Hi, I'm very new to all of this, so any advice will be greatly appreciated.
I have purchased a linear actuator, http://www.gimsonrobotics.co.uk/GLA750_12V-linear-actuator.html and want to control it using an Arduino Uno. I want to control its extension, how long it is on for, and then have a pause, and then retract it. Relatively simple...?
That actuator has no position feedback, do you need to know the exact extension? I hope not because that will be very difficult. But if you just want full extension you will be OK.
As for the relay board, it says 2-channel in one place and 4-channel in another and I don't know exactly what "2-way" means.
You need a DPDT (Double Pole, Double Throw) relay or two SPDT (Single Pole Double Throw) relays but there is not enough information to tell what that is I think.
Looking at the board each relay seems to have 3 connections, that implies that they are both SPDT. If so you can use the board, does is have C, NC and NO printed somewhere on the PCB?
It looks like a simple DC motor/drive assembly. If you want it to be reversible, an H-bridge motor drive circuit (with suitable voltage and current ratings) would be the best way to do it. An alternative but much cruder approach, giving you less control over the speed, would use relays to turn the supply on and off.