How turn on my device without relay.

I have a usb device that I am connecting to arduino using rx and tx. Everything works well so far. I can see the datas.

My device has a manual trigger. When pressed, the device works.
The trigger closes a connection. I measured and I see 3.2 volts in the wires.
I want that arduino turn on the device. I tried to use a relay but it is very noisy.
Could I use the GPIO pins to close the circuit? How do it?

Should I bind the positive wire on GPIO ? Negative? Should I use a resistor?

Thank you for help and your time

What is the voltage w.r.t. USB ground for both trigger wires, both untriggered and triggered?

Hi,
Welcome to the forum.

Please read the post at the start of any forum , entitled "How to use this Forum".
OR
http://forum.arduino.cc/index.php/topic,148850.0.html.
Then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Thanks.. Tom.. :slight_smile:

Get the Arduino cookbook by Michael Margolis and read it. You will find on line many videos etc showing the Arduino and how to do use it some of it may be what you want. This additional information will go a long way in getting your problem solved. There are also many videos showing how to read a data sheet. Once you get past this you then need to select your sensors and actuators. At that point you start on the hardware design and write your software.

Post a link to the device product page or user manual.