faeibson
commented
2 years ago Hi,
that was exactly the scenario of my friend to be honest with whom I started that small project - he wanted to control his nine radiator fans in groups of three depending on water temperature via his PC or smart phone. Indeed you can just take the PWM signal to a splitter since it's just a digital signal, we did so too and tripled each of the control's fan ports. The RPM signal of the fans is not fed to the ESP by now anyway, but that could be integrated easily I think. We would just need one more IO pin for every fan port and then read the signal. Furthermore, of course it is possible to extend the control by some more fan ports as long as we have capable IO ports. The ESP8266 is very limited in that regard, only offering a few "true collision-free" IO pins. D4 and D5 could supply two more fan ports. Basically it should work to move the SCL/SDA pins from D1/D2 to D8 and TX and then we would have a total of 7 possible PWM outputs (D1 through D7) - however, no more pins for a hypothetical RPM reading. Maybe at some point it would be advisable to switch to another controller, e.g. the ESP32, providing a lot more IO pins and also more power.
The ESP already reports all the values and status via JSON. You would have to tell Home Assistant how to read that, just look into the RESTful sensor documentation: https://www.home-assistant.io/integrations/sensor.rest/ Never thought of that, I will tell my friend to try it out, too, since we're both using Home Assistant as well. 😃 I'll keep you updated with that. Obviously it would be really cool to control the ESP over REST, too, instead of only reading, so that one could just completely control their fans over HASS or any other interface of their choice and not necessarily via the ESP web interface. Maybe the user interface could be (should be?) decoupled completely... Hmm... Will have to think about that.
I will add the fan RPM reading and the HASS integration to the (growing...) to do list.
Please tell me what option you'd like to choose (splitter cable / additional IO ports) and then I will see how I can help you to get your system running soon.
pepelillo
Not really an issue but a Question.
This project seems to fit very well to my needs. I'm working in a forced vent system for a heat radiator. I need that the fans were stopped below some temperature, and most oem electronic pwm board do not stop the fans. But I need a lot of fans (probably 4 or 5 per radiator) so the question is: can I upgrade the system easily to more fans? (I'm not a developer) or is easier to have a 4 pin splliter (only one fan report RPM but all the PWM signal is sent to all of the fans connected)?
And less important for me, is the temperature and fans speed able to be reported to Home assistand via Mqtt or Json integration?
Thanks a lot