I've been a programmer for the last 6 years but have only just taken up hardware.
I have written all the code I need for my project but have hit a problem, I need to press buttons on devices such as a tv remote or a calculator.. I know this may sound generic but this is partly the idea. Anyways I know that the buttons work by creating a circuit when a button is pressed down and the conductive pad touches the circuit but I need to do this from my arduino. I have tried sending digital out and connecting one side to ground but when trying to connect several buttons this method broke. So my idea is to use a transistor connected to each wire out from the arduino as a conductor when a current is passed through the middle leg.. I was just wandering, how would I go about connecting the transistors? Or does anyone have a better idea for how to do this?
You need to wire a FET across the button you want to press not a transistor as this acts as a controlled resistor not a current flow device.
However, there are many ways to implement a button in the target device so your approach must change to match it. Sometimes a simple commoning of grounds and an arduino output straight to the pin will work, or if the voltages are not compatible then a FET is needed.
In other situations the target device has a scanning matrix key input, there you have to short two signals together and pick up a common ground.
In short there is no generic answer to this question.