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Multiplexing LOR outputs [an evil idea]


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QUESTION: Is anyone else multiplexing their LOR outputs?

EXAMPLE: Say that you have the following words that you'll want to individually control the letters for (but turn on no more than one of the phrases at a time):

MERRY CHRISTMAS [14 chars]
HAPPY NEW YEAR [12 chars]
HAPPY HOLIDAYS [13 chars]
JINGLE BELLS [11 chars]

To light each letter up in these would take 50 channels. Way too much. But if you multiplex it so where you have 1 line that indicates you want to control "MERRY CHRISTMAS", 1 line that indicates you want to control "HAPPY NEW YEAR", and so on, then you can individually (or simultaneously/identically) control the characters with 14 [characters] + 4 [lines] channels, making it only 18 channels.

Yes, if you wanted to throw a bit more hardware on it, you could potentially save two channels by having one of the four only accessable at a time, and with 2 line control channels (set as 00, 01, 10, or 11).

MY REAL QUESTION: Are there any pre-made relay devices out there that, if they receive 115vac on a control line, will pass 115vac (from a second input) through to another device? Or some more clever way of handling the hardware side of the multiplexing?

If somebody makes some not too expensive pre-made bricks that take two 115vac inputs and uses one side as a relay to pass the other side through, that'd be perfect.

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Sounds like a PLC would be your best bet for prebuilt. Use 4 lor outputs into the inputs of the PLC and control via binary coded decimal (BCD). LOR would become your encoder and the PLC would become your decoder.

If you are a DIY guy, you could use opto 22 G4 products for I/O and build your own processor with a PIC, basic stamp or BCD decoder chips.

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I guess what I'm looking for is more of a multiplexing hack using pre-built hardware pieces.

This may go back to my customer subtype. I'm technically skilled, and familiar with electronics (basic soldering, basic electronics), but I'll never trust myself directly tinkering with anything that has mains voltage, so I'd rather use pre-rolled hardware.

EDIT: The idea was to do the multiplexing through the LOR outputs, via switching plugs that would pass current through only if an additional line (the selector line) was triggered on with 115vac. I just don't think such a pre-rolled item exists.

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This has been discussed a few different times and I am looking to do the same thing. I have a set up in mind, but waiting for the LOR boards to test it out. Basically it is switching the neutrals with a triac. Few have suggested that you may get some back feed through the triac so a diode may also be required. I could let you know after I do some testing.

Chris

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The only way I can figure out how to do it might well cost as much as using LOR...

You'd need one 120vAC relay contact for each letter best way I can figure it. If you use relays with more than one set of contacts per relay, you decrease your relays by that many (2 per = 1/2 as many relays as letters, 3 per = 1/3 as many, etc.)

The coil side of the relays for all letters of message one would be tied together, and all controlled by one channel. The contact side of those relays should be placed in series with the supply circuit to each position in the message.

If you used channels 1-4 for messages 1-4 (let's call them rows) and channels 6-18 for the letters (let's call them columns), turning on channels 6-18 would do nothing until you turn on channel 1, 2, 3, or 4.

I don't know of a out of the box setup for this, but it doesn't seem too difficult to create. Just somewhat expensive. 120vAC relays with a quick search go for about $5-$7 US for DPST style. You'd need 25 of those. I guess it would still be cheaper, but still pretty pricey in my book.

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jmccorm wrote:

QUESTION: Is anyone else multiplexing their LOR outputs?




I have an idea using 9v. switching power packs to have certain LOR channels control my existing home made controllers to act differently.
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Unfortuately it is not as simple as it may sound. You can do it with DC using diodes, but on AC you will get current flowing thru the not yet on letter to neutral. You have to use a relay contact for each letter, and you could use 2 channels of LOR to drive one of 3 relays :

Control A and B BOTH off = no relay energised = Word D

Control A on & B off = relay A energergised = Word A

Control A off & B on = relay B energergised = Word B

Control A and B BOTH On = relay A&B energises relay C = Word C

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