How to get a potential free contact from an arduino?

Hardware Home Automation
5

Yes, i´m a native german speaker.

Please can you give me a link to aliexpress or something similar to the needed part for my arduino?

The arduino is my doorcontroller and if someone has the right rfid card, my arduino gives a signal on D7 - this signal i want to bring onto my potential free knx binary input.

So what would be the simplest working thing? A ready to use 5V relay board? This i can use without any soldering? Or do i need resistors/capacitor or something similar for this too?

Maybe this:

relais
https://de.aliexpress.com/item/1pcs-KY-019-5V-One-1-Channel-Relay-Module-Board-Shield-For-PIC-AVR-DSP-ARM/32802892040.html

relais with optocoupler
https://de.aliexpress.com/item/Smart-Electronics-FT232RL-FT232-FTDI-USB-3-3-V-5-5-V-to-TTL-Serial-Adapter/32801726574.html

or

https://de.aliexpress.com/item/5-pcs-1-Channel-RM-Optocoupler-Relay-Module-Shield-for-Arduino-ARM-PIC-AVR-DSP-Electronic/1671974644.html

reed relais:
https://de.aliexpress.com/item/10pcs-lot-SIP-1A05-SIP-1A05-DIP4-reed-relay-5V-Voltage-Hot-Sales/32822265139.html

or a simple optocoupler without relais:
https://de.aliexpress.com/item/1-Channel-Optocoupler-Isolation-Module-Input-12V-No-Din-Rail-Holder-PLC-Processors-80KHz-PC817-EL817/32719957788.html

Which one is the right for me?