PIC Oscilloscope Clock

For those are not into electronics, you must know that an oscilloscope has basically only one timebase to move the spot horizontally from left to right with the same intensity. The vertical deviation is function to the input voltage. You understand immediately that you can't directly display 7 segment digits, because you can't move the spot from right to left.



By using X/Y mode, where the spot is controlled on two axes by two different voltages, it is possible to draw a picture (as in the examples mentioned above), but a fast digital to analog converter with two channels and at least 8 bits of resolution would be needed.

So we have to deal with a spot that always goes from left to right in the same period of time.
If we want to have a 7segment-like display, we have to draw :

vertical segments : easy to do, just change voltage up and down quickly a few times.
horizontal segments : easy to do, just set a voltage level and keep it as long as you need.

By using 2 PIC outputs and a basic R2R digital to analog converter, we can have up to four different voltage levels : 3 for the vertical segment, and another one where to put the spot when it is not in use to draw a segment.

But the problem is that a 7 segment digit may have up to 3 horizontal lines at a time (like 2, 3, 8, 9..) but we can draw only one during one spot deviation.
So we will have to cheat with retinal persistence and use multiple frames : since we can have only one vertical segment per period, three periods will be needed to draw a full 7 segment digit.

Supposing we want to display 12:34:56 on the screen :

During the first period, we will draw all vertical segments, and horizontal upper segments only :

As a game, I let you try to find out the spot trajectory.
Don't forget the rules :

you can't go backward
you can't clear the spot

But you can move so fast vertically that the eye can't see the spot moving.

The lowest line under the digits is not significant, it his the place where the spot is parked when not used to draw a segment.

Schematic Diagram:






Working Video



for more details see this LINK
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Conversation

Sun May 20 2018, 10:01 AM
justinb
how to write and execute a program that read the keypad button and display the number on 7 segment on intel8051 at89s52 in assembly language?
Thu May 17 2018, 06:36 AM
HAMZA TAJ
sir iwant to ask about controller of three phase supply by using back to back thyristor instead of triac....will u give me some guideline?
Sat Apr 28 2018, 12:54 PM
ashutosh jain
IR Remote Switch using TV remote (RC5 Protocol) is not working properly. opp1 & opp2 is in problem.plz help
ExperimenterUK
Fri Apr 27 2018, 08:09 PM
@kaiserslautern Post in forum
Wed Apr 25 2018, 07:09 AM
kaiserslautern
Hello everyone, using software uart is a very good idea for a second serial port. Thank you so much. I would kindly like to know how to connect this port to the PC?
ExperimenterUK
Sat Apr 21 2018, 07:50 PM
This is a community site. Feel free to help anyone needing advice
hareeshchamiyar
Thu Mar 29 2018, 10:47 AM
please help me for the configuration bits for dspic30f2010
hareeshchamiyar
Thu Mar 29 2018, 10:45 AM
can any one using dspic30f2010.
Thu Mar 29 2018, 06:03 AM
Neena
can anybody give solar tracking in 8051 using proteus and keil to mail [email protected]
ExperimenterUK
Mon Mar 19 2018, 07:33 PM
sorry bedo.. maybe next time

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bdmehta
Tue May 22 2018, 02:30 AM
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Sun Apr 29 2018, 07:09 PM
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Sat Apr 28 2018, 12:41 PM
pirpiri
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Pater
Fri Apr 20 2018, 02:38 PM
jamiel
Sat Apr 14 2018, 12:47 AM
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Mon Apr 02 2018, 06:27 AM

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ExperimenterUK Avatar
Posted By ExperimenterUK
Sat Jun 16 2018, 11:33 PM
hi sir sorry for the late reply sir can we control...
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Posted By LAMBO
Sat Jun 16 2018, 07:15 AM
hi sir sorry for the late reply sir can we control...
ExperimenterUK Avatar
Posted By ExperimenterUK
Mon May 14 2018, 10:17 PM
So the main problem is that I am not getting Analo...
ExperimenterUK Avatar
Posted By ExperimenterUK
Mon May 14 2018, 09:40 PM
Hi sir after checking all the connection i...
Pater Avatar
Posted By Pater
Mon May 14 2018, 05:36 PM
Basically my project is based on Data Acquisition ...
LAMBO Avatar
Posted By LAMBO
Sun May 13 2018, 02:13 PM
Hi sir after checking all the connection i...
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Posted By ExperimenterUK
Mon May 07 2018, 07:27 PM
This design should be fine.Choose a frequency betw...
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Posted By Pater
Mon May 07 2018, 01:28 PM
Sorry for late reply as exams were on,Based on my ...
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Posted By ExperimenterUK
Thu May 03 2018, 03:32 PM
If the circuit works with a light bulb, the probl...
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Posted By LAMBO
Thu May 03 2018, 08:04 AM
Hi sir as u mentioned above everthing is working...