“Blynk, is it the savour of microprocessors everywhere? Well at first look this seems to show promise, so let’s take it for a spin and see.
While looking for a unique way to control a two-stage green-house, I came across “Blynk”. ( https://docs.blynk.cc ) I just followed the very simple and easy instructions at Github/Blynk. I got a working server on a Raspberry Pi in no time! Follow this link below for complete instructions on setting up your own server, note that if you are going to use a local server, you will have no access to your network and the server if you are not connected to the network the server is on. https://github.com/blynkkk/blynk-server#quick-local-server-setup-on-raspberry-pi. Once you have your server up and going, the app will connect to your server (remember to setup the custom server values), now you can then create and run your app on your phone.
I then took an esp32 and added an ULN2803 buffer driver, wired up 4 12volt fans (2 fans for exhaust, 2 for recirculate) and a couple of lamp driver relays via 120vac. Attached to the i2c bus of the esp32 are a few of sensors, a bme280, ccs811 and a HDC1080. Each of the sensors outputs are routed to virtual pins so they can be tracked by the server. The pins controlling the fans are assigned digital values so they may be controlled by the Blynk app.”