Boost Circuit for Wi-Fi Module Digital Output

Maybe this will help...

https://hackaday.com/2016/12/05/taking-it-to-another-level-making-3-3v-and-5v-logic-communicate-with-level-shifters/

thanks Mr. Rixter for guidance i will try and let you know its working or not...

I am doing something similar but for pixel light control but the principle should work fine for a relay. The transistor method given in the previous posters link is the way I am going. Keep in mind that you will need both 5v and 3.3v power for this to work. That can be as simple as having a 5v supply and a 3.3v regulator. The schematic I used as a reference for my circuit is this one which comes from this page

You can buy logic level converters for cheap like this one as this is a common issue for many devices.

You could step up from 3.3v to 5v but I would't recommend it unless you don't have 5v available.

The design I am building needs to operate from between 4v to 12v so I have a step up and and step down converter as well as 3.3v regulator to make this work but you don't need that.

Let's not forget that the coil of a relay is an inductor. Thus when transitioning from ON to OFF a current path for the flyback energy should be in place in the form of a snubber. This snubber can be as simple as a reverse diode.

You need to connect the ESP output to the gate of an N-channel logic level FET (one that can be fully turned on by the 3.3V output of the ESP). The FET connects the Drain pin to the grounded Source pin (turns on) when the Gate pin is driven high by the ESP output. A 5V relay connected between a suitable 5V supply and the Drain pin of the FET will be turned on when the the FET turns on. You should put a diode across the relay with the band (Cathode) pointed towards the 5V supply. Your 5V supply must be able to provide enough current to turn on the relay (700mA?). Don't try to make a 3.3V to 5V converter, since it will require more than an amp from your 3.3V supply. Instead (as mentioned by another poster), get a good 5V supply and then run the 3.3V regulator from the 5V supply. Pick a FET rated at more than 1 amp, like a BSS816NWH6327XTSA1.

It may even be that the relay is totally unnecessary and that the FET itself can supply sufficient current to drive whatever is to be switched

Very true, with the FET it is basically an SSR at that point. If a mechanical relay is needed an Sonoff module for about $5 has the esp8266, the relay and power supply built in and wired might be the easier way to go. It is readily hack able to load your own code onto.

Yes, the question we need to ask is "what is the problem we are trying to solve?"

Perfectly solving subsets of the big picture almost always proved sub-optimal solutions. Determining what the relay is going to control may point to a much simpler solution.

??? https://en.wikipedia.org/wiki/Comparator#Level_shifter

many of the ↑1-s↑ have long transition/propagation delay !!!

. . .

(had nothing to do) i played around with the spice a bit - the following is just to illustrate the principal setup of such (this example uses different supplies for hi/low power nets to avoid accidental switching from rails' noise , . . . there are likely power buffers in a single chip , ... or then the entire stage from (isolated) 3.3 Inp -to- 5V Outp might be) . . . in pictures

A transistor and a sprinkling of other components would do this - probably about £2GBP-worth in total...