Hi, I am designing an IOT power project for an appliance and USB device at home. I have a question around using relays controlled by my low voltage micro controller to switch high voltage switches. There are numerous "how to" guides for creating IOT 120 plugs online, they all seem pretty straight forward. I am wondering if someone can help me consider an approach to control 2 devices with a micro controller, one 120VAC and one 5V (typical USB powered device). See example schematic below, I put in the micro controller I will be using and a relay I found for 3.3V controllers to switch 120VAC (I am not wedded to that relay, just for example purposes). I would love some advice on relay's to consider for both the 120VAC and 5V side. Also, I am not sure if using a relay for switching the 5V USB device is the way to go, open to any options.

Also, would it be possible to design this to take in the single 120VAC power and supply power to the micro controller and both devices, for a more elegant solution (removing the need to power each device separately)?

Thanks in advance.

Components in example:
ICStation 1CH
ESP8266 NodeMCU Micro Controller

 

MOD NOTE: PLEASE! One thread per topic. Since this is the first one you started, let's go with it. All of the others will be deleted.

 

Can be done with one relay if you want switch both on at same time
5 volt on the right com
120 on the left com
Oh and there is nothing wrong with using a relay lot less problems with one
And a plain old npn is easy to use with a 3.3 volt uC
easy to find one and seeing they don't need much to switch
The 2n2222 has no problems with most small relays
it and 3n3904 are used more then any you can think of just for driving relay coils
with low voltage uC

You'll need a 2n2222 and 1n4007 diode and resistor to limit current on the dive pin
A 2n2222 is easy to switch from a 3.3 volt uC
They sale a 3 volt one too.
https://www.te.com/commerce/DocumentDelivery/DDEController?
Action=showdoc&DocId=Data+Sheet%7FRZ%7F0918%7Fpdf%7FEnglish%7FENG_DS_RZ_0918.pdf%7F1415899-7

 

MOD NOTE: PLEASE! One thread per topic. Since this is the first one you started, let's go with it. All of the others will be deleted.

Fair enough @WBahn. I searched this forum for any articles about posting the same topic into multiple forums thinking it might nor be appropriate - but the only article I could find was this - which gave me the impression that it was acceptable (see replies). I would suggest posting an official article or perhaps a portion of the PLEASE READ sticky threads to address this policy, as I read those as well to find guidance. Thanks.

 

Can be done with one relay if you want switch both on at same time
5 volt on the right com
120 on the left com
Oh and there is nothing wrong with using a relay lot less problems with one
And a plain old npn is easy to use with a 3.3 volt uC
easy to find one and seeing they don't need much to switch
The 2n2222 has no problems with most small relays
it and 3n3904 are used more then any you can think of just for driving relay coils
with low voltage uC

You'll need a 2n2222 and 1n4007 diode and resistor to limit current on the dive pin
A 2n2222 is easy to switch from a 3.3 volt uC
They sale a 3 volt one too.
https://www.te.com/commerce/DocumentDelivery/DDEController?
Action=showdoc&DocId=Data+Sheet%7FRZ%7F0918%7Fpdf%7FEnglish%7FENG_DS_RZ_0918.pdf%7F1415899-7

Cool, thank you @be80be - appreciate the response. I will check out the 2n2222 and 1n4007 - however for my particular application, I will need to control the 120VAC and 5V independently - so I think I would need another relay to allow for that?

 

I would suggest posting an official article

Its thought to be pretty general knowledge in the forum worlds I think. No big deal really. It will get cleaned up and original poster informed.

 

Its thought to be pretty general knowledge in the forum worlds I think. No big deal really. It will get cleaned up and original poster informed.

No disrespect @narkeleptk, but that is a bit to my point, I guess I am not a native of the forum worlds and was honestly trying to determine the etiquette here and be respectful, so it likely would help others too who are aren't regulars.