NY wrote
Rod Speed wrote

I assume that would be a receiver function. Can you provide details of
the lamp (systems) you're driving?

Is this over Wi-Fi, over mains, or some other transmission medium?

I can only guess you don't have a clue what you're talking about.

Bad assumption. The Philips Hue system does it using wifi and bluetooth.

I'd always thought (and I could well be very wrong!)

Yes you are.

that Hue lights (and other remote-control bulbs) communicated by signals
modulated onto the mains wiring, rather than by RF (wifi/bluetooth).

No they dont.

I suppose the acid test is to connect one bulb by a very long mains cable
so it is a long way from any other bulbs, and see if it can still be
controlled.

And you will find that it cant be.

And some of the lights and the movement sensors
particularly and the kinetic switches dont even have
a mains connection at all and still work fine.

I may be about to learn something... ;-)

Depends on how bad of a slow learner you are :-(

I suppose within a house, there is the reasonable assumption that every
bulb will be close enough to at least one other bulb that a daisy-chained
wireless communication method is always viable, even when the end-to-end
size of the area covered is large.

Yes, thats one of the brilliances of the system.
Not unique to Philips Hue, its Zigbee.

Does anyone know why Philips Hue still have a maximum of around 50-60
bulbs that can be controlled by one Hue logon (and maybe one Hue hub)?

Its a limit imposed by the hub, what it can handle. You need an extra
hub to exceed that limit. It isnt an absolute limit because it isnt the
number of slots involved, its how it uses its limited internal memory.

It's the one thing that customers are crying out for on the Philips forum,
especially with the increased use of a larger number of ceiling-mounted
GU10s to light a room rather than a much smaller number of brighter
omnidirectional bulbs.

Yep.

It's a shame there isn't a technology which allows a set of bulbs (defined
by their MAC address) to be controlled as a single unit (only consuming
one "unit" out of the 50-60).