you want regulators anyway because voltage fluctuations can have an adverse effect on logic circuits. if you can, test your circuit while varying the supply voltage. make sure a changing supply voltage doesn't cause a circuit to change state.

do you drop again to 5V for the logic? can you get buy with just 5V for everything? that works out well for both a diode and a voltage regulator. a fuse is also a good idea - better to pop a fuse than burn out a trace

 

The regulator drops to 8 volts for the entire circuit. The minimum needed to hold a steady 8 volts is 10.5 volts. I figure since that is extreme voltage drop for a car, it should be ok. Would you suggest dropping even further to a 5 volt regulator? The 4000 series chips work on 3v to 18v so that shouldnt be an issue.

 

8 volt is probably fine. i didn't know if your IC's needed 5V or not.

 

Cool. Everything's wired up besides the relays. After thinking about the relays more, I realized that the 5v output and low current from the ic's are not going to be nearly enough to trip the relay. I'm almost certainly going to need to run them through a transistor. I still want to use the relay since I think it will be more rugged than a bjt or MOSFET, but I'll need one to get to the switching voltage. I was looking through the maintenance manual and it seems like the starter wire is a 50A max, but the ignition wire doesnt seem to have a fuse or relay connected to it. I have no idea what the current rating will be and how strong of a relay to get for it. Below is a picture of the diagram I'm getting all this from.



The wire coloring is here

 

So I got the whole thing working in the car today. I will put up a video as soon as I put the car back together. Thanks for helping me out throughout the whole process. I don't think it would have worked as flawlessly otherwise

 

excellent project and congrats! it's great to have an idea come together. did you end up using a transistor to control the relay? i'll usually just have the output from the circuit come into the base then let the collector-emitter path switch the relay coil to ground.

 

Haha, that's exactly what I did. I used the tip120 npn darlington to flip all the relays. This was my first all analog project. Every project I do I decided to use microcontrollers to control everything. Thank you for all your help. I almost have everything back in the car so expect a video soon.

 

Quick video of the push button start. I want to thank keep_hope_alive for all the help

Push button video

 

excellent work. very cool project. nice start button.

my input would be to not have the presence of the transponder immediately turn on ignition/accessory power, but instead to have that enable the ability to turn on ignition/accessory power - such as the button up top you use for shutdown.

starting would be placing the transponder in range, enabling the ignition/accessory, then pushing start.

you should add to the video what happens if the car is in gear, or if the brake needs to be applied, etc.

i agree having an accessory only option would also be nice - so radio on without ignition on.

overall, awesome job.

and yes, i do like the interior work.