I have a device that switches from 0v to 9v DC when energised..
Anyone have any tips on which terminals to connect to to allow the arduino to switch.
Im currently using the 5v and input pins for 0v switching but this doesnt seem to work with this new device for obvious reasons!
any help appreciated!! ;D
Im currently using the 5v and input pins for 0v switching
You can't switch using an input pin it needs to be an output pin.
If the device is suitable for bottom switching then the simplest is to put it in the collector load of a transistor (common emitter configuration) like in this link:-
http://www.thebox.myzen.co.uk/Workshop/Motors_1.html
However if the device is feeding signals into the arduino or can't have it's ground switched that way then you need a PNP transistor. This needs feeding with 9V switching signal so you have to have a NPN transistor to switch that.
Thankyou for your help much appreciated.... 