Hi All, I have an esp8266 that I want to attach to my hot tub and relay the water temp I 've ...

[G+_Robert Kaczanowski]

Hi All,

I have an esp8266 that I want to attach to my hot tub and relay the water temp. I've attached a temp sensor that I'll attach to the outside water circulation pipe inside the cabinet. Only issue is getting 5 Volt DC from the 220 Volt AC supply.... The 220 Volt is actually 120 Volt on 2 cables.... (if you know how the 220/230/240 V is supplied to residential houses)... So, how do I get from my 220 V AC down to 5 V DC for my esp8266?

Thanks, -Robert

[G+_Michael Hagberg]

An electrician can wire in a 120 volt GFCI outlet. From there you can plug in any standard wall power pack.

[G+_Rud Dog]

Michael Hagberg If you are running 220VAC the circuit is probably protected by a 220 Volt circuit breaker branching off that directly is not a good thing. Also to get 120 VAC you will need a neutral wire (white) to get the that (120VA)voltage. Will leave the 5VDC to others for clarification.

[G+_Michael Hagberg]

Another thought I had was to use a 220 volt power supply down to 12 or 5 volts. Again please don't play with the 220 volt wiring unless you are very sure.

[G+_John Sullivan]

If you only have the two 220v wires from your circuit breaker box (plus ground), then you would have to run a third wire from the breaker box Neutral to the hot tub cabinet in order for an electrician to install a 120v outlet.

 

An alternative would be to use a 220v to 5v power supply. In the US, devices like smartphones use a USB charger that converts 120v to 5 v. In Europe and other countries, they use 220 v, so you can easily purchase a 220v to 5v charger and use that. Then your electrician only needs to install a 220v GFCI outlet, and doesn't need the Neutral wire. Be sure to discuss your whole project with him, in case there's a local code that would prohibit this, and he has a better idea.

[G+_Ben Reese]

Yes. If wired correctly, you should have 4 wires coming in. Typically red, black, white, and bare (or green). White SHOULD be your neutral. But really, 3 wires is all that's needed and you may not have a neutral. In that case you can use the ground wire as neutral and get 120 off either leg of the circuit, but it's not recommended.

 

One other option would be an European 220v power supply. It may expect 50 Hz instead of the US 60 Hz, but I've seen plenty of International power supplies that work both places, so maybe the frequency wouldn't be an issue.

[G+_David Peach]

If it were me, I would just plug in a USB phone charger and see what happens. Check the charger first but I would be surprised if it were not rated for 110/220 V AC. The only thing that may be an issue is the 50/60 Hz issue that Ben Reese? brought up.

 

I've recently used my US USB phone charger in 5 different countries that use 220 electricity. But they are all 50 Hz systems as far as I know. You will be getting 60 Hz here in the USA.

 

Most small electronics that have an AC/DC converter work with both 110 and 220 these days. Always check your device before haphazardly plugging it in. The only thing I don't know is what the difference in Hz output is.

[G+_John Sullivan]

Although you may have the four wires (two hot, one neutral and one ground) appear at your breaker box, we don't know what your hot tub installer ran out to the tub. If they weren't also installing something that needed 120 v (lights or whatever), they may not have run the Neutral wire.

 

No disrespect to Ben, but using the Ground wire as a return to make 220 into 120 is a very bad idea, especially around water (a hot tub) and is probably against your local electrical code.

 

Probably the wires to the hot tub are protected by GFCI, so hopefully any current appearing on the ground wire would trip that, and the whole thing would never work anyway.

 

As others have said, using a 120 /220 to 5 V converter is an option after you have an electrician install a 220 outlet. You may need an adapter in order to plug it in, depending on what style of 220 v outlet gets installed.

 

I don't think you need to be concerned about 50 Hz vs 60 Hz, as long as the device is putting out 5 v DC not AC

 

There might be a slight voltage increase above 5 v due to the device being fed at 60 Hz, but your ESP should not be bothered by it.

[G+_Sean Miller]

speaking as a guy recently back from living in Germany, almost all usb chargers can receive from 100-240v at 50/60 hz automatically. read the label where it says input. The only catch is finding an adapter plug so the wall wart can physically fit into the 220v plug.

[G+_Ben Reese]

cosmic Ray hey, I said it wasn't recommended ?

[G+_John Sullivan]

Ben Reese Hi Ben ... yes, you did ... I just wanted to change "not recommended" to "definitely don't". Thanks.

[G+_Michael Hagberg]

Here's a thought. How about batteries? If you were to power the esp8266, temperature probe and a solid state relay from a battery pack I would think the power drain would be low enough that you could run for an entire season on a single set of AA batteries... Just a thought.