Maker Pro
Maker Pro

Magnetic field of a solenoid

R

Rich Grise, Plainclothes Hippie

Jan 1, 1970
0
I was a big skeptic regarding electric brushes. Until I used one. It does
clean a whole lot better. Also, since then the dentist doesn't find any
serious mineral buildups near the gum line anymore.

A long time ago we had a brainstorm session at a med ultrasound company,
to come up with product ideas. The sky was the limit. So we gathered in
little groups and ours had on its list, you guessed it, an ultrasonic
toothbrush. Laughing was prohibited but the guys were rolling on the floor
holding their bellies. Needless to say we left the stage like wet dogs. A
few years later Philips built one and still makes oodles of money. We
could all be on our own islands now :-(

You must be talking about consumer products - some decades ago, I had
a cleaning and they had an ultrasonic scraper thingie, but this was
used by the pros - and from the way it sounded and felt, it wouldn't
have gone over well as a consumer product.

So, how does the ultrasonic toothbrush work? Is it like a little nylon
chipping hammer? ;-)

I have an idea for a turbo paint scraper; the Kirby patent on the
turbo-brush should have expired by now...

Cheers!
Rich
 
C

CWatters

Jan 1, 1970
0
Rich Grise said:
So, how does the ultrasonic toothbrush work? Is it like a little nylon
chipping hammer? ;-)

Just makes the head vibrate. It feels very odd for the first two weeks.
After that it feels strange when I have to use an ordinary brush and teeth
don't feel as clean either.
 
J

Jim Thompson

Jan 1, 1970
0
Very few people who use manual toothbrushes do as good a job brushing as those
who use electric brushes. Your argument is kinda like saying that people who
are too lazy to write things out long-hand rather than a word processor
deserve to get carpal tunnel syndrome. :)

I found the Sonicare just too violent for my psyche ;-)

But I find the Crest SpinBrush Pro quite nice, and it fits into my
engineering regimen... just slowly walk it around all the teeth,
fronts, backs, tops... rinse in hot water.

Grise is an idiot.

...Jim Thompson
 
J

Joerg

Jan 1, 1970
0
Joel said:
That's when you're supposed to look around the room and see if there are
enough people *not* laughing to run off and for, your own company. :)

Coincidentally that subsidiary was shut down a short time later and we
tried exactly that. Had all biz aspects covered between four of us,
engineering, software, sales & marketing, accounting. In the US most VCs
would have drooled over that kind of constellation, the guys on Sand
Hill Road would have sent a stretch limousine to ferry us in.

However, this was in Germany and it was next to imposible to raise funds
there. Banks usually only lend you money if you have a huge collateral.
IOW only when you don't really need the loan. VC was almost non-existent
back then.
 
B

Benj

Jan 1, 1970
0
Klaus said:
That sound almost Star-trek like.

Ignore Uncle Al. He's just discovered induction along with some clowns
at MIT who think they are onto something exciting. He thinks a few
feet at 40% is amazing. Tesla did Miles!
I just need 100mW

So do you HAVE to use induction? How much space do you have. With a
high enough frequency you might use a capacitive coupling through
2mm.

I also agree with two Ferrite Pot Coil halves. But, I do understand
the "standard part" thing too. Hmmm. I once made a magnetic
material tester like this. I got some pot cores and the bobbins that
are divided into two sections. You saw the bottom section off so you
can use just half the pot core. Yeah, it's a special part, but not too
bad to make. If you need a lot of them a custom coil place will be
happy to crank out as many as you need. In fact you could have a
custom coil place just make small coils that fit the core halves and
just pot them and sand the open end flat. Pretty cheap I think.

You could use two ferrite rod antennas or even air core but you'll
generate fields and emi all over the place. Pot cores keep things
under control.

Benj
 
J

Joerg

Jan 1, 1970
0
CWatters said:
Just makes the head vibrate. It feels very odd for the first two weeks.
After that it feels strange when I have to use an ordinary brush and teeth
don't feel as clean either.
Yes. It's not really "ultrasonic" but works. Thing is, where there used
to be micro-boulders coming off during the cleaning sessions at the
dentist this became a lot less so.

Hint for new users: Keep your mouth mostly shut while using it or you'll
spend the next 15 minutes cleaning the mirror ;-)
 
K

Klaus Kragelund

Jan 1, 1970
0
True. Signals are pretty easy to get across if it doesn't have to
transfer anything with the bandwidth and dynamic range of a Mozart
concerto. And even then there is 40.68MHz. For mundane stuff I like to
mux the signal into the power path to save cost.

What's the input voltage range and available primary current on this
product? I think there should be a way to do that power transfer on ISM
and save the core. At the quantities you were writing about it looks
like the core adds too much cost. Not just the ferrite but it's a manual
operation to place and pot them in. Unless it's in the tens of million
units where you could build a custom robot for that.

--
Regards, Joerg

http://www.analogconsultants.com- Skjul tekst i anførselstegn -

- Vis tekst i anførselstegn -

On this particular product the input is 115V single phase ac 60Hz, but
to be versatile it should accecpt 230V 50Hz also

So what you driving at is to make a DIY power line modem? - signalling
on the mains wires? It would have to be a capacitive coupling since
adding a current transfomer would cost as much as the other dual core
solution - or even more.

It would be a solution that should work on any power line
impedance....

Regards

Klaus
 
J

Joerg

Jan 1, 1970
0
Klaus said:
On this particular product the input is 115V single phase ac 60Hz, but
to be versatile it should accecpt 230V 50Hz also

So what you driving at is to make a DIY power line modem? - signalling
on the mains wires? It would have to be a capacitive coupling since
adding a current transfomer would cost as much as the other dual core
solution - or even more.

Ok, didn't know that. I thought it would be the usual drop resistor ->
rectifier -> zener deal from 230VAC down to some lower DC level and the
signal was to be used locally on the primary side. X10 devices often
work that way. What looks like a transformer in there is just a signal
coupler and the mains voltage is current limited and rectified.

It would be a solution that should work on any power line
impedance....

That can be done as well. What would be the data rate and where would
that signal be received? Even the rather crude and IMHO unreliable X10
powerline control reaches from one end of our house to the other. The
only reason why it fails on some of the wall outlet modules is that the
receivers have the sensitivity of a doorknob and the filters are like
open barn doors. So any EMI-filtered device or power strip reduces the
SNR and the energy-saver lightbulbs add a lot of RF-hash into the game.
In the end it's all a matter of selectivity in the filter. Also, it
should not be a simple AM protocol like X10. FM oder in this case
probably FSK would be much better. For good noise immunity the receiver
would have to be gated so it only receives around the zero crossings.
 
J

joseph2k

Jan 1, 1970
0
Joerg said:
I was a big skeptic regarding electric brushes. Until I used one. It
does clean a whole lot better. Also, since then the dentist doesn't find
any serious mineral buildups near the gum line anymore.

A long time ago we had a brainstorm session at a med ultrasound company,
to come up with product ideas. The sky was the limit. So we gathered in
little groups and ours had on its list, you guessed it, an ultrasonic
toothbrush. Laughing was prohibited but the guys were rolling on the
floor holding their bellies. Needless to say we left the stage like wet
dogs. A few years later Philips built one and still makes oodles of
money. We could all be on our own islands now :-(
I wondered who had the patents locked up.
 
M

Michael A. Terrell

Jan 1, 1970
0
John said:
I met Rich at a conference in Long Beach, and he's OK, except for
having the bad taste to be so tall.

John


I take it that you've never received one of his long, rambling,
drunken e-mails? :(

He was a lot different when I first encountered him on a newsgroup,
but something changed him. I currently have 16 kill filters for his
split personality.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
R

Rich Grise

Jan 1, 1970
0
What do you expect? He is Fred's twin.

I met Rich at a conference in Long Beach, and he's OK, except for having
the bad taste to be so tall.
[/QUOTE]

Thanks, John, but I just ignore Jim and Michael, since their opinions
have no value. ;-)

Actually, from a certain point of view, their hatred feels like high
praise! ;-D

Cheers!
Rich
 
Top