Re: Talking to external hardware
Re: Talking to external hardware
- Subject: Re: Talking to external hardware
- From: "TRELEAVEN, CRAIG" <email@hidden>
- Date: Fri, 11 May 2001 09:16:50 -0400
- Organization: Clearview Consulting on assignment at Bell Nexxia
You might want to check the comp.home.automation newsgroup.
http://groups.google.com/groups?hl=en&lr=&safe=off&group=comp.home.automation
The interfacing bit sounds like something that they'd jump on. Not many Mac
folk, though. In fact, I'm not sure it is a good project for a Mac
controller but that depends more on your requirements. I imagine latency
could be an issue. With a serial interface, there will be a non-trivial
delay before your system will respond to changes in conditions. X10
transmission just makes things even slower.
A leading Mac-based home automation product is XTension.
http://www.shed.com/
The developer has a lively mailing list with some seriously technical folks.
Perhaps they could give you some pointers.
BTW, my vote for most reliable Mac configuration is an SE/30 running 7.5.3 or
7.6.1. I worked in a small department where one acted as a file server,
Laserwriter bridge, fax machine and general 'extra' Mac. It would go for
months at a time without a reboot.
Craig Treleaven
Sun Real wrote:
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Greetings,
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I need to control the operation of some relays for a small scale power
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distribution system & I want to do the programming, err, I mean
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scripting, with AS if I can.
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There is a power source - a micro-hydro turbine - and 8 circuits to be
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supplied from it. The output from the turbine varies over a large range
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(50-1500W) as do the loads, which can be anywhere from nothing to more
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than the total output.
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My task is to distribute this power - connect and disconnect the supply
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to each house - according to certain rules. (In case anyone's wondering,
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the houses each have their own battery bank. They don't lose power,
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their battery chargers switch off until it's their turn again.)
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I will receive magnitude information (a continuously varying voltage,
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analogous to the power being used) from current sensors and, depending on
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this & the program logic, send on/off commands to some of the outputs
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(the relays).
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My limited study of the X-10 system indicates that I could probably get
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it to do some of what I want but the switch modules are prohibitively
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expensive in Australia & it doesn't look quite right for this.
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I figure I could use the 'Serial Port Commands' osax to get data to &
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from my script & guess I can build a box to interface between this and
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the relays if necessary, but I'm also wondering if anyone has any bright
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ideas of any kind.
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For example, does anyone know of any ready made chips or modules I can
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buy that do standard interface stuff for/with serial data, like taking a
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varying voltage input and converting it to serial data I can handle on
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the Mac? If not, where do I start studying so I can build such a thing?
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What chips deal with this kind of stuff? Is it a job for a micro?
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I also need to try to determine what my minimum Mac hardware spec & AS
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version should be. This thing will have to run 24/7 and won't be all
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that close by, so the requirements are reliability and reliability.
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Any help would be appreciated. I got 'volunteered' for this and am a bit
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stuck as to where to start.
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Cheers,
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Richard Morton
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-- Great Lies of the Music Business: "I'm with the band"