Short circuit with Arduino

Forum 2005-2010 (read only) Hardware Interfacing
1

Welcome everyone,

I'm new with Arduino, so I want to ask you for sth:

How should I create a short-circuit thing with arduino?

Now I'm using Digital Pin 5 (1rst wire) and GND (2nd wire).

I want do like this:
PRESS BUTTON (for example SPACEBAR),
and
PIN 5 connect to GND.

I want to release special thing, I have manual button to do this, but I want to do from the computer.

Do you have any suggestions?

Maybe connect 2 pins each other?

Grettings

2

It depends on how much current the "short" is going to sink. If you expect it to take less than 40mA you can just connect it to your digital pin. If you expect it to be more then you have to arrange a transistor, FET or relay that will take the current.

As to the controlling it with the computer, you need some sort of language or terminal program on the computer that detects the key press and sends an appropriate message over the serial port. It's a virtual serial port caused by the USB interface. Then the arduino waits until it sees that message and outputs a logic low when it does.

Look on the playground for extra help>
http://www.arduino.cc/playground/

3

Thanks Grumpy_Mike for your reply.

About controlling: there is a simple Delphi Code, that I'm using.

Could you explain me , what you mean "you can just connect it to your digital pin." (Pin + Ground)?
In that case I have short-circuit always (not when the Pin is HIGH).

What kind of transistors should I use?

About my trigger: this is a simply tool. I can manual trigger - I have two cables, when I connect them, I have release.

Cheers
Tomek

4

"you can just connect it to your digital pin."

Connect one of your wires to the digital pin and the other end of your wire to ground.

In that case I have short-circuit always

No when you put the pin high with a digitalWrite(5,HIGH); there is no short. When you put it low with a digitalWrite(5,LOW); it is connected to ground and hence your other wire. It is shorted out.

this is a simply tool. I can manual trigger - I have two cables, when I connect them,

Sorry that is not enough information. How much current flows through the two wires when they are connected together. If you don't know you will have to measure it with a current meter.

To be safe you had better use a relay, see this page:-
http://www.thebox.myzen.co.uk/Workshop/Motors_1.html
the start tells you how to connect up a relay.