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16 to 4

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svtiss

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Hi
Here is a part of my project, I have 16 buttons or switches in one room and in other room (main room ) I want to know which buttons is pressed , but I limit on amount of wires , can I use only 4 wires (for data) and send data though .
I am sure how to change decimal to binary code ?
Thanks
 
Hi
Here is a part of my project, I have 16 buttons or switches in one room and in other room (main room ) I want to know which buttons is pressed , but I limit on amount of wires , can I use only 4 wires (for data) and send data though .
I am sure how to change decimal to binary code ?
Thanks

hi,
Use two HEF4532B 8 input priority encoders and a HEF4071B .OK

Get the datasheet for the HEF here: Datasheet & Application Note Database, PDF, Circuits, Datasheets | Datasheet Archive
 
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why not just a simple 74154 4 to 16 multiplexer?
maybe easier but then the distance between?
if just wanting a two digit display then I think a 74194??
 
74154

This IC have 4 binary inputs to 16 output I can use this as the end of the line ,
but I am looking for transmitter 16 to 4 .
 
74154

This IC have 4 binary inputs to 16 output I can use this as the end of the line ,
but I am looking for transmitter 16 to 4 .

hi Deb,
The 74L154 requires a 4 digit address in order to select 1line to 16 lines, its NOT suitable.



hi svtiss.
You could make up a 16 to 4 using a mass of diodes, but it would be messy.:)
 
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Using the 74154 you run 4 wires to each switch
better idea is to use a PIC (microcontroller)
piece of cake for this usage.
don't think the code would be all that hard either. you still need at least two wires to each of the 16 switches.
am sure some one could write a code snippet for you, program the chip and send it to you.
have several ideas on method to do this.
output to an LCD display telling which switch is thrown on. and time of switch closure could even be included.
thinking a 1-wire code similar to using a ds18b20 temp sensor Swordfish Tutorial - DS18B20 Temperature Sensor but might be easier to just connect each switch to an input. easier??
 
Try "Allied Electronics".

Is it necessary that the the 4 wire signal being sent to the main room be continuous, I mean, would it
matter if the signal being sent oscillates at a rapid rate? As a last measure, maybe you could still utilize
the 74154. Have each 74154 output go to a switch, and a "common" from all switches coming back to 4
7408 AND gates, whose other inputs are the 7490/74154 binary link, then send the AND gate outputs...
555 the 7490/74154 to "sample" each switch for continuity, and when present, it will trip the ANDs (that
apply per the binary 7490/74154 link). Start the 555 at a slower rate and increase it's speed until you
develop problems, then back off the timer (maybe about 10%). If you need a long transmission line,
then use some transistors to increase the voltage sent on your four wires. One good thing about this
circuit is, you could reverse this entire process on the receiving end and indicate more than one switch
being activated (inputs to the 74154) and it would tell you all of the switches that are activated. If need
be (for a continuous signal, or if the timer has to run at a lower rate than ideal <causes your LEDs? to
flash>, buffer each 74154 receiving output with some capacitors to hold the monitor high long enough
for the next received sampled signal). Just an idear...
 
Using the 74154 you run 4 wires to each switch

hi deb,
Not wishing to sound a little 'picky', but could you explain this method of connecting 16 input wires to 4 output wires using a 74LS154.????
 
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yes I got the scheme backwards.
I was thinking 4 wires ionto 16 not 16 into 4
do it with a PIC
 
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