Hi Thanks for the suggestions.
I'm not totally sure on the existing circuit as it includes various wires going all over the place. I believe though that the switch I want to replace could be directly connected to the door magnetic lock, so I'm guessing with my very little knowledge that it could kick back a spike of voltage when switching on/off which I would need to protect against.
I'm thinking a relay would probably be a good option for safety (for my micro controller) with transistor and diode as per the above link to protect then against the relays spike. Should that then make the circuit safe?
Is this the kind of relay that I need: http://uk.farnell.com/omron-electronic-components/g5la-1-5dc/relay-pcb-spdt-5vdc/dp/1455502
I would like to simulate this so I can see it "working" and make a diagram. I have been using http://www.falstad.com/circuit/
for simulations. I'm having trouble though understanding what all of the parameters are that I need to enter to simulate it. Its asking me for:
On resistance (ohms):
Off resistance (ohms):
On Current (A): 72mA?
Number of Poles: 1
Coil Resistance (ohms): 69.4?
Could someone please tell me what the missing values are and if I put the correct values down for ones I believe are correct (data sheet: http://www.farnell.com/datasheets/96357.pdf
Thanks. I have so much to learn!