The right radio-interface for security system

Hello! I'm sorry if it is not the place to ask. Soon I am going to move from appartment to my home and I want to make a simple security system.

It will be a set of reed switches and magnets or Hall's sensors mounted on the doors and few windows. The sensors will be connected to attinys or Arduinos which over some radio transmitter will send data to the receiver on raspberry pi to analyze further.

I saw that there are some options in the radio interfaces. But I cannot decide which one to choose. The problem is that I need a few, at least 2 transmitters that must work together without interference. Also I need some transmitters that are energy efficient and have a small amount of wires(to connect to attiny). The connection speed is not crucial at all as well as coverage range.

Help me please to choose the right radio-modules. Thank you!

Before you get to transmitters, is your system going to report a door/window it now opened, or is it going to report continuously that all is ok?

Paul

Hi, Paul! Continuous monitoring would be a good option, but I'm planning a simple system that make triggers when door or window is opening. UPD. I think I get the logic. I can use one receiver and a few transmitters and when one is triggered I get the message on the receiver. But how exactly I could know from where it triggers?

Use something like the RFM12 ISM modules, send a packet containing the relevant information (which node, what happened), and check for an acknowledgement. These modules are basically 3.3V SPI and small and pretty cheap. You can get versions for each of the 433, 868 and 915MHz ISM bands, note a particular RFM12 module is fixed to a single band, it cannot be retuned.

Thank you, MarkT! Yeah, they suit my purposes except the amount of wires. Unfortunately I could not connect this module to Attiny.

Maybe something like this which has MCU onboard and talks serial? https://www.digikey.com/catalog/en/partgroup/433mhz-wireless-serial-transceiver-module-1-kilometer/60255

Why not use Zigbee? There are smart door sensors in the market that use Zigbee.

like this one for example

|500x319

search 'mysensors' - a lot is already done here... :)

Noobian: Why not use Zigbee?

How could I use them without base, like Xiaomi Home? Is there some cheap bases as alternatives?

MarkT: MCU onboard

Yeah, thank you! I think, I would use them if do not find some cheap bases for ZigBee.