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Op-Amp buffered "hall" type sensor inputs 
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1N4001 - Signed up
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I see octoparts has many hits for that Lucas number, many sound about right on a brief description like Analog devices op-amp Digikey number OP177GS-ND

Do you know how close any of those are?


Tue Aug 26, 2008 9:38 pm
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I don't like those since there are trims all over it - more wasted pins, wasted space, etc.
Also, the TL082CN is something like 4MHz vs 600KHz, perhaps the slower chip is more noise resistant, though? It asks for 6V supply though I've been giving mine 5. So for half the pin count and the fact I know it works fine in the field, I'd skip the science project (for now) and just throw them on.

Digikey number: 497-2213-5-ND - one per board. (SMD would be fine, too)

Though of course, if people want to talk about the potential benefits of another chip, I would be open to it. I'm wondering if the gate delay is proportional to the max chip bandwidth. I wouldn't want to start missing teeth (on the miata they are only a degree or two wide) - basically at 10krpm I think that other chip would miss a 1 degree wide tooth. Not to say anyone would want to run a miata motor to 10 k, least of all on stock sensors, but it's a data point.


Tue Aug 26, 2008 11:00 pm
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Pretty unrelated:
1) Does anyone know how to edit footprints in KiCAD? I want to make a new one for this OEM connector
2) I had a design I made on my windows box, brought it over to linux, and wants to have "transistors.lib" which my linux install doesn't have. Any idea? Is it just a difference between versions?


Tue Aug 26, 2008 11:05 pm
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I would like to add my support in saying I like this circuit and I think it should be included in the main board. I particularly like the simplicity and adjustability of the circuit.

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Wed Aug 27, 2008 12:43 am
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ca7 wrote:
I would like to add my support in saying I like this circuit and I think it should be included in the main board. I particularly like the simplicity and adjustability of the circuit.

It's so simple it's just a Schmitt Trigger

http://en.wikipedia.org/wiki/Schmitt_trigger

How novel!

All sarcasm aside, it's a great idea. The only question I have is...why not just use a standard Schmitt trigger? The delay is going to be inherent in any sort of transistor-based IC. It's just gate propagation delay. In the same space as this circuit, multiple digital I/O lines could be buffered by a Schmitt IC.

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Wed Aug 27, 2008 1:58 am
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8InchesFlacid wrote:
1) Does anyone know how to edit footprints in KiCAD? I want to make a new one for this OEM connector

I'll bring this up in the layout thread.


Wed Aug 27, 2008 2:03 am
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thebigmacd wrote:
ca7 wrote:
I would like to add my support in saying I like this circuit and I think it should be included in the main board. I particularly like the simplicity and adjustability of the circuit.

It's so simple it's just a Schmitt Trigger

http://en.wikipedia.org/wiki/Schmitt_trigger

How novel!

All sarcasm aside, it's a great idea. The only question I have is...why not just use a standard Schmitt trigger? The delay is going to be inherent in any sort of transistor-based IC. It's just gate propagation delay. In the same space as this circuit, multiple digital I/O lines could be buffered by a Schmitt IC.

Heh, a term I've been familiar with for a long time, but haven't put a function to. Yes, that's exactly what I'm looking for - I wonder why Mazda did it the other way? Perhaps the general schmitts they found were too fast? In general I found them to be overzealous about noise avoidance in that circuit, then again, the car never skipped. :-)


Wed Aug 27, 2008 7:16 am
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thebigmacd wrote:
It's so simple it's just a Schmitt Trigger

Yep. :mrgreen:

thebigmacd wrote:
The only question I have is...why not just use a standard Schmitt trigger?

I like it because you can adjust the hysteresis thresholds to suit the application.

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Wed Aug 27, 2008 8:29 am
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