Door/Temp/PIR: MySensors or mix with cheap 433Mhz sensors - Opinions?

[chbla]

Hi there, I need your opinion:

Say you want to equip a room with 2 reed switches (2 windows), 1 Temp/Humidity sensors and a PIR.

For temperature I'm using DIY mysensors nodes (433mhz), and I could do the same for the windows and PIR.
However, I also have a RFXTRX433e for my blinds, and the price for 433mhz sensors is so extremely cheap these days
I wondered if I shouldn't just combine/mix those in addition to my mysensors nodes.

Reasons for chinese sensors:

• cheap (Door/Window sensor: 4.5$, PIR: 4.9$)
• no hassle, less effort to build
• nice case
• easy integration
• good enough for the task

Reasons against:

• I could combine 2 chinese window contacts into one mysensors node with longer wires if the windows are
  close to each other
• I could eventually re-use the temperature node (although the position at the window is not optimal)
• PIRs not very configurable (delay between triggers, etc).
• usually no batter state transmission (I would simply work around this with a trigger that if I do not receive
  an update within timeframe X, I get notified)
• security

I'm interested in opionions, I assume some people had this decision as well - what are the pros and cons you
determined?

Thanks,
Christoph

[gohan]

How about security?

[chbla]

@gohan Can you elaborate? You mean as a reason against the chinese ones? And due to what?

[gohan]

RF433 is pretty much a simple protocol without any security feature. Ok, every single frequency protocol is vulnerable to jamming, but RF433 is just open to everyone

[chbla]

That's a good and valid point speaking for mysensors - right now I only use them for my weather sensors so I did not look into security with the RFM69s yet.

[gohan]

The ultimate goal would be to have signing and encryption so that nobody can interact with your devices

[chbla]

@gohan is that possible with mysensors and the RFM69s? (I have it open, but did not yet read the security docs)

[gohan]

Sure it can be done, the only problem is the amount of flash of the pro mini that is limiting the amount sensors you can have when you have all securities enabled