Things got a bit delayed because I wanted to understand completely the circuits that are available, then determine which one to use. Turns out the ready made circuits that are out there are not to my liking. There are two finalists and the first one uses non-automotive thermistor and low ohm values that lead to more failures over time. The other one uses the proper values, but still non-automotive thermistor. Then, to top it off, it is not expandable. I want to add a few things to my circuit, so this means re-learning everything I forgot about electronics years ago. It has been a lot of fun and I am really getting into it.
The circuit I am designing from scratch uses 20 amp relays, automotive grade thermistor, a dual IC Comparator that gives me a second Comparator for expansion, and feedback/hysteresis protection. This route enables me to add the last feature I will include in the Basic system, Low Fuel Warning. So the Basic system will have a Charging System Light, Oil Pressure Light/Audible, Water Temperature Light/Audible, and Low Fuel Warning Light. I will offer it customized for each person's desires. Of course all of the plans to make it yourself will be available first.
The rest of it is pretty much complete, but the low fuel warning is in the works now. It will include the ability for the user to adjust where they want to see a low fuel warning. Since it uses the fuel sender, we will be able to adjust it anywhere from almost full to less than empty! It's a bit tricky working with low ohm values like the fuel sender (0-30 ohms), but this has been a real education and something I really enjoy doing. Thanks to everyone who has been encouraging, and to those for actively helping. It's coming soon, but I want to get this right.
