Multi-CLD

[Agashka]

Hello guys , I got that project , witch i am thinking on , witch is , do a multi-LCD , a LCD that would show Time, and CPU degrees.

Ok, Here the probleme, one LCD of 4 digit gonna be used , that i took from a Alarm Clock.The thing , is that it got 21 input pins and 1 output. Since i cant display both in same time , i thought at: mading a switch that would switch the Time off then CPU Temp on. But thats almosty impossible! i would ave to do 21 switches to switch all Time's input off , then 21 switches for CPU Temp on....


ok , im a little verry noob on electronic , and i dont really know how do a such device(the switching device) so i ask your help

ah also , my first thought was to put a switch on the main circuit of the Time , but it would reset the time each time...


if someone understand what i just say and able to help me , pls!! reply , cauz i am french and im really poor when it come to explain something

 

[murdok5]

Well, if I am reading this correclty, i dont think a switch will work. Also, your display sounds like 4-7seg LEDs, which sounds about right.

For a class, we had to design, build, test, and program an alarmclock radio from SCRATCH (resistors, transistors, etc). It is very easy if you use a uController, but getting this to interface with your PC for temps will be a pain.

Your code would determin what is displayed, and when. This can be tied to a button, thus no need for "switches." How the 7seg LED displays that I have used work is there are 7 inputs, one for each segment. There are then 4 outputs, one for each DIGIT. You apply a current to the various pins (segments) that you wan tto light up. Then you sink that current on the output of the digit you want to show. You continue this pattern for all 4, thus they are NEVER on at the same time. This happens fast enough that we dont see it. (Note: i am ignoring the colon, and any other eraneous pins that might be present).

I would suggest looking for a datasheet on the LED display. Here is one that i used in my class that may be of some help (see page 3):

http://web.engr.oregonstate.edu/~traylor/ece473/data_sheets/MSQC4911C.pdf

hope this gives you some better info