(somehow certain discussion here seem to be counter productive)
I don't mean to offend anyone, but could we start some new threads on this topic? (or possibly a subforum?) This thread (IMHO
) should be sticking to the design and development of dfabro's circuit or others operating in a similar manner. All this development of knock detection with microcontrollers and IC's designed for detecting knock is wonderful and (again, IMHO) the future of MS knock detection however, this thread has been led somewhat astray from the origional topic. I'm afraid that the progression of all these great ideas is confusing some people. dfabro had a great concept of a circuit that we could all build with cheap parts that are available locally and it seems that for those who need knock detection ASAP, this is a superb solution. (Of course, I mean no offense to Boris. He sells a great product but its not in the MS budget for a some of us)
Anywho, I pulled up my schem and layout (modified dfabro's passive filter schem) from page 2 and I realized that the pinout of the npn trannies were backwards in my version of eagle
. It took a lot of time to identify that fault. Pins 1 and 3 need to be swapped i.e. flip the transistors around 180*. I also neglected to add pads and labels to the layout for certain things. I have corrected the transistor orientation on my prototype so hopefully I can turn on the tacho pin and test it today. If it does happen to work then expect a full updated layout with schem and notes and pics.