@ivik80, yes, check arduino or better yet get a nodemcu v2 and look at the blynk library and free iphone ios app. nodemcu is a very very small arduino-clone with builtin wifi (it costs about 2-5 โฌ/$). there are other multipurpose arduinos (clones) with wifi.
blynk is a framework you can easily add to your sketch. blynk /arduino then connects to either a free cloud server hosted with them or (as i did, as a docker container in parallel to an openvpn server on a NAS) you can run it locally on a small server, so everything stays private. What is nice, the server feeds your arduino the current time now, also it can collect all kind of sensor data in your growroom. You can then build a dashboard app, all kinds of graphs easily in a matter of minutes and program your own light scheduler. it is amazingly awesome. ALso cool: once everything is installed you can update your sketches via wifi, feed videos or webcam shots of your growroom into the app, override the light status in your app, emergency heat shut down, push notifications, all kind of stuff. its nerdy AF, but also a very fun tech project if you're savvy. you can even let the units talk to each other, which i have not tried, build individual humidity/temp-nodes per tent or pot.
adding or simulating a potentiometer would be a step depending on your tech setup then.
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