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Thank you ,
I am not good with PIC`s ,
I need time to learn the basic theory of PIC , but have no time ,
I`l think it over and thanks again
with alot less parts
I was thinking along the lines of just using either 8 input pins or 16. sixteen would make for a very simple PIC program. Just poll all 16 inputs and which ever one goes LOW then display the switch number using an LCD or multi digit LED display. I oped for the LCD
wouldn't be much to add a time of switch closing routine as well?
an experienced programmer = about 20 miniutes?
the schmitt trigger inputs to prevent switch bounce as the switches are a distance away. A cmos version? unless 74C14
one PIC, 16 N/O pushbuttons, 3-7416's, a 5 pin header (not really needed but?, about 20 resistors, a diode and a well regulated 5volt power supply. A wall wart would do the deed but use a regulator anyway.
whole setup less enclosures about $20
the LCD could be a 16 x 2 =$6
the PIC chip can be had for FREE or under $5
a perf board unless a custom pcboard (am in process of designing very similar for a tempeature sensing unit)
The hard part is the 40 pins to deal with on a perf board. much easier using a pc board with header plugs to keep things straight.
Lets see if I got this right=16 seperate switches in 16 different locations. two wires to each switch.
am contemplating a one wire scheem. I wonder if Maxium has such a beast?
I might be wrong but if he uses a one wire set up then all the switches can be bussed on one wire (plus Vcc and Grd.
depends on amount of money the op wants to spend.
another solution is to use diodes or gates to make ones own 4 bit coded switches
switch 1 = 1000, switch two = 0100 etc. then the problem comes in if two switches are closed at the same time = really top level confusion for sure.
another solution would be DTMF (think telephone)
this might even be the easiest to implement??
using ONLY 4 wires --can be done just how much cost.
I'm still not really understanding your idea. You could use 4 wires each as one bit but that wouldn't handle multiple pushbuttons simultaneously and you would require a seperate power supply in the other room. This is what I had in mind:
View attachment 38149
There's 2 PICs each less than $2, 8 resistors mayby .05 each, the LCD, and the pushbuttons. In the finished circuit you'd need a few caps here and there and maybe some pull up resistors on the I2C lines but that's about it.
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I am not good with PIC`s ,
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Does the 4 wires include ground? If so, a 16 to 4 encoder won't work as you'll need 5 wires in total. You could link a couple of shift registers and send the data serially with 4 wires (clock, data, reset & ground). but, as mentioned earlier, a couple of PICs would work the best because you can add error and fault correction easily.but I limit on amount of wires , can I use only 4 wires (for data) and send data though .
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Post #33 by mikemi if more than one switch is pressed then you have two or more resistors in parallel which could cause a false switch indicator...
several problems
in post #30 by vn147 I count 8 wires to the switches