Also, if that is the best way, would the correct way to wire it up be an Digitial pin from Arduino into one of the IN connections, GND from Arduino into the 9th hole on the front (marked GND) and the live from the lamp into/out of the corresponding backside?
If datasheet says those SSR can cope with your voltage and reqv. corrent - you can use it.
Control on/off our 8 lanps indepentdenly, or choose an other variant SSR (there are several out there)
Your connrection to Arduino is OK - find the schematic!
OK, then the first choice sounds the most appropriate. Except that having only the picture, we cannot determine the actual specifications.
The main concern here is that your questions and less-than-sure allusion to the "UK mains outlet power" suggest that you do not have the skills to work safely with mains-connected equipment and would be better advised to obtain a ready-made and safely constructed solution. In America, this is called the "PowerSwitch Tail" and something similar is probably available in the UK.
This is also far simpler to connect to the Arduino as it requires only two connections - ground and an Arduino port. Relays (electromechanical) are in general troublesome to use with the micro-controller, requiring more current to operate and thus buffer transistors (as in your first example) and one module cited so far was actually a 24 volt type - even more difficult to implement.
Well my brother and Dad are both professional electricians so I will get their help whilst building, I just want to make sure I'll be buying the correct equipment. I will look for a PowerSwitch alternative in the UK, see if I can find anything.
Well my brother and Dad are both professional electricians so I will get their help whilst building, I just want to make sure I’ll be buying the correct equipment.
Well then, get them to box it up for you with the mains cord and outlets so that you just have the control wires coming out of it - like the said “powerswitch”. I have built such things in the past (still unused - somewhere!).
I think the first unit you cited would probably suit - just make sure of the voltage and current ratings - those are rather small SSRs (but a good brand - OMRON if it is to be believed). It requires a extra power connection using the voltage you use to feed “Vin” on the Arduino, not the Vcc from the Arduino.
Because the board implements buffer transistors to actually control the SSRs, it requires its own power connection on the terminals marked "VCC" and "GND". Since we only have the link to that photograph, we do not know what voltage is expected to make it work or what maximum current it might draw if all SSRs are simultaneously switched on, so it is difficult to guess whether it might be possible to power it from the Arduino or not.
If you are always going to use the Arduino connected to your computer, then the USB port can provide up to about 500 mA which is actually more than the regulator on the Arduino board can reliably handle when powered through "Vin", so you may be able to get away with it.
The hint is: Provide a link for the actual description and specifications for that board.
start at the beginning ?
You want to switch a lamp on/off (or 8 lamps with the choise you showed at the top)
I'm sure those SSR can cope with a 100W lamp each as datasheet says: "Output with resistive fuse 240V 2A"
.. and each controlling input can be controlled directly from arduinos i/o-pins (20mA pr. pin)
To me this seems like the solution with the minimum fuzz. Only connection wire is needed as 'extras'
The relay variant will need special handling for powersupply to the coils
each SSR can handle 0.1 - 2A (100-260V) -> ca 20W .. 300W This is mains side
"Arduino side" says 160mW (all 8 channels on). 20mA / channel
Take a good look at "arduinos specs". Up to 40mA/port... BUT combined max current. (you'll find it)
These are specified as "zero-crossing" switching which is good. They have a minimum voltage/ current specification for the TRIAC components, in this case 100 mA or 75 volts. At 110 Volts this corresponds to about a 10W lamp fitting whilst the 2 Amp upper limit would correspond to about 200W.
The module operates at 5V and the trigger current for each "relay" being 20 mA to total 160 mA (milliamps), this could be supplied from "Vcc" when operated from USB as long as no other associated devices draw too much, but it would not be advisable to use a supply on "Vin" to the NCP1117 on-board regulator.
The current draw from the Arduino chip ports is not mentioned, but is very low to control the buffer transistors - that is not a problem at all.