Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Pic 16f84a Rotating Led Display Circuit

Status
Not open for further replies.

Gayan Soyza

Active Member
I just want a program that displaying a word
when the circuit is rotating.same like propeller clock.

same this time also I used pic 16f84a.

I built the circuit and the rotating motor.circuit is ready to
use.need only the program. I wrote a simple program listed below

portB connected to leds.7 leds are connected in single column.

This is a very simple program I Wrote.In this case only the first letter
is displying well & the others hard to read.even i changed the delay.

I didn't use the call table method using RETLW...B cuz I dont know
how to do that.I Search in the web a simple program that displaying
a word all I found clocks in the web even i tried the MINIPOV.

Can anybody pls help me to do this Displaying a word using pic 16f84a..
 

Attachments

  • HELLO.txt
    493 bytes · Views: 2,250
you need a reference position before you display your letters because your motor rpm is not exactly the same with your software rpm :) that's why what you see are blurred letters
 
As stated I would think you need an input from the propeller to your pic chip to tell you when to run LETTERH (start writing to portB). It will sync the motor with your program.

Do you have a schematic or diagram of what you are trying to do? Also, I think there is a Bob Blick or close that has one on the next from way back when.
 
re Rotating LED Display pic 16f84a

penoy_balut said:
you need a reference position before you display your letters because your motor rpm is not exactly the same with your software rpm :) that's why what you see are blurred letters

Is my coding is wright? I dont have instruments to measure my motors rpm is it ok if I adjust some delay.I changed couple of delays but didn't work well..

delays i changed 0.3s,0.1s,0.009s......

How to get a reference possition???????
 
mramos1 said:
As stated I would think you need an input from the propeller to your pic chip to tell you when to run LETTERH (start writing to portB). It will sync the motor with your program.

Do you have a schematic or diagram of what you are trying to do? Also, I think there is a Bob Blick or close that has one on the next from way back when.

I want to run the program from the begining with the power supply on..
Hardware part is ok when u power it up the motor is rotating with the circuit.

circuit has 7 led's connected to portB (pic 16f84a)
same as bob blicks clock but i need to display a word not the time...."hello"
 
Gayan Soyza said:
Is my coding is wright? I dont have instruments to measure my motors rpm is it ok if I adjust some delay.I changed couple of delays but didn't work well..

delays i changed 0.3s,0.1s,0.009s......

How to get a reference possition???????

You need to generate a sync pulse from the mechanical rotation of the propeller - an LED and phototransistor could be used?.

The original version by Bob Blick used pulses from the motor brushes.

If you look closely at the source code, you'll see that the "dot rate" is adjusted to the speed of the motor to make the display a consistent width regardless of the motor's speed. The motor I used has brushes set 90 degrees apart, and gives two indexes each revolution.
 
Gayan Soyza said:
Is my coding is wright? I dont have instruments to measure my motors rpm is it ok if I adjust some delay.I changed couple of delays but didn't work well..

delays i changed 0.3s,0.1s,0.009s......

How to get a reference possition???????

its just a location in your display circumference, as Nigel said, a LED and phototransistor, when passing on a fixed reference, signals the beginning of outputting to port so your display would be consistent in its position.

in your hardware you have to add one input pin driven by phototransistor while in your code you have to test this pin before looping to display letter H

longer delay causes wider letter or even overlapping and vice versa
 
Ya Thats Right... Now I understood how to get a Reference point.
for this I will use IR sensor & a Ir bulb.

Each time when it passes the reference point it gives a signal to the pic & program gets run.....Before it comes to the reference point again the program must be end....I hope I'm right...any way thank u guys...now I'm trying to make.
 
i also want to make a rotating led display...
i hab planned to do it in a different way, i hab made a circular track with 7channel in it to get supply to the LED. i hab attached a foto of it...

I hab understood about the refrence point which we have to use.. what i dont understand is what time delay we need between the successive position of rotating LED i mean what is the appropriate speed of motor.. can any one tell me how fast moving object our brain can detect..

I hab read an article at Wikipedia.com and found that the presistance of vision is 25th of a second....
i hab planned to use AT89s51 microcontroller. M not going to place microcontroller on the rotating disc rather it i'll be placed separate.......

can any one suggest me some idea about this topic..

>>santosh gairhe
 

Attachments

  • 091001-000605.jpg
    091001-000605.jpg
    36.9 KB · Views: 1,525
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top