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Old 03-09-2011, 10:05 AM   #5 (permalink)
dcb
needs more cowbell
 
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I don't know about "much" safer, or even safer at all. The signal has to go through a 50k resistor before it even sees the zener/CPU on the mpguino.

Many times people use optoisolators (and other things) dogmatically, even though driving that internal LED to a useful level can be more load on the circuit being monitored than a much simpler arrangement (i.e. resistor/zener).

Additionally optoisolators can introduce different asymmetric delays, depending component/manufacturer/circuit. So the table of car settings might not be valid with such modifications.

So with no hint of more "protection", plus signal drain, and guaranteed costs and complexities with optoisolators, what is it we are trying to make safe? The CPU? Millions of people spend more on a latte every day than the cpu costs.

re name: I'd rather be able to discern between homemade guinos and the "official" design (or variant designs), so call it the bobguino I guess Something that will distinguish in normal conversation, mpgshield?
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Last edited by dcb; 03-09-2011 at 10:15 AM..
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