Sending commands to NEXA switches faster

[nicwi]

Hi,

I am writing my own linux-based software for controlling lamps using NEXA switches and the tellstick duo.

Things seem to work as they should, but a problem is that the tellstick is _very_ slow at sending commands. It takes approximately one second per lamp command. This is annoying since I sometimes want to light up a larger number of lamps. It can take perhaps 10-20 seconds. In practice, such a system would not be accepted.

When using the NEXA remote controls, it is possible to control the switches much faster by just pressing the buttons. So there doesn't seem to be a fundamental limit in the radio protocol. The problem seems to be with the tellstick.

I have been looking a bit into the telldus-core source code and experimented a bit. Looking at the (incomplete?) protocol documentation at http://developer.telldus.com/doxygen/TellStick.html.

It is possible to tell the tellstick firmware to repeat a command a number of times, by prepending the 'R' prefix and a number. It seems that telldus-core (2.1.2) does not use this option.

So I experimented a bit with the repetition prefix. The smaller number of repetition, the lower delay. With R=1, the command delay is just above 100 ms, which feels acceptable. A problem is (as one might expect) that the reception become less reliable with a lower repetition. Sometimes the switches do not react to the commands. Most likely this is the reason for having five repetitions in the first place.

But, the remotes appear to operate fast without loss of reliability. So I experimented a bit more. My impression is that repetitions are only needed when no commands have been sent recently. When no radio commands have been transmitted for a while, the NEXA switches perhaps take some time to adjust to the transmissions before they can be reliably detected. Perhaps it is a matter of synchronization or level adjustment, or something else. I tried to modify the telldus-core to only repeat a command when no command has recently been transmitted. So far this seems to work relatively well, but more experimentation is needed.

If this works out well I could submit patches, if anyone is interested. But it would be good to hear what others are thinking, in particular the experts at Telldus.

Any thoughts?

Niclas Wiberg

[Schmeling]

Hi

I have excactly the same problem. I'm trying to make a NEXA on/off switch control some oter piece of electronics, and I need an on/off time of at most 0,5 seconds. Possibly less, which is impossible with the eventghost plugin and tellstick. I would never expect something like this to be a problem, and I agree. This is not acceptable.

So I would be very interested in seeing some development here.

Do you know if it is possible to send codes from Eventghost using this R prefix?