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| bulldragon2 Member Joined: Jan. 28, 2009 |  Message [#1] posted on: 02-11-2009 05:50 PM CST (US).   |  |  First this may have been answered someplace else or there may be a thread elsewhere that could help...but I didn't find it. My wife is an RN. Many of the younger (actually, student) nurses have stethoscopes that have a "back ground noise eliminator". Some are mechanical (don't ask me how, but they physically invert the phase of the background noise and add it to the palpitated heart/breath sounds), while others are active (electronic ). I've been thinking about modifying a typical stethoscope, using a microphone capsule feeding a headphone amp and feeding the reverse phase output to a pair of modified IEMs (cheepies I all ready have.). The IEMs would be attached to a pair of modified earpieces. The idea here is to isolate the heart/breath sounds from the environmental noise and to allow for some fine tuning. any ideas would be appreciated., thanks |
cmoy  Administrator Joined: Apr. 13, 1999 | Message [#2] posted on: 02-11-2009 06:15 PM CST (US). | | Why do you need to modify a stethoscope when there are stethoscopes with built-in noise eliminators? Actually, I wonder why they don't make stethoscopes more like headphones. Seems to me they'd be more comfortable than something with tubes that press against the inner ear. You could even build an interface into the amplifier to record heart sounds into an mp3 recorder for later analysis or to keep on file. That would be for the doctor's office of the future, when they'd keep audio files along with image and video files in the medical records. [Edited by cmoy on 02-11-2009 at 06:15 PM.] |
| bulldragon2 Member Joined: Jan. 28, 2009 | Message [#3] posted on: 02-11-2009 06:47 PM CST (US). | | Cmoy, thanks for the ideas. Well, the ones with built in noise elimination are very $$$$, and they still use the same mechanical methods for the actual "listening" of the palpitations. Also, not everyone has the $$$, students here are very well financed. RNs aren't. USD $441 (best price so far). And RNs are expected to have their own on-shift. have a look here as an example: And many think all should be able to use a proper mechanical stethoscope. What happens if batteries or amp fail? So some sort of mechanical/electronic hybrid seems reasonable to me. It also seems ridiculously expensive for essentially a mic capsule, a headphone amp or similar and a couple of transducers (no doubt sourced from a headphone manufacturer). |
| cmoy Administrator Joined: Apr. 13, 1999 | Message [#4] posted on: 02-11-2009 07:41 PM CST (US). | |
And that's a very good reason for not using a noise-cancellation stethoscope. Can't RNs use a regular stethoscope, if they can't afford a n-c model or buy one used on the cheap? If you build one and it malfunctions, you could be liable for damages. I'd only risk it if she were a homeopathic nurse, although what is a homeopathic nurse, when homeopathic doctors can have little or no formal education? That's not a put-down of homeopathic doctors, however. I've seen very interesting ideas, devices and procedures from the minds of homeopathic docs. Lots of what they do is a crock, but then once in a while, there is a spark of genuine inspiration. [Edited by cmoy on 02-11-2009 at 07:49 PM.] |
| bulldragon2 Member Joined: Jan. 28, 2009 | Message [#5] posted on: 02-11-2009 08:26 PM CST (US). | | Well, ever nurse should be able to use a regular stethoscope. I merely want to "add" nc ability, not amplify breathe/heart sounds. If the mic/amp/headphone portion fails, then by default the stethoscope behaves as if it had no electronics. Some of the new grads and students can't do a BP without the electronic versions. Yes it makes it easier, but as students I don't think it should be permitted. My wife has been practising as an RN on a critical care floor for 10 years+. I thought by reducing background noise only, she may have an easier time hearing what she needs to. Only amplify the ambient sounds out of phase and adjust to reduce to minimal intrusions. I just can't imagine the electronics on the linked stethoscope being worth $300. |
| cmoy Administrator Joined: Apr. 13, 1999 | Message [#6] posted on: 02-11-2009 08:36 PM CST (US). | | There are plans for a noise cancellation headphone in the library. Search this forum for tips from people who've built it. If you go ahead with the project, pls post details as you proceed in the DIY forum. A noise cancellation steth could have many applications, such as automotive diagnostics. I seem to recall that service garages use some kind of steth to diagnose engine malfunctions. I do caution that when you take into account the cost of parts and time, $300 may not seem like too much money. [Edited by cmoy on 02-11-2009 at 08:39 PM.] |
| bulldragon2 Member Joined: Jan. 28, 2009 | Message [#7] posted on: 02-11-2009 10:05 PM CST (US). | | Thanks, Cmoy. Mechanic's stethoscopes usually are similar to medical ones, except that instead of the typical "bell" they use a straight pipe. As far as noise cancelling headphones, the thing is that the gain required should not be much, perhaps much less than for noise cancelling audio headphones. I will post the results if I get anywhere with this idea. |
jefnando HeadWizer Joined: Jan. 14, 2009 | Message [#8] posted on: 02-11-2009 10:18 PM CST (US). | |
Yes, headphones and earphones are more comfortable compared to stethoscope, but it is not practical at all if stethoscopes were built like headphones or earphones. The plus side of stethoscope even though they are uncomfortable, they can be removed easily and hanged with the earpiece clinging to the neck(thus freeing the hands immediately), also the stethoscopes were built in a way that there is no need to apply pressure to the ear piece to isolate the ammbient sound from the outside in order to get a clearer sound coming from the tubes, the earpiece does that for you, and It is acceptable for stethoscope to be uncomfortable but efficient because no one listens to a stethoscope for more than 5 minutes.
This is not very practical as well, doctors don't really need to keep audio files of heart sound because they can always listen to the heart sound of a patient when they need(present sound is more important than past). Why waste the time and money to do so then? |
| jefnando HeadWizer Joined: Jan. 14, 2009 | Message [#9] posted on: 02-11-2009 10:21 PM CST (US). | | bulldragon, why not buy a better stethoscope? something like the cardiologist version of any brand. It will be alittle more expensive than the regular stethoscope, but alot cheaper than the electronic ones. They may be heavier, but the bell and diaphragm amplify sound better while the earpiece is more isolating and comfortable. |
| bulldragon2 Member Joined: Jan. 28, 2009 | Message [#10] posted on: 02-11-2009 10:33 PM CST (US). | | tghe point was to see if I can do it, I guess. My wife has a favourite brand and model (Littmann-3M lightweight II) , but it is neither a cardio nor electronic one. I'd like to try to modify one to see what kind of results could be expected and if my idea works better than some of the expensive ones. |
| jefnando HeadWizer Joined: Jan. 14, 2009 | Message [#11] posted on: 02-11-2009 10:36 PM CST (US). | | well, bulldragon, if you are really going to modify a stethoscope, create a thread in DIY forum so we can discuss together. i have some theories for improving stethoscopes as well, but i just do not have the right equipment to do so.. maybe you can put those ideas into good use. |
| bulldragon2 Member Joined: Jan. 28, 2009 | Message [#12] posted on: 02-11-2009 10:40 PM CST (US). | | Jefano, a good idea. I suggested that I might try something first and post results, but we can discuss a thread in DIY ... |
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