I've got my push-button ignition "proof of concept" done.
The code needed some tweaking, as well as delays and maximum distance the beacon can be away from the ESP32, and it still might need more, but I've got it pretty honed in, I think. Also had to use a different relay than I initially bought for this project. My next step is to get it into a project box.
It works like this.
I have a buck converter that will accept a variable voltage input (9v-36v) from the Goblin. I have not yet determined whether that power will be supplied all the time, or whether a kill switch will need to be toggled on (it will depend on the final current draw of this apparatus). That buck converter drops the voltage down to 5v, and sends output to both a positive and negative pair, as well as a USB port. The USB port will be used for device charging. The pos/neg pair runs to the power input pins on the ESP32, and to the power input on a dual relay module. I/O pins on the ESP32 are connected to those two relays for triggering. One of the relays then connects to the LED in my momentary push-button, and the other relay connects the actual push-button switch to a green LED behind a 330-ohm resistor. Finally, both the green LED, and the red LED in the push-button, connect back to the pos/neg pair on the buck converter. Whew.
The ESP32 module is programmed to detect the proximity of a BLE beacon (in my case, an Innway card). Here it is, without the card anywhere nearby. The red LED on the buck converter and the ESP32, plus the green LED on the relay module, indicate they have power.
Here it is, with the Innway card in close proximity. The LED on the push-button comes on, and the switch itself becomes active. (I added a 30-second delay for the card being removed from proximity before the relays shut off). A kill switch will need to be flipped to put the ignition in the "On" position.
And here it is with the button being pressed. The green LED is just a placeholder for the starter cranking. Naturally, if the card is not in close enough proximity, the push-button does nothing and the green LED doesn't light.
This probably is not the MOST secure system out there, but I think it'll be good enough to prevent any casual theft.
I believe I am going to add a third relay that will be used to only allow the ignition to be "On" while the card is in range. Actually, scratch that last bit. I'm only going to need two relays, I think.