Hi, The power supply is going to cause great problems in an automotive design. First off, your design should handle "load dump" (google it). Your regulators are only good for 29volt input and in an automotive system there are situations that can greatly exceed that limit. You will need some type of suppressor circuit. Second, it would be nice to have some sort of common mode choke in the supply to remove noise. A fuse would be nice as well. The 12V supply regulator won't have enough headroom when the ignition is off, or when a transient occurs (like lights being turned on). You may want to search around the net and look for good examples of automotive power supply designs. I didn't check the rest of the schematic. Ken klumia@adelphia.net ----- Original Message ----- From: "Milosz Kardasinski" To: "Microcontroller discussion list - Public." Sent: Monday, January 31, 2005 7:44 PM Subject: [EE] Critique my project schematics > Hi guys, this is my first pic project and I'm hoping that some of you > would be kind enough to review my schematics for mistakes and blunders > and offer suggestions as you see fit. I don't have a background in EE > so this is designed with knowledge obtained from the list, internet > and some old electronics books. > > http://www.geocities.com/mr_goat2000/schem.gif > > The intent of this device is to control an electronic transmission. > There are inputs from a pressure sensor, thermistor and 6 switches as > well as the LM1815 chip which is meant for a variable reluctance > sensor. Outputs are to solenoids and the LM7221 which controls a 4 > digit led display. > > I have USART for debugging and possibly a bootloader in the distant > future. > > Do I have adequate decoupling for the automotive environment? Any > other comments, suggestions are welcome. > > Cheers, > Milosz K. > -------------------------------------------------------------------------------- > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist