Wireless switch using ESP8266

Question

I am a software developer, sorry if my question may sound dumb.

I want to make my home smart by controlling lights through a centralized smart home web page. So rather than buying ready-made wireless unit I want to make it by myself (it will be a fun and satisfying).

A centralized Web page will contain buttons for lights in my hall/kitten/bedroom. So while search for this I come know about ESP8266 wifi module which works on STA mode. Also, I may need a relay which will take signal from wifi module and on/off the light but as I am a novice in this I have some questions:

1. Which ESP module need to be selected? there are two variants I see on net one is NodeMcu and another is ESP-01, which one I should go with?

2. If I want to control 2 lights from a light switch panel, then is it possible control it by using 1 wifi module and 2 channel relay module or I have to buy 2 wifi module (no. of lights in a panel = no. wifi module) one for each light?

3. Both relay and wifi module works on 5v, What should I use to pull 5v from the 250v power supplier? On net I've seen switching power supplys but these are all bulky and contain transformers. I was hoping that there was a smaller solution.

Answer 1

p.s.: From the level of your questions I assume you are starting with electronics, and I should say this is not recommended as a first project because mains voltages can kill or severely harm you either due to direct shock or fire, etc. Please consider doing a similar project controlling lower voltages first (12VDC for example).

1.NodeMCU will give you much more GPIO and is arguably easier to develop on due to the onboard USB to serial converter. It is also easier to plug into breadboards.

2.You can control 2 relays with 2 outputs from the same microcontroller (with the appropriate driving circuitry, unless you are using modules like this or similar, which already contain the driving circuitry). No need for one ESP for each relay.

3.You can probably use a 5V phone power supply ("charger"), provided it can supply enough current for all the relays you are using.

^{simulate this circuit – Schematic created using CircuitLab}