@turbo2ltr with a handle like that, and how active you are on the forum, I thought you would be “the car guy” to help out on this.
Firstly, apologies if my question should have been in “Support” rather than the “Projects” area. I suppose it is a little bit of both???
Thanks Mike, you have confirmed a few things ( assumptions ) for me:-
That this is a great community willing to help out others and share knowledge and experience.
I was also concerned about the latching relay drawing current, I have never used one, merely just aware of their existence. I was hoping that at a resting state in a Normally Open position it was mechanically held open. but I suppose this is more of a standard relay function. I guess it was just some wilful ignorance, I was actually trying to convince myself and ignore the fact that is how it works.
This also confirmed that my initial sketch I did, may have been closer to the answer, whereby I did use a standard automotive relay, with the thought ( and again hope ) that upon scanning the FOB it would energize the circuit/relay for as long as the fob was in range; so scan with one hand and open door with the other, stop scanning and the door auto re-locks. After scanning, I believe the Push to start stays active for 15 - 30 secs which should be plenty of time to get in and the car started.
I was also assuming/hoping that I could get this to work as a 2 in 1 system using only One RFID system. (Access AND Start (activate start/stop))
I have not yet been able to find out the FOBs operating frequency, but I will do this once it arrives.
( i might be in the market for another implant )
The claim is a read distance of 20-50mm, and I will do some testing through the car windows when the equipment arrives. The kit I purchased is the newer version with an 88mm reader rather than the 67mm so I’m assuming this will increase the gain and therefore my chances of a good read.
Re: positive or Negative switching I will find this out when I actually get the door panel off…
Thanks very much for the diagram, this will come in handy when the bench testing begins. and your idea will be the first setup I try.
Speaking of which, you have also planted a seed:-
I will do some measurements on current draw of the latching relay and I may isolate the latching relay system to run on its own battery with a Low Voltage Cut Out and connected to a VSR for charging. I’ll need to put a “hide a key” on the car as a backup…I’ll put some more thought into this.
Thanks again, and now the thinking and waiting begins.