automatic digital controller!

[silvarblade]

i have a very simple question. what would u want your digital controller to do like control appliances by time or any other criteria

 

[blueroomelectronics]

What are you talking about?

 

[HarveyH42]

There is a comercial product line called X-10, been around 20-30 years, not the expensive from what I understand. Covers home automation and security pretty thoroughly... Might be with checking into, least you might get some specific ideas on what you want to do. Remote control, computer, timers, sensors...

On the web, there are dozens of site dedicated to home automation projects, some do-it-yourself, some selling (stuff). Home improvement sites also have automation projects.

Not really a big interest to me, be I run across these things often while looking for semi-related information.

 

[blueroomelectronics]

X10 is extremely unreliable but well documented. At one point I considered making a kit based on the X10 application note at Microchip (16F877 X10 controller)
Would have called it the Python as it could be dangerous.

 

[HarveyH42]

I've never used X-10, just know it's been around a long time, and some of the things they advertise. Wouldn't think their stuff is total crap, but no major competition either (think Microsoft Windows)...

 

[Nigel Goodwin]

I've never used X-10, just know it's been around a long time, and some of the things they advertise. Wouldn't think their stuff is total crap, but no major competition either (think Microsoft Windows)...

They weren't the first, but they were probably the only one who ever made a big push as a commercial product. Back in the 70's and 80's similar projects were all over the magazines - for a while it was the 'next big thing', but then it sort of faded away!.

 

[silvarblade]

a block daigram i madE!!

hey i have made a block diagram for my automatic digital controller and here are the few problems i am facing.

R represents 4 bit registers to store value of each second, minute and hour.
I have used a digital clock to count the duration for which the appliance will be turned on. The input time to the registers are converted in to BCD Code by the Encoder(74hc147). I will use a machine to compare both the registers so when the registers are same then it will send a signal to the relay to close of teh appliance. The problems are:

(1) How do i give the input to the time setting registers(R1....R6) so that i only use one encoder i-e the inputs are to be given in this format (HH MM SS) as soon as one enters one digit it automatically stores the next one in to the 2nd unit of hour. Any ideas.

(2) Which type of machine am i supposed to use to compare the registers. We have not started Machines yet but the project is due in a couple of weeks.

 

[BeeBop]

(1) How do i give the input to the time setting registers(R1....R6) so that i only use one encoder i-e the inputs are to be given in this format (HH MM SS) as soon as one enters one digit it automatically stores the next one in to the 2nd unit of hour. Any ideas.

Use tristate registers with enables; just enable the appropriate one and write to it.

(2) Which type of machine am i supposed to use to compare the registers. We have not started Machines yet but the project is due in a couple of weeks.

I think what you are after is a four bit magnitude comparitor. If I remember, 74xx85 is such an animal.

 

[silvarblade]

in magnitude comparator i will need to compare all the registers as individual bids rite as far as i have worked on comparators. a machine which i will learn ahead will compare two or more registers at a time rite or what? as far as teh tristate registers are concerned how do i get em to store data in the next one as soon as each digit is pressed?

 

[philba]

I strongly suggest you learn microcontrollers for this project. I'd bet your learning curve on the logic chips will be only slightly shorter than on a microcontroller. To top it off, you would get significantly more flexibility

By the way, X10 is around 95% reliable. while that might seem good. that means that 1 out of 20 events will fail which is simply not good enough for most people.

 

[Cry_Wolf]

well when a key is pressed a counter(name it 'A') counts. counter A is connected to decoder, the outputs of the decoder are the enable lines of the trisate registers.

Now lets start from the begining.

the counter A is initially 0 and the the first line of the decoder is high which is connected to the enable of the first register. Now when u press a key the value is stored in the first register, the counter increments and the decoder's second pin is now high i.e, the second trisate register is now enabled. Now when the key is pressed it is stored in the next register. .... and so on,.



Well i prefer u to use PiC or 8051 microcontroller. But if u cant then follow the steps listed above

 

[silvarblade]

hey i have just worked out the circuit it works in simulation of EWB i will post it in a couple of days.

 

[blueroomelectronics]

Take a look at Microchips AN236 which is a 16F877 based X10 controller with LCD etc...

 

[silvarblade]

here is it. EWB doesnt have 7485 so i will include them when i go hardware with it.

 

[blueroomelectronics]

Your schematic is not easy to understand. What are those boxes along the bottom of the schematic (hooked into the 7490)

 

[mneary]

Looks like a lot of effort just to avoid using a micro.

But, congratulations (if it works).

 

[Nigel Goodwin]

Looks like a lot of effort just to avoid using a micro.

But, congratulations (if it works).

Perhaps he couldn't find any valves/tubes to use?.

 

[silvarblade]

yeah it is working and i needed to avoid a micro because this was supposed to be a project on sequential circuit design. and it works.. at least in simulation.working on the hardware now