My house is equipped with hard-wired 24V buttons connected to a pulse relay (teleruptor) who toggles on and off the 230V (one pulse on, next pulse off). I managed to integrate them in HA using the procedure described by @francisp in Hassio combined with hard wired switches
Now I want to go 1 step further by using 1 of these buttons to trigger an action in HA, for example turn of all lights. I don’t want to replace the buttons with smart switches because everything is nicely integrated in the room and I wan’t to keep it that way.
So is there a device that can recognize the 24V pulse and activate something in HA/Node Red.
Everything I find (like a Sonoff Mini) is rated for 3 or 5V
thanks in advance
You could use a buck converter from 24V to 3V. Then connect the 5V end to a ESP. Works for me in a different kind of setup
Edit: it’s a 24V to 3v converter
You might look at the Shelly line of products:
Their Uni device is tolerant of AC and DC ‘low voltage’ up to 24V and 36V
The Shelly 1 supports DC up to 60V
and others
Their products are pretty flexible in ways people use them, non traditional.
Do not connect 5v to the esp. They are 3.3v.
And use an optoisolator rather than a buck convertor.
Sorry my bad, using a 24V to 3V buck converter
That’s probably not true. All evidence (anecdotal and factual) seems to say that the ESP8266 is 5v tolerant on the GPIO pins.
A reading on the ESP8266 datasheed shows that the I/O pins are protected for voltages up to 6Volts, (https://cdn-shop.adafruit.com/product-files/2471/0A-ESP8266__Datasheet__EN_v4.3.pdf) at the bottom of the page 17) so connecting it to a +5V output should not be a problem.
All digital IO pins are protected from over-voltage with a snap-back circuit connected between the
pad and ground. The snap back voltage is typically about 6V, and the holding voltage is 5.8V. This provides protection from over-voltages and ESD.
The Vih Max of the GPIO pins is 3.3v, means that the manufacturer absolutely guarantee that the chip will understand a voltage of 3.3V and up as a HIGH level. Vil and Vih are the voltage limits for the chip to recognize the LOW and HIGH levels respectively and not maximum ratings.
And probably the manufacturer implemented a snap back rather than the ESD diodes to ease the interface with 5Volt systems without series resistors or intermediary devices.
However, what’s listed in the datasheet in section 2.2 is the normal operating conditions, not to be confused with (the missing) Absolute Maximum Electrical specs.
However the most damming evidence is that all the way back in 2016 Espressif CEO Mr Teo Swee Ann commented
“I can reply officially here: it is 5V tolerant at the IO. while the supply voltage is at 3.3V.”
Other sources:
I have read some articles before. There are those who say that ‘while 5v may work, it’ll stress your system and you may break it.’
It is very hard to know the truth here, but it seems to me thta sticking to 3.3v is safest, although perhaps overly protective.