases. That in turn makes any desired communication more difficult.
A local tavern has installed a system that raises the abient noise level to that of a large bar on a crowded Saturday night, which means that quiet conversation in a booth is not possible. So I will not go there again, and I hope that they go broke, possibly they would learn that such tricks are dumb. It is one thing to attempt to giv the impression that "everybody is here", but it does not work for a lot of people.
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