Change default status on reley USB-CH340

Hello,

I am new in this topics and sorry for my low exprencie and for my wrong comments.

I have a USB-Relay, with the chip CH340 USB, DollaTek LCUS. For more details its this realy:

I have connected the USB to compuerte and with the program sscom32E I can change the status about this relay:
A0 01 01 A2 to open, and
A0 01 00 A1 to close.

I have see the defualt status is "close". My question is, its possible change the default status to open?. I want that the USB is connected, the reley its open and not closed.

Thank you in advance.

There are three terminals, marked on the bottom: "NC, COM, NO". If you connect your circuit across the NO (normally open) and COM (common) terminals, then it will be normally open. Connect across NC and COM for the opposite.

Hello,

Yes, but its not works for my case, becasue I need when the USB is connected to compuer, there is a status change.

The problem now, the USB-releay dont change the status when is connected to PC, then it have the same status when is connected and when is not connected.

For this reason my question if its possible change the default status when is connected.

Hi,
What status of the relay do you want when the module is unplugged.

What are you trying to do?
Will the software switch the relay ON and OFF.
OR
Do you want the relay to be ALWAYS in one state when unplugged.
And ALWAYS in the other state when plugged in?

Tom.... :slight_smile:

Hello, I answer your question, but today in this morning I have get the solution:

Hi,
What status of the relay do you want when the module is unplugged. Close or NC.

What are you trying to do?. My objetive is put a electronic system (LED ilumination) actuated with the TV port. For this reason a I need a relay USB to connected to TV. When the TV is enable the relay change the status and wehn you turn off the TV, the relay change the status.
Will the software switch the relay ON and OFF. Yes, I get change the status with this program sscom32E and works correctly
OR
Do you want the relay to be ALWAYS in one state when unplugged. yes
And ALWAYS in the other state when plugged in? Yes.

The solution implemented is put a bridge to connecte directly +5v from the USB with the relay. Then, the result is when connecte the USB-realy to TV and the TV is turn on, the releay change the status, and the opposite when turn of the TV.

So your solution was a relay /powered/ by USB and not /controlled/ via USB-messages.

So the module you had was too advanced and could be replaced with a small 5V relay and a diode for inductive kickback protection.

// Per.