LED and LCD widgets

No because when it’s asleep the ESP doesn’t have an internet connection.

You can get it to respond to signals you have sent to the Blynk server whilst it was asleep with the sync command but not until it wakes up.

okay, so what is the advantage of the sleep function?

For projects that run on batteries.

@Costas

Do you know if it is a problem to trigger with the ESP8266 a 5V relay on which output is direct connected a 230V Light?
I want to use a relayboard with 5V Relay, Output 230V COM/NO/NC

Ideally for an ESP8266 you need a relay that will trigger at 3.3V and is fully isolated from the 230V supply.
Espressif have publicly announced that the data pins can tolerate 5V even though they are 3.3V devices.
It’s your risk if you accept what they say and kill your entire street.

@Costas

So you think nodemcu and arduino 5v relay for trigger 230v liggt is a problem?

Where is the problem when I trigger a 5V relay with 3.3V?

If you are linking the ESP with a 5V Arduino then the normal 5V activated relays should be fine. Just take care how you hook up the connections between the ESP and the Arduino. Probably OK but ESP’s are 3.3V devices and Arduino’s (except the Mini) are 5V devices.

I have never used a nodemcu and prefer the WeMos. Either nodemcu is more popular than a WeMos, nodemcu’s have more problems than the WeMos or WeMos users are brighter :slight_smile: but we seem to see more problems on this site with the nodemcu than we do the WeMos.

I received an email only yesterday from a company that does a lot of work with ESP’s and without any prompting they said they prefer WeMos to nodemcu.

At the end of the day a WeMos is just a clone of the nodemcu so there is very little to choose between them.

@Costas

And what do you think about this relay, can i trigger with 3.3V?

All I can say is probably. Like most Ebay listings there are no details of what they are actually selling.

They have included ESP8266, NodeMCU, Arduino ARM in the title listing as a catch all for anyone searching for a relay for their MCU. All it says is 5V. An ESP working at 3.3V will probably trigger the relay but without seeing the full specification it’s difficult to say.

Looks like they are out of stock but I would just send an Ebay question asking them to guarantee that it will work with 3.3V MCU’s. If they are not prepared to guarantee, keep shopping.

These look ok for 68 cents including slow delivery but the same question applies.

1 channel relay

@psoro can probably recommend a Far Eastern supplier of relays that 100% certain works at 3.3V. He might even have given me a supplier previously.

@Costas

Yes it seems that it should work.

What abot logic level converter from 3.3V to 5V?

Take a look at one of @psoro’s projects at Automatic scheduler. ESP-01 with 4 Time Input Widgets

There is a link to bare 3V relays and @psoro uses a transistor to switch the 5V relay from a 3.3V ESP01.

I will check thanks.

But what do you think about logic level converter from 3.3V to 5V?

I would buy the correct relay and forget logic converters.

@Costas

i cannot find a link in the project above.

Do you think I’m crazy @Tom?

Look through the whole thread, the link is there.

It’s a thread you should read several times if you are planning to work with relays.

@Costas

No believe me, i do not think that. I am so happy and thankful that you help me so much!!!

@Tom
Look at this on eBay http://www.ebay.com/itm/351748538371

@Costas, you have the patience of a… Saint? ^^

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@Costas

now i have it:

SRD-03VDC-SL-C 3V DC

And you think these relay i can trigger direct with GPIO without any additional condensator or something else?

@Costas,
Not sure about this conversation regarding 3.3V relays…All relays I have are 5V… But I’m a little bit sleepy at this time…:sleeping:…I could be wrong

@Tom,
There are boards with optocoupler, I’ve got one of them and it works fine at 3.3V

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