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Re: Re: Serial protocol questions
I have to tell you I didn't think there would be such a fire storm of
conversation about this.
This is good stuff!!!
So lets talk system layout. I sounds like there should be master hardware
that interfaces with a PC. Agreed?
We need to determine functionality of that master, serial protocol to the
PC, then RS485 protocol to the slaves. Ideas?
I really think we should keep the RS485 speed down around 9600. This will
allow people to develop on slower pics. I rarely cheap beyond that point.
----- Original Message -----
From: "g8kmh" <lehane@xxxxxxx>
To: <ukha_xpl@xxxxxxx>
Sent: Monday, January 24, 2005 7:46 AM
Subject: [ukha_xpl] Re: Serial protocol questions
>
>
> I've dropped my response in below.
>
> Lehane
>
> --- In ukha_xpl@xxxxxxx, "Neil Wrightson" <neilw@n...>
wrote:
>> Hi Guys,
>>
>> 1) I'm all for a combined project.
>>
>> 2) I don't want to start another mine is better than yours
> discussion, but,
>> I use AVR's :) I have a great compiler AVRCo with true
multitasking
> etc
>
> To some extent it is irrelevent to most end-users. Few are going to
> change code, some will want prog'ed devices and most a kit (or at
> least PCB and CPU).
>
> The protocol outline is doable across a wide range of devices, indeed
> it needs to be interoperable.
>
>>
>> 3) I think that a dedicated 485 network controller will be
> required. I think
>> the 485 comms will probably run about 38400 baud.
>> A 16MHz AVR will happily look after this.
>> The network controller will pass and receive all state changes
> to the PC
>> as well as heart beats for each device.
>> Comms to the PC could be 9600.
>>
>
> A separate controller has some advantages of redundancy and
> interfacing with Win* or *nix.
>
> With xPL not on the wire then heartbeats can be different internally
> to externally.
>
> Presumably the host software will do the device/instance id->node
> number conversion and the device/instance config?
>
>
>> 4) I envisage that there be at least two types of room controllers
> (Perhaps
>> we should start by settling on some names for these things)
>> a) Bedroom/kitchen/Living area Controller wish list
>> Display,
>> Personnel Switches for lights, sound muting etc,
>> Data entry method, Set room alarm clock time etc Sleep
time
> for
>> lighting etc
>> IR Transmitter, Turn telly off when I fall asleep in bed,
> turn
>> ceiling fan off etc etc
>> Personal ID method
>> Sound
>> Movement sensor interface
>> Switch inputs for door & window reed switches
>>
>> b) Basic room as in garage/toilet/bathroom wish list
>> Personnel Switches for lights etc,
>> Sound
>> Movement sensor interface
>> Switch inputs for door & window reed switches
>> Note - This is to be a cheaper version, no display only
> beeper for
>> sound alerts, maybe a IR receiver for configuration ??
>>
>> Hardware Solutions for above
>> Display,
>> 16*2 LCD with LED backlight OR maybe a small graphic LCD, could
> display
>> small icons for
>>
>> you have email, voice messages, phone callers etc.
>> Personnel Switches for lights
> etc, 2..4
>> Tactile switches I.e. small PCB mount
>> Light Control
>> either 240V relay or triac, triac allows dimming, great for those
> wee stops
>> in the night
>> Data entry method,
>> Universal TV remote. I can currently decode Sony or RC5 signals
>> IR Transmitter
>> IR led on controller as well as capability to add an external IR
> led else
>> where in the room
>>
>> for better coverage if needed, I.e. Living room with external LED
> for Stereo
>> etc.
>> Personal ID method
>> Dallas 1 wire ibutton, A lot cheaper & smaller than RFID!
>> Sound
>> 2 Types, 1) Standard beeper. 2) Optional 1W speaker with sound
> relaying from
>> controller Pc
>>
>> Probably a separate optional PCB.
>> Movement sensor
> interface As
>> suggested either a integrated unit actually on the controller or a
> separate
>> security PIR
>> Switch inputs for door & window reed switches
> Standard style
>> of inputs on a micro 5..12V tolerant.
>>
>> Power Supply and Signal
>> I suggest that we use CAT5
>> Power - 2 Pairs 1 pair for 0V and one pair for +24V.
>> Comms Signal - 1 Pair
>> Audio from PC - 1 Pair
>> If we try to use the standard pin outs for power over
> Ethernet
>> and data signals, nothing will be damaged if
>> a wrong device is plugged in somewhere.
>> Although, I did see these devices as being panel
> mounted on the
>> walls.
>>
> Mmm!
> I'd caution against making the devices too complex. Better have 10
> types (smaller/cheaper) than 1 do-everything and they are likely to
> see the light of day faster. You can always put two/three/four in one
> box.
> So I'd go for:
> 1 n-way DC input (maybe analog) variations can include on/off,
> momentary, dimmer action, etc.
> 2 n-way DC output (maybe PWM on some for LED's) variations - opto,
> SSR, etc
> 3 LCD display driver
> 4 RFID (...and RFID to me is EPC/ISO 18000)
> 5 Universal IR (UIRT on 485)
> 6 Dallas touch and/or one wire sensors
> 7 MSR (Track 1/2/3)
> 8 Bar Code Reader (UPC/EAN/ITF/Code 39)
> 9 Analog input/output (0-5/10V)
> 10 ....
>
> Agree on the power to the unit, although 12-15V maybe sufficient as
> the power consumption is going to be pretty low on most.
> Not sure about the audio..I think that belongs on Ethernet in the
> digital domain. I guess you're looking at voice/audio feedback but
> would you want output from every device? Or would you command each
> amp on?
>
>
>
>
>
>
>
>
> xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
> http://www.xpl.myby.co.uk
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