Reddit mentions of Qianson DC 5V 12V 24V Digital LED Display Infinite Cycle Delay Timer Switch ON/OFF Relay Module (DC 12V)

Well I super appreciate your help, I just don't want to burn my house down lol If you think this is doable then I'm totally for it, as to me it feels like smarthome equipment would be major overkill for a function as seemingly simple as this, which is why I posted here originally.

Here's what I have right now, the plug kit for the LED strip light plugs into 110v and has a transformer that steps it down to 12V 3A. The transformer has a male DC barrel jack connector that plugs into a female barrel jack connector that's already wired to the LED strip lighting. My idea was to get some 2 wire barrel jack connectors (male and female) and create a sort of inline dongle, with whatever I need in the middle of that to make this operate. Doesn't even need to be a reed switch, as I suppose I could get away with doing this with a motion sensor as well, I just need to somehow control the light when the door is open.

Any help you're willing to provide would be greatly appreciated. Like I said, I am a PC tech but I don't have much experience with wiring diagrams or individual electronic components. I can solder two wires together though lol

EDIT: Hey I just found this with a quick amazon search for 12v inline motion sensor: https://www.amazon.ca/Pooqdo-Automatic-12V-24V-Infrared-Motion/dp/B00YA7O5TG/ref=sr_1_fkmr2_1?s=hi&ie=UTF8&qid=1484606596&sr=1-1-fkmr2&keywords=inline+12v+motion+sensor

Then I'd cut the switch part out of this and wire in the aformentioned motion sensor: https://www.amazon.ca/5-5x2-1mm-Connector-Switch-Black-Single/dp/B00KHSJ9KM/ref=pd_sim_201_5?_encoding=UTF8&psc=1&refRID=Y8W9D5SXNNRJPC0WS2NS

Given my description above, would this work as I described???

I've also found this item...not sure if this is something I could use? https://www.amazon.ca/Qianson-Digital-Display-Infinite-Switch/dp/B01LVXEU3M/ref=pd_sbs_469_7?_encoding=UTF8&psc=1&refRID=22KDPMN1HPY3BD83VD9G

Try this: https://smile.amazon.com/HiLetgo-Switch-Adjustable-Module-Second/dp/B01DK8NJNI

This might actually work better: https://smile.amazon.com/Adjustable-Switch-Module-Trigger-0-25Seconds/dp/B07DGRQMBM

How you'd want to do it is have the Meross trigger relay feed this device 12v to power it. Don't use the trigger option of this device or it'll actually get more complicated (and potentially open your garage door if the power goes out).

If you wanna go real crazy this is also an option: https://smile.amazon.com/Qianson-Digital-Display-Infinite-Switch/dp/B01LVXEU3M

Ya know, I just saw it does 9v-15v input on it's 12v power input. That is quite a range of voltage to power this, perfectly in-line with a car's 12v (typically 13.5-14.2 @ idle, 12.5-12.1 @ off).

I suppose one could use a simple 2020 (20v20a) spst switch mounted to the dash to turn power on/off to this system, of which it could be mounted anywhere such as the engine bay, glove box (though pref not), under the dash (pref not again), etc.

The only problem is that it could potentially drain a car's battery flat if you forget to toggle it off.

Let's see... I have a 55Ah 20hr rate car battery which is AGM and can discharge to 40% safely. So that could easily do 15-20 watts for a day (semi-high idle load of the Lattapanda, my high end estimation). So what that easily covers leaving the mini-PC on overnight, possibly even 2 days, that'll cut it really close.

BUT..... We have things called timed relay switches. I could easily wire in a timed relay switch that auto-engages and turns off after 10 hours. EG: https://www.amazon.com/Qianson-Digital-Display-Infinite-Switch/dp/B01LVXEU3M/ref=pd_lpo_vtph_469_lp_t_2?_encoding=UTF8&psc=1&refRID=4NN1ZT6Q0N6SSKNCCMZK

So you flip a switch on, which powers the relay, which then starts a timer and powers the mini-PC for 10 hours.

Then, after 10 hours, poof, power cut. That would actually work!

HOWEVER....

My vehicle easily has room for a second battery. Not a full truck size battery, but the size of a light passenger vehicle for sure.

I could wire my car's power like this:

Alternator ---> Relay block
Relay block ---> Main car battery (at all times)
--> Isolator to Second car battery (only when accessory has +volt aka car is on)

So when the car is running, it charges second battery. When car is off, the second battery is physically disconnected from the main car battery. In other words, you can never wear out the main car battery. SAFETY!

THEN.... I can draw a small fusebox from the second car battery and patch in the LattePanda directly to that. And more. For example:

Second Car Battery ---> New Fuse Box
New Fuse Box ---> Relay to 3 front-mount switch #1 and #2

-#1 Front Mount Switch (ON) --> Turns 12 power to the LattePanda

-#2 Front Mount Switch (ON) --> Enables power to a nice 100w USB hub (powers multiple devices in the car)

Also, my vehicle already has a 400watt AC power inverter. It current requires the engine to be running, however, I could remove the requirement for an accessory power to enable it to be turned on (thereby allowing it when vehicle is off) and then rewire it to use the second battery.

I could probably also wire in the car stereo to use this new battery, too! This would be a bit different since I am guessing the stereo has an always-on low power connection (to maintain radio saved settings and such) as well as an accessory power relay for fully turning on the stereo. What I could probably do is wire the stereo's main power to flat out use the new battery, and then create an accessory power false on switch. This switch, when toggled, when provide a +volt to the accessory relay, making the stereo think the car is turned on when it is not. Since it is powered by the secondary battery, no issues with draining the main to 0.

POOF!!!

• Now I have a full car computer, running off isolated power battery with no worry about draining my main car battery.
  
• Plus full AC power inside vehicle when auto is off.
  
• Plus full USB power ports in vehicle when power is off.
  
• Plus full car stereo when power is off.
  
  BUT WHY?
  
  Err... I dunno. Play video games while @ Starbucks?