Feasibility of Large-Scale Alarm System Using Sonoff Basic R4 & iHost (Offline Capable)

Ideas & Suggestion Free discussion
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Hi everyone,

I’m working on a concept for a large-scale alarm system using Sonoff devices, and I’d like to get your feedback on feasibility—especially from those with experience using Sonoff iHost and Basic R4 devices for offline automation.

:wrench: System Overview:

  • 20x Sonoff Basic R4 will be used as manual call points (MCPs) with physical push buttons wired to their switch terminals.
  • 30x Sonoff Basic R4 will be connected to siren alarms (220V) to trigger audio alerts.
  • Sonoff iHost will be used to manage the automations locally (no internet dependency).
  • All devices will connect over WiFi via a single LAN network (no cloud required).

:repeat_button: Automation Goal:

If any of the 20 MCPs is triggered (physical button press), all 30 siren R4s should immediately turn ON.

Additional automation may be added later to auto-reset sirens after a set duration.

:white_check_mark: Key Requirements:

  1. The entire automation should run locally via iHost, functioning even during internet outages.
  2. Automations must have minimal latency between trigger and siren activation.
  3. Scalability—will iHost and the eWeLink CUBE be able to handle 50 Basic R4 devices reliably?
  4. Efficient way to define automation (e.g., group 30 sirens in a Scene or Device Group to avoid creating 20x30 individual actions).

:red_question_mark: Questions:

  • Has anyone implemented a similar setup or tested iHost with 40–50 Sonoff WiFi devices?
  • Can the iHost handle these many devices smoothly in terms of response time and reliability?
  • Is there a smarter or more efficient way to configure this automation logic (especially grouping the siren devices)?
  • Are there any known limitations on simultaneous automation triggers or group actions?

I’m aiming to use Sonoff solutions to build a smart yet robust emergency response system for a large premises, while maintaining offline capability for reliability. Would love to hear your thoughts, suggestions, or potential pitfalls I should be aware of before deployment.

Thanks in advance!

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If the devices are within range of WiFi routers, it will probably work, but be aware that if one day, for example, some of the devices start to randomly go “offline” and this entire intricate alarm network falls apart, you will have to solve the problem yourself because you built it on toys whose manufacturer does not provide any technical support beyond “delete and re-pair the device in the Ewelink app…”