Magnetic field of a solenoid

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.

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

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.

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!

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

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

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 ;-)

ne

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

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.

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.

I wondered who had the patents locked up.

What do you expect? He is Fred's twin.

-- 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

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

John

Use it to clean the taps :-)

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.

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