Which RF module is best for my project?

Using Arduino Project Guidance
1

Hello,

I'm working on a project of wireless synchronized digital clock system in master-slave mode.
A Master clock will send time data in a string format ex. “18:32:50” at regular interval (say 6 hrs)
through a wireless module and all slave clock will receive string data and update the time in its RTC DS3231.

I have made such clocks using Arduino neno, wifi module esp01 and RTC ds3231 and working successfully on my existing wifi network,
But Range of wifi network is limited. I want to make it work for larger area such as school campus rooms or 3/4 story buildings situated 100 -200m apart .

So the constraints for selecting a wireless module

•** Range- Indoor area of 3/4 story buildings situated 100-200m apart.**
• Transmission delay/ latency- less than 500ms.
• Not necessary to have two way communication.
• Power consumption - As clocks are DC adapter/ mains operated power consumption is no issue.
**• Serial interface (preferably) - As I mentioned I have already made such clocks using ESP01, and getting data through its serial pins. **I can replace these ESP-01 module without much Hardware or software change.

I have gone through many articles about LORA/HC-12/ 433 MHz transmitter and receiver module but still confused about its range and latency. Please suggest a suitable RF Module.

2

Sounds like a LoRa project to me.

3

make it an NTP server and point all the clocks on the network to it

4

atul2_m:
I want to make it work for larger area such as school campus rooms or 3/4 story buildings situated 100 -200m apart .

LoRa is the obvious choice, as it could go between 10 and 30 times further than a HC12 for instance.

For some information of LoRa speed see here;

But there are no guarantees, you need to get a TX and RX pair working (of your chosen modules) and try it in the actual environment.

5

Thanks for valuable information