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Comment by nine_k | Hacker News Reader

AFAICT your home-grade wireless router / AP will start having trouble when you have dozens of Wi-Fi devices actively working in your home. ZigBee is somehow more resilient. It's also much lower energy, more comparable to Bluetooth, but much longer range: the sweet spot for smaller battery-powered devices.

OTOH I remember that ZigBee is somehow more buttoned-up than BT and even wi-fi, so it's not commonly seen on likes of ESP32 and other small MCUs.

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I think zigbee is more "resilient" because it piggybacks off all the other zigbee devices via mesh instead of each device talking to the central router.

Zigbee is also far lower data rate than even first-gen WiFi, which makes it more resilient. Radio protocols are usually a compromise between 1) range 2) power efficiency 3) throughput 4) robustness. Zigbee prioritizes 2, achieves 1 through meshing, 4 through error correction and other stuff, and mostly writes off 3. Point being it's not just meshing doing the work here, it is overall designed differently from Wifi and tuned for the purpose in multiple ways.

Note that 802.11 (original) is specified with 50% error correction at MCS 1 aka 1 Mbit/second rate. That is, for 1000 bits transmitted, 500 were data, and 500 were error correction. (Plus all the error detection codes like CRC32 on top of that).

This is a good example of tradeoffs: slower and less throughput, but way more robustness.

Higher MCS levels of 802.11 cut down on error correction to 25% or 10%, achieving more throughput but less robustness.

I dunno how Zigbee does it, but I assume it has more error correction at slower (ie: more reliable) speeds than even WiFi MCS 1.

You don't need to connect dozens of devices. Esp32 can communicate as a server or a client so you can directly connect them without getting the router involved.

Say, your house has 15 light switches on esp32 running Tasmota.

Do they all talk to each other in a mesh network, or do they all connect to your router in WIFI infrastructure mode?

There's a protocol called ESP MESH, with which multiple ESP32 (and ESP8266) can talk to each other.

> ESP-WIFI-MESH is a wireless communication network with nodes organized in a mesh topology using the simultaneous AP-STA feature on Espressif SoCs. It provides a self-forming and self-healing network, with ease of deployment. The network topology of ESP-WIFI-MESH can scale up to 1000 nodes in large areas.

https://www.espressif.com/en/products/sdks/esp-wifi-mesh/ove...

https://randomnerdtutorials.com/esp-mesh-esp32-esp8266-painl...

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I didn't know that home WiFi routers have difficulty with more than a dozen connections, but I imagine ESP MESH could be a way around it, where a few devices connect to your router and act as access points for the rest of them.

In addition to ESP-Mesh protocol as mentioned in the sibling's comment, alternatively ESP-Now protocol also enabled lightweight support for direct networking without AP:

https://www.espressif.com/en/products/software/esp-now/overv...

https://github.com/espressif/esp-now

There are some mesh protocols (ESP-Link i believe) but tasmota doesnt support them. It doesn't even support SoftAP for anything but initial configuration. However there are some wifi repeater projects for the ESP series that might be of use.

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