I was getting all excited about ordering all the parts I need to get to the finished design. Well, I realize there is more to it than just firing up Eagle, and laying out the board, ordering it, having a B.O.M. ready and assembling a couple proto boards.
I am needing a good solid proof of concept. Can I really measure C.H.T's and E.G.T's with the simple design, and a multiplexer? Well, lets try it and find out. Otherwise I need to build something different. Will the various analog inputs work with a Tack and other inputs? Well, lets get them other inputs working, and then try a tachometer.
For now, I am going to use at least one of the LTC1050s that I have for the CHT's. I'll just set it up like the example on page 9, the 500degree battery powered temperature sensor. If that is working, with reasonable accuracy, then I'll add a multiplexor in front of that. I'll probably need a different amplifier for the EGTs since they will get to something on the order of 1500degrees.
For the oil and fuel pressure senders, I have something like the The Mitchell 80# sender. This will ground some of the supplied voltage, and we need to measure the current going through the sender. We can do that with a transistor, and some resistors.
I've also got a hall effect current sensor that I want to use. I think it is an Allegro. I got it as a sample a couple years ago. I'll finally get to try that out. That is supposed to handle up to 100Amps with no shunt, all power is available.
The one worry I have is about board layout. I may have to look into getting another board, and modifying it (electronically). That is be beauty of open source, people share, and allow fixing things. People share, and make things available for the rest of us.
Anyway, you can see I am getting more active. A little success will do that for a guy.