Thanks to some very expert help here, I was able to overcome a few deficiencies in my training and complete the basic circuit. Special thanks to MarcF and MikeML for really helping me move forward. It is a complex project for me and something I simply couldnt do without expert input. The question now is, does this circuit look ready for a production run of actual printed circuit boards, or is there more tweaking to do? It works exactly as advertised right now, but I am hoping for a review. The schematic for the entire board is the last file.

 

Thanks to some very expert help here, I was able to overcome a few deficiencies in my training and complete the basic circuit. Special thanks to MarcF and MikeML for really helping me move forward. It is a complex project for me and something I simply couldnt do without expert input. The question now is, does this circuit look ready for a production run of actual printed circuit boards, or is there more tweaking to do? It works exactly as advertised right now, but I am hoping for a review. The schematic for the entire board is the last file.

Nope. Automotive is prone to vibrations and the screw connectors tend to eventually crack the wires - not a great idea. It would be better to add permanent connections and some sort of strain relief on the box and an OEM connector so the end user can just plug in.

 

The current circuit configuration is a mockup so that it's understood that things like LED's, Thermistors, Piezo buzzers will be separate from the board itself. Once it is in Diptrace, there will just be pads for those items so I can solder the leads on. The help I am seeking is proofing the circuit to make sure I am using acceptable circuit logic. This is a not for profit operation, so having professional boards made up is something that I can only afford to do once if I am lucky. I cannot make any mistakes and hopefully with the professionalism here, I won't.

The two wires in the low fuel circuit that are not connected was a printing error.

 

I am making very good progress with Diptrace and am well under the number of pins so the Freeware version will work for this project. It has its nuances, but I have my prototype board ready for Gerber files, EXCEPT..

1) Are relays normally shown Energized or De-Energized? Rookie question for a Rookie.
2) Same question for relay data sheet diagrams. for example, is the picture of the SRA-12VDC-CL
shown here: http://datasheet-pdf.com/datasheet-download.php?id=807655 shown energized or de-energized.

THANKS!! I want to get this right.

 

Hello,

The relays are normaly shown in de-energized mode.
The NC contact is Normaly Closed and the NO contact is Normaly Open.
The third is tne COM Common connection.

Bertus

 

Thank you Bertus. Great! So, I am at the point now where Diptrace is going well so I will be getting flat boards with everything in the right place for a solderable board. What about connectors? I have 8, 2 pin (5.08mm) connections off board to make, and one main header that is 12 pins (5.08mm apart) that go off the board to make. Here is the diptrace capture. The question is, on a vintage 30's thru about 80's vintage vehicle, with this board in an enclosure, what is the appropriate accepted connectors to use? For even more information on this project, here is the link:

http://devestechnet.com/Home/WarningSystem

My hope is to make this public domain information so everyone can benefit for free. I will make them for people who do not have the expertise for a price to keep the website updated, but for the most part, its a retirement project that I want to do RIGHT. Thanks!