wiegand wire

and the 'optical' material, too? what's that application?

watching a spinning magnet through an aluminum wall. peek field strength at the sensor in the 80-120 Gauss range. Something completely passive and generating its own voltage signal is exactly what i was looking for. no DC source power required, not ESD sensitive.

You read engrish?

What on earth was that supposed to mean? It was a sensible question, and you've posted a remarkably stupid response, even for you.

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Bill Sloman, Sydney

If you read the first link, you'd see some Engrish like :

"The mainly features is it?s needn?t power supply when it works"

and other comical bad English. Geez, this thing appears to be a coil of wire built into a component package. I suspect many applications can be accomplished with plain copper wire coils, without the Weigand effect.

Jon

Being rude to Mook Johnson because he provided links to Chinese suppliers does strike me as irrational and unnecessary.

Clearly you don't understand what the Wiegand effect does. There's a significant difference between a voltage that is proportional to the rate of change of magnetic field, and a voltage spike that appears as the local magnetic field crosses a threshold.

It's a cute effect, if rarely applicable.

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Bill Sloman, Sydney

Wiegand wires were once embedded in personnel identifier cards. At that time [circa 70's], very difficult to counterfeit compared to magstripe. We sold them to the military customers wanting that level of difficulty. [There is a possibility that some were sold to Australian customer] It is true the little pulses coming out of the reader were always about the same magnitude whether card was pulled fast or slow. Speed only changed the time between the spikes. looked like little 'pops' as you pulled a card through.

For what it's worth, the magstripe reader's output was a voltage waveform of pretty much constant area, so slow meant not very tall. Fastest speed I could get was 40 ips. Below 1 ips the signal tended to get lost.

The referred pages are written in mangled English, some parts do not make sense. I guess YOU do not understand English.

Why should Mook Johnson be criticised for referring us to manufacturer's product pages which were written in less than perfect English?

They were as comprehensible as we needed them to be. Was he supposed to correct them before he drew them to our attention?

I guess you don't understand that this usegroup is about electronics, rather than grammar.

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Bill Sloman, Sydney

Thats the exact reason why I'm looking for a US supplier. The halls and GMRs currently used are failing regularly due to the environment. No amount of potting, ESD ruggedizing or training has helped. Something like a dumb piece of wire that can output a pulse when a magnet pole passes and the amplitude of the signal is the same no matter how slow the magnets are moving (think flow meter) would be ideal.

Don't sweat it Bill. I knew what he talking about the poor English in the datasheet. However, despite the so-so translation, the datasheet is fairly comprehensive on describing the action of the devices.

please contact me offline with the first word, OFFLINE, added to whatever you wish as the subject. I may have a solution to what you're doing [I'd avoid hall effect and gmr's and stick with more 'passive' solutions to maintain the operation over very wide temp range.]

I once designed/invented a replacement for Hall Effect Sensors that were used in a 'pig'. Replacing 60 sensors per system. My solution required 2mA per sensor instead of 10mA the existing HE sensors took, was more accurate at a repeatable/stable 0.1% instead of 10% and did not have HE's wild tempco, being very much less temperature sensitive [operated over much wider range], AND cost was a wash. I also used a similar design inside a more effective card reader. The unique aspect was the voltage out of the 'head' circuit was proportional to B, not dB/dt, so whether you ran a card through the reader at 0.1 ips [which is EXTREMELY slow!] or ran it by at

20+ips the peaks of the waveforms were identical, so all the threshold detector had to do was normalize the signal [variation caused by initial field on card and the gap, which had a small variation too] and then cut that voltage in half to set the detection threshold - result was an extremely reliable card reader that performed over wider range of reader speed, a wider range of temp, and a wider range of card quality. Plus, was completely card compatible, to ANY card manufacturer, including really poor mfgr's who made cards with missing material. [apologies, this is starting to sound like spam, but I'm also an EMC Expert and present 4 hour seminar on subject called, "Designing for EMC" I once designed a TTL controller to replace relay logic in a 200kV 'inadvertantly discharging' environment using the principles/techniques presented in that seminar. The TTL Controller barely glitched during ESD events where historically in the same environment relays would often hang, or worse, be blown out] We should continue this discussion offline.

Right. I do understand what it does, and it may make an economical sensor in a number of low-cost situations, where you want a sharp pulse when the magnetic field changes, without a lot of signal conditioning circuitry. A number of times I've needed some kind of magnetic pickup and just hooked an old relay or solenoid coil to a scope input to measure RPM.

So, yes, if you DO have these Weigand devices at hand, they could be used, and could save a bunch of electronics. One place I could see it REALLY making sense is in a wake-up circuit that draws zero power when off. The Weigand device pulse could generate enough energy to turn on a FET.

Jon

Read your post on Google group, are you still interested in a supplier of Wiegand Wire?

Brian Wiegand Wire Consultant Brian Pulisciano snipped-for-privacy@snet.net

If you are interested in a supplier of Wiegand wire or sensors contact me.

We have made some positive improvement to the Wiegand output and process. The last manufacture HID wire was designed primary for their security cards. The cards did not require the output that sensor require. We have tweaked our wire specifically for sensor.

Wiegand consulted Brian Pulisciano snipped-for-privacy@snet.net