I may change bleeder resistors from 2k to 1k to speed up the transition.

Atoto needs maybe about couple hundred milliseconds voltage drop to lock in a status change and execute a function.
Discharged 220uf cap looks like a dead short for a small amount of time, creating the voltage drop on the SWC wire.
When cap charges up all current flow stops, and the command event is finished.

To program SWC (steering wheel control function of live rear view and back), short caps 220uf leads together.
Then run the SWC function assignment in Atoto on screen display SWC programming.

SWC circuits use voltage drop measurements on a wire that the Android Atoto head unit then fire off an android program or function.

220uf caps bleed down so when SWC 5v+ power enters the relays, the caps quick charge up and Atoto sees a voltage drop and executes the function.

This circuit uses a continuous 12v+ source to turn it into a momentary trigger. Resistance values 1K and 2K create voltage drop on Atoto SWC wire.

What this does for me, I can select rear or side cam on my rocker swtich, Atoto will load live rear view app and sho the camera stream without parking grid lines. Put rocker back to center, power shuts off , and the back function is run on Atoto displaying the prior screen.

Also when I select right turn signal, same idea happens, live rear view shows side camera, turn off right turn signal, atoto executes the back command.

The 100uf cap is a keep alive cap for relay 1 to continue to send SWC power to second relay long enough for relay 2 to allow the status change.
SWC relay 1 completely disconnects SWC wire when 12v+ goes away, otherwise there would be a continual voltage drop on the SWC wire.
Eventually I plan to wire this up, do you think it will work.

 

I bought a five pack of toggle handle DPDT switches 0n/0ff/0n for $7.86 reduced on Amazon for the project.
I was thinking use a switch to program Atoto with resistors, don't mess with shorting caps, etc.... the logic was getting too convoluted to try to mod circuit for programming Atoto.

This way put SWC wire on switch center, and resistors to ground. Turn switch on one way to program back command. Throw switch other way to program to run LRV command. DPDT were cheap and give me more options for other projects.

 

I gave it a try, but could not figure out using those relays. I bought 2 programmable boards.

Relays are interlocked, keeps the bottom relay off until top relay turns off, otherwise Atoto wont get a clean signal.

SWC wire goes into top relay
SWC wires run to ground, 2k ohms for camera on (live rear view), 1k ohms for back command, as in go back to previous screen.
ACC+ is yellow on the left
yellow with red is the rocker switch and right turn signal on. Has 1n4002 diodes to prevent backfeeding.

Program will be,

top board, P1.1 for when trigger is there, relay powers on 0.5s
bottom board P4 for when trigger is gone, relay powers on for 0.5s

 

copper jumper soldered in for common trigger and power ground

 

mounted in truck, and it works!

The toggle are switch above top board is set for programming the 2k and 1k functions, 2k for live rear view, and 1k for back command.

The boards automate this for right turn signal, show the side cam, turn off turn signal, go back to prior screen
And same for my manual rocker on/off/on switch to show the rear or side cam continually. Then turn off rocker, atoto goes back to prior screen

 

Evolving improvement. I returned those boards as they did not have a low level trigger. I found out if you lock the SWC 'button', (a relay here), DOWN, the Atoto can not accept anymore SWC commands. I was running P4 on both of those boards, one at 0.9s, one at 0.4s

Looked around and bought the DROK relay board. 2.56vdc+ exists on the low level trigger terminal, when that goes to ground, the board programming runs the relay. P1 and 0.5s, ground LTRIG, relay fires on for 0.5s then off. works perfect. Now no more hold the relay on like other boards did. I wired a 5 pin automotive relay to invert the signal from my acc+ rocker camera switch so as to cause a ground path when I turn off the camera, which then fires the relay and Atoto runs the back command to show the prior app view. So turn cam on, top board runs Live Rear View command, camera image appears, turn off rocker switch, bottom board senses low trigger grounded and the prior screen appears.

While it is working great, I am thinking I don't like hearing a clicking relay, they are pretty loud.

Means use a P Channel Mosfet like NDP6020P with a very low voltage threshold to create a ground path when my camera rocker switch turns off. Acc+ coming from rocker switch. Got 10 mosfets from AliExpress for $3



here are new boards, inversion relay dangling loose for now. These are from Amazon and easier to program
I kept the relay interlock. That actually causes Board2 to fire relay when powered up, but does not matter as Atoto is still booting when ignition comes on

Board is powered by ACC+, rocker sends ACC+ to top board HTrig.
SWC with 1k and 2k resistor wires are on the relay side.
Program toggle switch partially hidden, needed to assign function resistance value to Atoto SWC programming menu.

Green circled relay eventually replaced by the mosfet is my goal, lot smaller and quiet.


DROK programmable timer board with high and low triggers, very nice.
https://www.amazon.com/dp/B0CPY6ZJ48?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1