RE: Re: Honeywell Smartfit research and the start of a generic interface (wish me luck!)

["Ian Davidson" <ian@xxxxxxx>]

Hi

> There's a pair of tiny 433MHz modules (TWS-434a) on my desk for a
> future project!

I small warning to anyone going the wireless route. The UHF band is
changing which means many commercial high power base stations will be
moving to the 430Mhz region. If you happen to operate any low power
devices in the close vicinity the receiver will get swamped and your
system will not work correctly. Generally the cheaper the module the
worse the selectivity of the receiver. Although the changes are
technically a few years away my company last week installed three
transmitters as the first UK test of one part of the new spectrum. Yes
this will make the car fob situation very much worse.


> When I get that far, my own ancient attempt (Distributed Automation
> Protocol) is toast as other more promising protocols are out there.
> xAP and xPL are just two that look good, although a lighter binary
> protocols with error correction might be needed for RF (SNAP?
> http://www.hth.com/snap/).

My own designs are based on the SNAP protocol. It is quite flexible to
allow for future enhancements. Below is a copy of some of the commands I
use to date. I'll try and post a few more details at a later date as the
list is a little out of date and doesn't cover the status response and
switch functions. Another quick note it appears that SNAP is no longer
promoted although that in no way affects its use as a simple and quick
protocol.

Command Byte	Description
00	xx	xx	xx	Switch Off unit
01	xx	xx	xx	Switch On unit
02	yy	xx	xx	Dim by yy% range 1% to 100%
03	yy	xx	xx	Bright by yy% range 1% to 100%
04	yy	xx	xx	Goto level yy range 0 to 255
05	yy	xx	xx	Rate of change yy range 0 to 65535
06	yy	xx	xx	Goto scene yy range 0 to 4
07	aa	bb	cc	Change switch ID to aa bb cc - max - mid
- low bytes
08	yy	yy	xx	Change switch on commands to yy yy
09	yy	yy	xx	Change switch off commands to yy yy
10	aa	bb	cc	Change Main ID to aa bb cc - max - mid -
low bytes
11	aa	bb	cc	Change Group ID 1 to aa bb cc - max -
mid - low bytes
12	aa	bb	cc	Change Group ID 2 to aa bb cc - max -
mid - low bytes
13	aa	bb	cc	Change Group ID 3 to aa bb cc - max -
mid - low bytes
14	aa	bb	cc	Change Group ID 4 to aa bb cc - max -
mid - low bytes
15	aa	bb	cc	Change Group ID 5 to aa bb cc - max -
mid - low bytes
16	aa	bb	cc	Change Group ID 6 to aa bb cc - max -
mid - low bytes
17	aa	bb	cc	Change Group ID 7 to aa bb cc - max -
mid - low bytes
18	aa	bb	cc	Change Group ID 8 to aa bb cc - max -
mid - low bytes
19	aa	bb	cc	Change Group ID 9 to aa bb cc - max -
mid - low bytes
20	aa	bb	cc	Change Group ID 10 to aa bb cc - max -
mid - low bytes
21	yy	yy	xx	Change scene 0 to yy level yy rate
22	yy	yy	xx	Change scene 1 to yy level yy rate
23	yy	yy	xx	Change scene 2 to yy level yy rate
24	yy	yy	xx	Change scene 3 to yy level yy rate
25	yy	yy	xx	Change scene 4 to yy level yy rate

I am currently moving some of the change value commands higher up to
allow the lower codes to have more flexibility. I should have the first
software finished in about three weeks, depending on a work project
that's taken on some urgency.
>
> Have you read about the commercial Z-Wave? (http://www.zen-sys.com/)
>
I have signed a NDA and looked at this. It is good to see new movement
in the HA scene but I decided for a few reasons to go a separate path.

> Proton+ BASIC doesn't seem able to do interrupt routines making
> watching two asynchronus interfaces 'interesting'. I'd prefer not to
> invent another standard, though.
There is support for interrupts, both normal hardware and a more basic
(slower) software interrupt. Personally I always write my ISR's in asm,
but again Proton+ handles mixed basic and asm. They have just launched
version 2.1 which is much improved and very good. They have a forum if
you want to browse or ask questions.

Hope some of that helps a little.

Ian D.