oxygen sensors for aircraft

"You'd better stay away from 100LL then. The auto oxygen sensors will
be ruined by lead. The main reason is simplicity. No "computer" is
required. The EGT therocouble is about as simple as instrumentation
gets."

no computer required. check
http://www.autospeed.com/cms/article.html?&A=0959 and
http://www.autospeed.com/shop/category_579/browse.html (do a search on this
page for "Mixture Display Kit For Fuel Injected Cars")

set your mixture the way you always do, and note the meter or led
indication. next time you want to quickly set the mixture, all you have to
do is set to the same indication. i've found that when the oxygen sensor
gets contaminated by lead, it shows a false lean setting. so when it gets
to the point that it no longer shows on the meter, replace it with a used
one from the local auto repair shop - they normally throw them away.