Hearing aid

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Contemplating the possibility maybe of doing a very low cost hearing aid. But it's not something I've designed before. The musts:
Use mass market off the shelf parts, so it will necessarily be large
Decent battery life to keep costs down, not like the cheapskate ones you can get that only run a few days on coin cells. Using AAA or AA is possible.
If a chip is used it must be a very common one - and I can't think of one that would do this. The 386 has min 4-5v, Iq 4-8mA, hardly ideal, not totally ruling it out but don't love it.

So it's either a 386, which would use a massive 4 cell battery pack. AAA 0.3-0.5Ah at 8mA = 50 hours, and that's just I_q. No use at all.
Which leaves only discrete designs left. And I lack experience with very low voltage amp design or with sliding class A.  
Suggestions welcome... and not pursuing it remains an option.


NT

Re: Hearing aid
On Tue, 11 Dec 2018 15:15:17 -0800 (PST), snipped-for-privacy@gmail.com wrote:

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You might want to first survey what's currently available.  Most of
todays hearing aids are digital.  They also carry a wide variety of
options, such at Bluetooth, computer interconnect, phone interconnect,
feedback reduction (bode shifter), smartphone BT interconnect,
computer gain/freq_response/compression/etc adjustment, directional
control, hearing modes (voice, music, noisy party, etc, and background
noise reduction.  Also, FDA approval.
<https://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/HomeHealthandConsumer/ConsumerProducts/HearingAids/default.htm

Hearing Aids|NXP - NXP Semiconductors
<https://www.nxp.com/applications/solutions/internet-of-things/smart-things/healthcare/hearing-aids:HEARING-AIDS

Introduction to Hearing Aids and Important Design Considerations
<https://www.maximintegrated.com/en/app-notes/index.mvp/id/4691

Digital hearing aid design: Fact vs. fantasy
<https://journals.lww.com/thehearingjournal/fulltext/2002/02000/Digital_hearing_aid_design__Fact_vs__fantasy.6.aspx

Seven Things Hearing Aid Manufacturers Should Think About
<https://www.onsemi.com/pub/Collateral/TND6092-D.PDF

More:
<https://www.google.com/search?q=hearing+aid+design

However, if you want to design something that's really "very low
cost", I suggest that you buy some of these on eBay, take them apart,
and see if they can be improved:
<https://www.ebay.com/itm/Digital-Hearing-Aid-Aids-Kit-Behind-the-Ear-BTE-Sound-Voice-Amplifier-Audiphone-/323346991972
I suggest you avoid anything that does NOT have a rechargeable battery
as these tend to kill batteries and are therefore expensive to own.

Good luck.

--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: Hearing aid
On Tuesday, 11 December 2018 23:45:45 UTC, Jeff Liebermann  wrote:
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.
thandConsumer/ConsumerProducts/HearingAids/default.htm>
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gs/healthcare/hearing-aids:HEARING-AIDS>
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earing_aid_design__Fact_vs__fantasy.6.aspx>
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-Sound-Voice-Amplifier-Audiphone-/323346991972>
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Out of all those links the only 2 features I'm considering are compression/
agc and a volume knob. This needs to outcompete the $5 hearing aids on purc
hase price & run time.

The only real question I'm looking at at this point is what approach to tak
e with the amp. I may consider a CMOS invertor chip class D later, but want
 to start with something minimal. The first question is whether to go with  
B, AB or sliding A, then I'll look at how to implement it.


NT

Re: Hearing aid
On Tue, 11 Dec 2018 16:18:53 -0800 (PST), snipped-for-privacy@gmail.com wrote:

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Sigh.  You're hard to please.  Maybe an ear trumpet will meet your
price objective:
<https://www.google.com/search?q=ear+trumpet&tbm=isch
or something less Wagnerian:
<
https://i.etsystatic.com/6256228/r/il/092ae3/484956719/il_fullxfull.484956719_245z.jpg


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I bought a few of the non-rechargeable battery type eBay earphones for
a friend who claimed he needed just a minimal boost.
<https://www.ebay.com/itm/2-x-Small-In-Ear-Invisible-Best-Sound-Amplifier-Adjustable-Tone-Hearing-Aids-Aid/302758860505
It worked, but the batteries were expensive and didn't last very long.
1.5v at 4ma from an AG3 (typically 30ma-hr) battery.  With a class A
amplifier, the 4ma drain is continuous, so a battery would last maybe
7 hrs.  I suggest you include the cost of at least one
non-rechargeable battery per day into your cost estimate.  

When I went looking for rechargeable hearing aids, I found that they
were all digital (probably Class D) amplifiers  
<https://patents.google.com/patent/US5815581
such as the one I previously mentioned:
<https://www.ebay.com/itm/Digital-Hearing-Aid-Aids-Kit-Behind-the-Ear-BTE-Sound-Voice-Amplifier-Audiphone-/323346991972
I haven't had the opportunity to tear one apart and see if it's an
NiMH or LiPo battery or what they use for a DSP chip.  Probably
something like this inside, but I'm guessing:
<https://www.alibaba.com/product-detail/Hearing-Aid-Battery-Small-Lipo-Battery_60382616469.html
3.7V 160ma-hr.

I like to design things starting with what the customer wants, and
work back to what I think would be cool.  Besides a $5 cost (cost to
sales, not including battery, etc), what features does the customer
really need?  AGC and gain control are a good start, but things like
battery savers, rechargeable battery power, filtering, tone control,
etc are in demand.  Those are easy with digital, not so easy with
analog.  I would start with digital and only fall back to analog if
you can't make the price objective.





--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: Hearing aid
On 12/11/2018 8:24 PM, Jeff Liebermann wrote:
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  I still think retro is the way to go.
A box in your pocket and headphones, but now the box is a computer  
(smartphone) and the headphones can be blue tooth. Just seems to me the
computing power in your smart phone can be put to good use.
   I'm sure at some point there will be a great free app, that will
only hear beautiful women that think you are smart, handsome, desirable
and want to have sex with you.
  Or at least let you hear better in a crowded room.
                                    Mikek


Re: Hearing aid
On Thu, 13 Dec 2018 14:12:56 -0800 (PST), snipped-for-privacy@gmail.com wrote:

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Give them a kit instead of a finished product.  You supply the parts,
instructions, PCB, rechargeable battery, and not much else.  They can
share soldering irons, solder, creative packaging (e.g. match box),
and felt tip pen labeling.  Any village with talent will have someone
who is better at soldering than the rest, so he or she gets to build
hearing aids for the rest.  My guess is about 10% will get screwed up
during assembly, so for every dozen hearing aid kits, throw in a
"spare".  If you're stuck with SMT parts, use templates, preforms,
supply PCB's with the major parts already attached (with super glue).

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Are you expecting me to solve all these problems?  Are you expecting
to solve any of the aforementioned problems with a $5 hearing aid?  I
don't have an answer to solving such problems.  I'm an
electrical/electronic engineer, not a social engineer.  I design
products, not social and economic systems.  This is YOUR project, not
mine.  If you're intent is to make some money for yourself and/or for
your client, then we're speaking the same language.  If your intent is
reform the world on the basis of a $5 hearing aid, I can't help you or
your client.  If you give me one problem to solve, I can probably
succeed.  If you bury me in centuries of institutionalized poverty and
economic disadvantages, I can do nothing.

In the past, when someone comes to me with the next great idea, the
very first thing I ask is "what business are you in"?  If they answer
that they're out to save the world, reform society, and eliminate
hunger on the planet, I politely suggest that they consult someone
else.  If they answer that they're out to make money, or leverage the
profits into building the next great idea, I listen and try to help. I
strongly suggest you ask yourself the same question.  What business
are you in?  

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I've never been there.  What little traveling I've done was spent
dodging bullets and trying to stay out of their jails.  Even in
enlightened Israel, I was nearly arrested twice for attempting to
establish a cable TV system (details on request).

One thing I might add about 3rd world countries is that any person or
company that is even marginally successful, instantly becomes the
target of every kidnapper, extortionist, crook, tax collector, and
corrupt government official.  That's a rather powerful counter
incentive to becoming successful, which might help explain some of the
items on your list of social ills worth solving.

Actually, most 3rd world countries have an FDA or equivalent.
Currently, they can afford to kill off some percentage of their
population with badly designed or unsafe products.  Should they ever
achieve some semblance of civilization, their FDA might prove more
useful.

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Ideas are a dime a dozen.  Talent and money to make the ideas happen
are far more scarce and valuable.  Best of luck with whatever it is
you are building, selling, reforming, etc.


--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: Hearing aid
On Friday, 14 December 2018 02:02:30 UTC, Jeff Liebermann  wrote:
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You have no idea how we operate.

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I'm pointing out the $3,000 approach is not realistic. That's why I talked about cheap & basic and an LM358.

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No, what we do addresses that stuff already.

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I doubt anyone could on that basis :)

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You're asking someone who has spent 5 years doing this to ask themselves if they know an ass from an elbow.

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It was an idea in 2013.


NT

Re: Hearing aid
Martin Brown wondered
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BT stands for blue-tooth in this context.


Re: Hearing aid
On Wednesday, 12 December 2018 02:24:49 UTC, Jeff Liebermann  wrote:
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56719_245z.jpg>

Lol. I did look at those a while back wondering if ear trumpets could be an
 even cheaper option. Conclusion was that anything small enough to be pract
ical wasn't upto the job.


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ttery_60382616469.html>
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What the customer wants is 'cheaper.' The customer would like any feature a
vailable, but only if it comes at the cheaper price. Digital is a nonstarte
r here, even later in better specced versions.

I have a preliminary rough plan. You're not going to like it. The one way I
 can get the cost way down and the run time way up - which is a major facto
r in run cost - is to go retro & forsake the modern ear-based layout. I'm l
ooking at a pocket device that runs 100s of hours on a PP3. It's a sacrific
e but the upsides are major. A cheap LM358 looks like it could manage that  
with very high R headphones.


NT

Re: Hearing aid
On Wed, 12 Dec 2018 00:42:30 -0800 (PST), snipped-for-privacy@gmail.com wrote:

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Even the cheapest ear horn is more than $5.
<https://www.amazon.com/elope-Giant-Costume-Headband-Adults/dp/B01H60RAXG/>
Well, maybe not.  This one is $4.19:
<https://www.amazon.com/Jumbo-Fake-Ears-One-Pair/dp/B00362TWH6/>

Unless you have a very high sales volume, I don't think you can build
anything for $5.  I would seem that $5 is your selling price, which
would make the cost to sales about $1.11.  The last time I ran the
calculations for a US based factory, it cost $70 to handle and ship an
empty box.  That's a product with zero cost, but that carries all the
usual overhead of QA, QC, inspections, documentation, billing,
inventory, advertising, shipping, taxes, bribes, golden parachute
fund, etc.  Today, it might easily be twice that.  

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That sounds familiar.  The initial RFQ is for every feature that could
possibly be thrown into the device.  A few months downstream, when
those features have blown the budget and schedule, the customers comes
back and says something like "Just design me something that does the
basics".

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Ok, cheap junk.  You came to the right place.  

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You're wrong.  I like it.

You're describing a pendant, which has the major advantage of allowing
the use of larger components and a much bigger battery.  Cramming
everything in the ear is probably a requirement for those who don't
want to be seen using a hearing aid, but is wasted on those who don't
care, or need to use external sound belchers (POTS, smartphone, game
consoles, etc) that require attachment.

Anyway, I suggest you find a commodity hearing aid earpiece and bring
out the leads.  Grab a signal generator and measure how many
milliwatts of driver power you'll need to be able to hear something
from the earpiece.  The transducer impedance doesn't matter.  What
you're measuring is how much power is required for the EP cone or
diaphragm to move air.  That will be how much power your LM358 or
whatever will need to provide, which I suspect will be the bulk of
your power budget.

Gotta run.  I have appointment with the cardiologist to get his
approval for drugging me senseless during kidney stone surgery.



--  
Jeff Liebermann     snipped-for-privacy@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Re: Hearing aid
If are going to market this device in the US as a "hearing aid"

besides the technical hurdles, you will have to deal with the US govt medical bureaucracy.    

Calling it a "hearing assist device"  etc, I think gets you off that hook.

Radio Shack had such a device.

mark


  

Re: Hearing aid
On Wednesday, 12 December 2018 18:13:06 UTC, Jeff Liebermann  wrote:
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Lol. Those are novelty products of course, not horns. You can make a crude horn from little more than a soda bottle. If it's large enough to actually be effective, few would want to carry it around.

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The BOM is expected to be far under $1.  

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That's one of the upsides of developing world manufacture. Some of those don't even cost a dollar.


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Yeah, I don't do that. Like many things this is minimal & cheapest first, improved versions later. Cost is key.


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It needs to work & be reliable, but there won't be any DSP, so not suitable for everyone. There won't be anything spent that doesn't need to be.


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can't get the run time from a coin cell with a linear amp. can't even get close.

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I might use piezos, not sure if that's going to be practical yet. If it is that hugely reduces power requirement. If not then moving iron, which is still much higher efficiency than moving coil.

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Fun :(


NT

Re: Hearing aid
wrote:

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If the above were true, there would be nothing available for less than
$70, which is clearly untrue.  Amazon clearly disproves your
hypothesis. Therefore, I have to call "Bullshit".


Re: Hearing aid
On Thursday, 13 December 2018 03:10:36 UTC, snipped-for-privacy@notreal.com  wrote:
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It's probably true for business producing high spec goods. But not for a lot of mfrs.


NT

Re: Hearing aid
On 13/12/2018 06:42, snipped-for-privacy@gmail.com wrote:
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They have it off to a fine art but I'd be surprised if they can do it  
for much less than $20 including all the overheads that go with it. They  
have far more sales automation than most manufacturing organisations.

$70 sounds to me more like the value of the goods an order ideally needs  
to contain to be worth the effort of processing it and shipping it to a  
customer (in a typical corporate environment). Some UK suppliers charge  
you extra for small orders (in fact *Amazon* does)
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Back when I was involved in manufacturing computer systems there was  
always a computation of the economic ordering quantity/value for stock  
items and stuff urgently required by development had to fight damned  
hard to get past if the EEV had not been reached for that supplier.

You have to pay people to do all the jobs behind the scenes that allow  
the goods to get to where they are going in a timely fashion and safely.

--  
Regards,
Martin Brown

Re: Hearing aid
On Thursday, 13 December 2018 10:27:02 UTC, Martin Brown  wrote:
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n
  
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Amazon sells loads of things under $20. Think about it.


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Again they wouldn't do it for a loss.


NT

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a lot of mfrs.
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Re: Hearing aid
On 13/12/2018 10:45, snipped-for-privacy@gmail.com wrote:
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Yes. But it costs them about $10 to pick, pack and ship every order so  


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I think they only get away with it because they are subsidised by the  
Chinese state for international postage. You wouldn't be able to send a  




--  
Regards,
Martin Brown

Re: Hearing aid
On Thursday, 13 December 2018 14:22:24 UTC, Martin Brown  wrote:
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m>
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e:
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an
ey


it costs nowhere near that. You've not looked at their warehousing prices.  
And most sellers don't use Amazon's warehouse due to its costs. Big compani
es don't do a large percentage of their sales at a loss, if you think they  
do it's time for business school.


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ds
a
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ge. Again they wouldn't do it for a loss.
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makes no difference if it's free, a Chinese seller is still selling you a p




1st world costs are only relevant to 1st world sellers & buyers.


NT

Re: Hearing aid
On 13/12/2018 21:06, snipped-for-privacy@gmail.com wrote:
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Indeed. They make a surcharge on small would otherwise be unprofitable  
orders or incentivise the buyer to bulk up the order.

It depends a lot on how you cost the process of order fulfilment. If you  
are one man and a dog in shed somewhere doing it as a hobby it is  
completely different to running a massive warehouse and manufacturing  
operation with people running around with picking lists.

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In the far east and inside China it is hard to tell what the true  
manufacturing costs actually are. My instinct is that for some of their  
stuff they do sell at a loss to obtain hard currency.

I always found Korean component pricing incomprehensible when I was  
based in Japan.


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If you are making it in the third world then maybe you stand a chance.  
But I would be very wary trying to make any money on something that  




If you are doing it to benefit the recipients then more power to your  
elbow but consider using a less thirsty opamp. If you are planning on  
getting rich with this project then think again before it is too late.

--  
Regards,
Martin Brown

Re: Hearing aid
On Thursday, 13 December 2018 21:49:23 UTC, Martin Brown  wrote:
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il.
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Less thirsty opamps with suitable Vcc & V_out range aren't available econom
ically. The salvaged 358 does the job.


NT

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