Alain Turbide

Excellent analysis . I like the idea of pre-biasing the base of the optocoupler transistor. I'll try that out. I couldnt do that with the tlp521 as it does not...

I really don't have the resources at this time to maintain it and have not seen any real requests for more info then what is already available. It's a fairly...

https://www.amazon.ca/Converter-Module-Keenso-Step-Down-Conversion/dp/B07PQLNXVC/ref=sr_1_26?dchild=1&keywords=step+down+mini&qid=1615644230&sr=8-26 or any lm2596 based regulator https://www.amazon.ca/Converter-Ajustable-Step-down-Converters-1-25V-35V/dp/B074J4DLWQ/ref=asc_df_B074J4DLWQ/?tag=googleshopc0c-20&linkCode=df0&hvadid=335365451913&hvpos=&hvnetw=g&hvrand=1334836585404895701&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9000757&hvtargid=pla-899437512675&psc=1 Both of those work extremely well. None of the parts are critical. Any inexpensive optocoupler will work. Same goes with the esp module....

Sure, I think it would work perfectly

If you can't send keys that means your tx circuit is not working. Looking at your circuit soldering, the optocoupler looks to be miswired. It looks like your are bridging...

Looking at the soldering, they do look soldered together. only pins 2 and 3 go to ground. 

Arm /disarm/send a key. You should see a logged response on the esphome log window.

If i were you I would double check the pinout on the 817 . The wiring is all wrong from what I see. https://www.twinschip.com/PC817-Optocoupler

Yes, that's correct but on the picture pin2 is going direct to the esp module? I don't get it? That should be ground

ah ok.. I see now. The solder on the underside threw me off also.