Medical Device Alarm...

[Ricketty C]

I see information about medical alarm sounds with specific harmonic content.. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

 

[Silvar Beitel]

On Sunday, September 6, 2020 at 3:24:27 PM UTC-4, Ricketty C wrote:

I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

Go to the next level up:

<https://foxtrot.com/2020/09/06/alarming/>

--
Silvar Beitel

 

[Joe Gwinn]

On Sun, 6 Sep 2020 12:24:19 -0700 (PDT), Ricketty C
<gnuarm.deletethisbit@gmail.com> wrote:

I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

I saw a medical ~standard on the sounds of medical devices. The
intent was to make only urgent warnings sound urgent, and so on, to
combat alarm fatigue in hospitals. I cannot find the article, but
Google should help. I think I mentioned on S.E.D.

Another reason to have harmonics is so one can estimate how far away
the alarming unit is. We do this by the change in spectrum at the
sound travels, due to the increased relative attenuation of higher
harmonics.

Joe Gwinn

 

[Ricketty C]

On Sunday, September 6, 2020 at 4:59:26 PM UTC-4, Silvar Beitel wrote:

On Sunday, September 6, 2020 at 3:24:27 PM UTC-4, Ricketty C wrote:
I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

Go to the next level up:

https://foxtrot.com/2020/09/06/alarming/

If nothing else, this group can be good for comic relief.

--

Rick C.

+ Get 1,000 miles of free Supercharging
+ Tesla referral code - https://ts.la/richard11209

 

[Ricketty C]

On Sunday, September 6, 2020 at 5:10:14 PM UTC-4, Joe Gwinn wrote:

On Sun, 6 Sep 2020 12:24:19 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

I saw a medical ~standard on the sounds of medical devices. The
intent was to make only urgent warnings sound urgent, and so on, to
combat alarm fatigue in hospitals. I cannot find the article, but
Google should help. I think I mentioned on S.E.D.

Another reason to have harmonics is so one can estimate how far away
the alarming unit is. We do this by the change in spectrum at the
sound travels, due to the increased relative attenuation of higher
harmonics.

Yes, I found many articles. It was only today I found one from Malory (an alarm maker) that indicated IEC 60601-1-8 is voluntary. It is actually easy to meet once the details are understood.

It seems like the sawtooth is the way to go, especially since it is simpler circuitry. I just need to identify a speaker. Not so easy at 250 Hz in a small place.

--

Rick C.

-- Get 1,000 miles of free Supercharging
-- Tesla referral code - https://ts.la/richard11209

 

[Tabby]

On Sunday, 6 September 2020 22:11:02 UTC+1, Ricketty C wrote:

On Sunday, September 6, 2020 at 4:59:26 PM UTC-4, Silvar Beitel wrote:
On Sunday, September 6, 2020 at 3:24:27 PM UTC-4, Ricketty C wrote:

I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

Go to the next level up:

https://foxtrot.com/2020/09/06/alarming/

If nothing else, this group can be good for comic relief.

I can\'t find the link for the ultimate alarm. It\'s basically a motorised boxing glove. Rather than a joke, someone with a sleeping disorder made it to wake in the morning.


NT

 

[Clive Arthur]

On 06/09/2020 20:24, Ricketty C wrote:

I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

A sawtooth sounds a bit like an angry wasp, maybe we\'ve evolved to
notice it more.

--
Cheers
Clive

 

[Martin Brown]

On 06/09/2020 20:24, Ricketty C wrote:

I see information about medical alarm sounds with specific harmonic
content. To meet the requirement requires using odd and even
harmonics. That seems to form something like a saw tooth wave.
Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth
wave will be no lower than -14 dB which is within the -15 dB spec,
likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more
attention getting that something more pure? Why not a square wave?

A very pure sine wave sounds surprisingly restful.

A square wave sounds just about as crude and horrible as you can get.

I\'m guessing the harmonic content of the square wave is lower and at
higher frequencies so harder to meet the spec as written anyway.
Does a square wave sound worse? I know I\'ve heard them plenty of
times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the
phase accumulator which is already a sawtooth ramp.

A rough exponential sawtooth was very easy to generate and sounds
alarming enough without being too annoying or distracting.

If you recall the Three Mile Island disaster the operators spent the
first 15 minutes figuring out how to silence all the damned alarms and
klaxons so they could hear each other over the din! Only then were they
able to get on with the task in hand of trying to prevent a meltdown.

Human factors come into play where alarms and alerts are concerned.

--
Regards,
Martin Brown

 

[amdx]

On 9/6/2020 8:50 PM, Tabby wrote:

On Sunday, 6 September 2020 22:11:02 UTC+1, Ricketty C wrote:
On Sunday, September 6, 2020 at 4:59:26 PM UTC-4, Silvar Beitel wrote:
On Sunday, September 6, 2020 at 3:24:27 PM UTC-4, Ricketty C wrote:
I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.
Go to the next level up:

https://foxtrot.com/2020/09/06/alarming/
If nothing else, this group can be good for comic relief.
I can\'t find the link for the ultimate alarm. It\'s basically a motorised boxing glove. Rather than a joke, someone with a sleeping disorder made it to wake in the morning.


NT

When I was about 14, I had some scouting outing that required I get up
very early to go to.

 I had an alarm clock, but didn\'t think I\'d hear it. I had a Radio
Shack sound activated relay

I built on those red plastic boxes. I connected that to a radio and when
the alarm went off,

it triggered the relay and the radio started blasting at full volume.  I
got up!

Mikek


--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

 

[server]

On Sun, 6 Sep 2020 12:24:19 -0700 (PDT), Ricketty C
<gnuarm.deletethisbit@gmail.com> wrote:

I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

At least the 1000 Hz sine wave is very awful indoors due to the
standing waves, so you can loose orientation quite quickly.

In a room with potentially multiple alarm system, you should be able
to reliably locate which device generated the alarm.

 

[Joe Gwinn]

On Sun, 6 Sep 2020 14:49:57 -0700 (PDT), Ricketty C
<gnuarm.deletethisbit@gmail.com> wrote:

On Sunday, September 6, 2020 at 5:10:14 PM UTC-4, Joe Gwinn wrote:
On Sun, 6 Sep 2020 12:24:19 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

I saw a medical ~standard on the sounds of medical devices. The
intent was to make only urgent warnings sound urgent, and so on, to
combat alarm fatigue in hospitals. I cannot find the article, but
Google should help. I think I mentioned on S.E.D.

Another reason to have harmonics is so one can estimate how far away
the alarming unit is. We do this by the change in spectrum at the
sound travels, due to the increased relative attenuation of higher
harmonics.

Yes, I found many articles. It was only today I found one from Malory (an alarm maker) that indicated IEC 60601-1-8 is voluntary. It is actually easy to meet once the details are understood.

It seems like the sawtooth is the way to go, especially since it is simpler circuitry. I just need to identify a speaker. Not so easy at 250 Hz in a small place.

Do you actually need to have the 250 Hz fundamental? If you have
multiple harmonics of the fundamental, the brain will reconstruct the
fundamental. So just generate the waveform and feed it to the
annucator, and see how it siounds.


Joe Gwinn

 

[Ricketty C]

On Monday, September 7, 2020 at 6:43:37 PM UTC-4, Joe Gwinn wrote:

On Sun, 6 Sep 2020 14:49:57 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

On Sunday, September 6, 2020 at 5:10:14 PM UTC-4, Joe Gwinn wrote:
On Sun, 6 Sep 2020 12:24:19 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

I saw a medical ~standard on the sounds of medical devices. The
intent was to make only urgent warnings sound urgent, and so on, to
combat alarm fatigue in hospitals. I cannot find the article, but
Google should help. I think I mentioned on S.E.D.

Another reason to have harmonics is so one can estimate how far away
the alarming unit is. We do this by the change in spectrum at the
sound travels, due to the increased relative attenuation of higher
harmonics.

Yes, I found many articles. It was only today I found one from Malory (an alarm maker) that indicated IEC 60601-1-8 is voluntary. It is actually easy to meet once the details are understood.

It seems like the sawtooth is the way to go, especially since it is simpler circuitry. I just need to identify a speaker. Not so easy at 250 Hz in a small place.

Do you actually need to have the 250 Hz fundamental? If you have
multiple harmonics of the fundamental, the brain will reconstruct the
fundamental. So just generate the waveform and feed it to the
annucator, and see how it siounds.


Joe Gwinn

The spec says withing 15 dB of the fundamental, which is about 5.6x. It can be either direction so I suppose the fundamental can be attenuated, but the first harmonic is about 500 which is still out of range for many small transducers. I guess we can leave that mounted to the chassis somehow and wire with a connector. Then it won\'t impact the board design and that can proceed.

I doubt there will be adequate resources in the FPGA, but I\'d like to be able to make it talk as a joke.

--

Rick C.

-+ Get 1,000 miles of free Supercharging
-+ Tesla referral code - https://ts.la/richard11209

 

[gray_wolf]

On 07/09/2020 5:43 pm, Joe Gwinn wrote:

On Sun, 6 Sep 2020 14:49:57 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

On Sunday, September 6, 2020 at 5:10:14 PM UTC-4, Joe Gwinn wrote:
On Sun, 6 Sep 2020 12:24:19 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

I saw a medical ~standard on the sounds of medical devices. The
intent was to make only urgent warnings sound urgent, and so on, to
combat alarm fatigue in hospitals. I cannot find the article, but
Google should help. I think I mentioned on S.E.D.

Another reason to have harmonics is so one can estimate how far away
the alarming unit is. We do this by the change in spectrum at the
sound travels, due to the increased relative attenuation of higher
harmonics.

Yes, I found many articles. It was only today I found one from Malory (an alarm maker) that indicated IEC 60601-1-8 is voluntary. It is actually easy to meet once the details are understood.

It seems like the sawtooth is the way to go, especially since it is simpler circuitry. I just need to identify a speaker. Not so easy at 250 Hz in a small place.

Do you actually need to have the 250 Hz fundamental? If you have
multiple harmonics of the fundamental, the brain will reconstruct the
fundamental. So just generate the waveform and feed it to the
annucator, and see how it siounds.


Joe Gwinn

I would think at this point in time the construction and optimization of alarm
tones should be well known or is this usually done on a one time individual
basis? ca 1961 I worked on a data handing device that had an error alarm that
sounded like a very well tuned dripping faucet. It wasn\'t painfully loud but was
impossible to ignore and impossible to sleep through.

 

[Ricketty C]

On Wednesday, September 9, 2020 at 4:49:23 AM UTC-4, gray_wolf wrote:

On 07/09/2020 5:43 pm, Joe Gwinn wrote:
On Sun, 6 Sep 2020 14:49:57 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

On Sunday, September 6, 2020 at 5:10:14 PM UTC-4, Joe Gwinn wrote:
On Sun, 6 Sep 2020 12:24:19 -0700 (PDT), Ricketty C
gnuarm.deletethisbit@gmail.com> wrote:

I see information about medical alarm sounds with specific harmonic content. To meet the requirement requires using odd and even harmonics. That seems to form something like a saw tooth wave. Looks like the first four harmonics, 2, 3, 4 and 5th in a saw tooth wave will be no lower than -14 dB which is within the -15 dB spec, likely why they picked this number.

Any idea why they picked this waveform? Do you think it is more attention getting that something more pure? Why not a square wave? I\'m guessing the harmonic content of the square wave is lower and at higher frequencies so harder to meet the spec as written anyway. Does a square wave sound worse? I know I\'ve heard them plenty of times, but I can\'t recall at the moment.

The good news is this eliminates the sine calculation. Just use the phase accumulator which is already a sawtooth ramp.

I saw a medical ~standard on the sounds of medical devices. The
intent was to make only urgent warnings sound urgent, and so on, to
combat alarm fatigue in hospitals. I cannot find the article, but
Google should help. I think I mentioned on S.E.D.

Another reason to have harmonics is so one can estimate how far away
the alarming unit is. We do this by the change in spectrum at the
sound travels, due to the increased relative attenuation of higher
harmonics.

Yes, I found many articles. It was only today I found one from Malory (an alarm maker) that indicated IEC 60601-1-8 is voluntary. It is actually easy to meet once the details are understood.

It seems like the sawtooth is the way to go, especially since it is simpler circuitry. I just need to identify a speaker. Not so easy at 250 Hz in a small place.

Do you actually need to have the 250 Hz fundamental? If you have
multiple harmonics of the fundamental, the brain will reconstruct the
fundamental. So just generate the waveform and feed it to the
annucator, and see how it siounds.


Joe Gwinn


I would think at this point in time the construction and optimization of alarm
tones should be well known or is this usually done on a one time individual
basis? ca 1961 I worked on a data handing device that had an error alarm that
sounded like a very well tuned dripping faucet. It wasn\'t painfully loud but was
impossible to ignore and impossible to sleep through.

The IEC standard is just a recommendation and even then it doesn\'t directly specify all the details. Some devices use a simple fixed tone of higher frequency. Some devices use a fixed tone of a frequency used for a general alarm with a well defined cadence. Other devices use a set of tones with cadences specific to the level of severity of the alarm event. One document I read claimed the IEC standard was enforced by the customers requirement to adhere to the standard rather than a national requirement.

So there is commonality to greater or lesser degrees. It seems to not so much be about the basic function of the alarms, but rather about the finer points.

The thing that really makes this hard is knowing that if I plan an architecture for the requirements now, I will need to redo it later when they change. Very few people on this project want to dig into the requirements aspect of the matter.

I think this circuit will be table driven for both the processing and the alarm presentation. Hand shakes to coordinate with the alarm sources. It\'s the sort of thing that thinks about itself when you aren\'t thinking.

--

Rick C.

+- Get 1,000 miles of free Supercharging
+- Tesla referral code - https://ts.la/richard11209