Closed Loop Monitor [Archive] - M42club.com - Home of the BMW E30/E36 318i/iS
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mrjezza
06-20-2006, 08:29 PM
http://autospeed.drive.com.au/cms/A_1716/article.html

Does anyone know how one of these works (read: how I can make one without subscribing to that website ;))?
john318isau
06-20-2006, 08:49 PM
If you click the Print Article link (http://autospeed.drive.com.au/cms/A_1716/printArticle.html) you get some small photos from which you can probably work out the wiring.
john318isau
06-20-2006, 09:48 PM
...and the photos are pretty easy to access too if you know what to look for:
mrjezza
06-21-2006, 03:06 AM
Legend :) I initially tried to access the pages by typing in page names manually but that didn't work so it never occurred to me it would for the images.

Well done ;)
bmwman91
06-21-2006, 12:41 PM
So....it looks to see if the O2 output keeps bouncing above & below .45V (closed loop) vs. going consistently higher (richer at WOT & open-loop)?

The LM311 is a voltage comparator...and I guess the pot sets the O2 output threshold at which the LED gets turned on? Pretty nifty simple little device. For under $10 I would say it is worth it for tinkering enjoyment.