Tips

Command latency and device state sync

• Command latency means: how long it takes for a MQTT state change command to be issued and for the physical device to change state.
• Device state sync means: HASS light group of 9 issuing off. How in-sync the devices are when changing state, one after the other or in parallel?

Fine-tuning

There seems to be some fine-tuning that can be done using CYNC_MAX_TCP_CONN and CYNC_CMD_BROADCASTS env vars.

• CYNC_MAX_TCP_CONN is the maximum number of TCP devices connected to cync-lan at a time. This is set to 8 by default.
  • I've had a decent experience with 4-6 devices connected at a time and 2-3 commands broadcast.
• Having 2-6 WiFi devices connected to cync-lan is recommended.

Note

It may also be the way HASS issues commands in a light group. I also notice slow / not in-sync responses with ZigBee lights as well

Some devices are better at being TCP <-> BTLE 'bridges'

1. LED strip controllers are the best bridges in my testing
2. Bulbs, possibly down light / wafer / under cabinet lights as well
3. Switches are untested
4. Indoor/outdoor plugs are ok

Use CYNC_TCP_WHITELIST to limit access to the cync-lan server

• This is a comma separated list of IPs that are allowed to connect to the cync-lan server
  • By default, all IPs are allowed to connect
• This allows you to choose certain devices to connect to cync-lan (and also limit how many devices)
  • Set the IPs of always on devices and prefer the better 'bridges'
  • Example: CYNC_TCP_WHITELIST: '10.0.2.20, 10.0.2.24, 10.0.2.29, 10.0.2.30, 10.0.2.33'
  • This will allow only those IPs to connect to the cync-lan server, which also only allows a max of 5 devices
  • Now try fine-tuning CYNC_CMD_BROADCASTS to see if you can get better performance (also try increasing / decreasing connected devices)

Motion + Ambient light sensor data

Motion is available and works. Standalone motion sensors and the motion sensor built into some switches show up as Home Assistant motion binary sensors, updating from the mesh in real time.

This is worth stating plainly because it used to be false: the readings are not in the Cync cloud API, and the older advice here was to ask Cync support to expose them. That turned out to be unnecessary. cync-lan reads the motion state off the mesh directly, so nothing has to be exposed by the cloud at all.

Ambient light is a different story. The hardware has an ambient-light sensor and cync-lan can configure it - enable/disable, sensitivity, timing, via the experimental motion-sensor settings - but the ambient-light reading is not currently surfaced as an entity. Only motion is.

Motion sensors are battery devices, so they sleep. Anything that writes settings or schedules to one requires waking it first: hold its off button for five seconds until the LED turns green. Home Assistant refuses those writes while the device is asleep rather than sending into the void, and tells you why.