Thanks for both replies. I will look at beacons and ANPR when I can get some time

I am finalising my project to open home security gates using mobile phone. However thinking ahead I have researched using ANPR (Automatic Number Plate recognition) This would be useful for friends and relatives arriving. However when I look at projects that have used a PI it would seem to me they wo...

Many thanks for that.
I will hang on to them. I have ordered some new ones. Fortunately they are fairly cheap and I bought them some time ago.

Hi thanks for response. Please see attched picture. I bought it off eBay and oddly enough the only one they have now have 3 inputs..

Hi, I have bought a relay board 5V DC One 1 Channel Relay Module for Arduino Raspberry Pi Pic AVR UK

However there are only 2 input terminals GND and UCC. All the articles I see require three wires.
How can I wire this up to operate please