Hello, I have a 24V fan that i want to toggle with a esp32. I have a power supply of 24V. I guess i would need a step down converter to power the esp32 and a replay to toggle the fan. Can somebody share any schematic or point to a relevant project?
Easiest way would be Shelly Plus 1, it works at 24VDC out of the box. I warmly recommend.
Otherwise you need stepdown or separate power supply (usb charger for example) for Esp32 and 3.3V relay module.
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If this fan is part of an hvac unit it’s likely 24VAC not DC. It doesn’t seem like the shelly can be powered by a 24VAC input.
I wrote 24VDC.
Neither stepdown converter can be powered directly from AC.
Shelly Uni can be powered from 24VAC, but it can switch only very moderate loads, ~300mA.
- ESP-01 + ESP-01 relay (10A) ~USD$2.50
- Step down power supply ~USD$2.00
You’ll want a case. Free, if you use an yogurt container of something like that.
If you really want to use your ESP32, you could wire into the ESP-01 relay board.
I haven’t used and ESP32, but an ESP8266 requires ENABLE to be wired to 3V3 and a pull-down resistor (10k?) from GPIO15 to GND to start up.
Good project!
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You should! 
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there is no AC involve here. Its PC cooling fan, trying for 3D printer filter.
Thats very interesting. Shelly plus 1 serves all i need but in a single package. thanks.
24VDC right?
yes.
btw does 24VAC exist?
Very common in “traditional” devices. Rarely used in modern ones.
If you check the link to the power supply, it accepts DC input.
Many step up/down power supplies are AC or DC input because they are switching power supplies. The input goes through a full wave rectifier to effectively make the DC voltage required for the switcher.
Having all in one neat package, though, is very appealing.
-OSD
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I have the zigbee version of this relay. Works very well in HA. Can be directly powered from 24 V as well. https://ewelinkstore.com/product/smartwise-5v-32v-1-channel-sonoff-compatible-wifi-remotely-controllable-smart-relay-switch-with-contact-and-momentary-switch-mode/ . It’s also available in multi-gang types and you can get a case with it as an option
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It’s correct.
But I suggest you to not use Shelly as a connection for LED power and fan negative. Three wires don’t even fit in Shelly connector. Make PSU as connection point (or separate screw connector).
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yes, i used some connector for to connect multiple wires. i couldnt fit more than 2 wires in one slot of shelly. thanks 
But the point is, tiny PCB screw connectors are weak. Either you leave them loose or you break them. And it’s not easy repair when that happens…
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Use a wago to split the cables.
Much safer connections.
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