spinning led display

PFloyd36069

Hi,

How would i make an object that would allow me to write the data for all the letters in the alphabet, then in my main program, be able to type in a message and let the object insert all the right data to make in show up on the display?

Thanks,

Bryan

CannibalRobotics

That's BIG! Start by figuring out your LED letter size. Most of the LCD displays achieve a nice character set with 8x5 or 9x5 pixel grids.
Are you starting from scratch or do you have the display already?

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PFloyd36069

i already have the display working with a single row of 7 led's spinning at about 300 rpm. i am trying to figure out an easier way to write the message, rather than having to go through and type the data every time i want to change what it says.

CannibalRobotics

What's the interface to the display?

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PFloyd36069

i have the 7 leds hooked up to pins 0..7 and i turn them on and off in certain sequences while they are spinning to make words.

CannibalRobotics

OK very cool!
I think I understand your question now. What you are saying is that you have to completely reload the prop program every time you want to change the message? Do you just want to hook the prop up to a keyboard directly?

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PFloyd36069

that would be sweet if i could but i have the whole prop spinning so i dont know kow i would hook it up.
even just being able to type the message into the program without having to mess with the byte%01110010 sort of lines would be nice

CannibalRobotics

What about an IR interface?

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PFloyd36069

i dont have an ir reciever or that would work

StefanL38

Hello PFloyd,

make your definition of the characters in a DAT-section in the same order as ASCII-code

Then you define a string like you would do it for using FullDuplexSerial with usual ASCII-code

make a repeat loop that goes through the string by using an index

from the ASCII-Code of a character you calculate the position of the pixel-definition inside the DAT-section

  'pseudocode 
  Adress_of_char := (ASCIIcode - OffsetValue) * NoOfBytesOfOneCharacter


  LED_On_Off_pattern := Pixels_of_char[noparse][[/noparse]Adress_of_char]


  'where OffsetValue is the difference between your first defined character and the ASCII-code
  'example beginning your pixeldef with "space" ASCII-code decimal 32
  'ASCII-Code - 32
  '"space" is your first character 
  ' "!" is second with ASCII-code 33   33-32=1 = second index in your DAT-section as index starts at zero

DAT
  Pixels_of_char long %0_0000_0000_0000_0000, ..... 'Definition of "Character "space"
                 long %0_0000_0000_0000_0000, ... 'Definition of "Character "!"
....

                 long %0_0000_0000_0000_0000, ... 'Definition of "Character "A"
                 long %0_0000_0000_0000_0000, ... 'Definition of "Character "B"
                 long %0_0000_0000_0000_0000, ... 'Definition of "Character "C"

'etc.

best regards

Stefan

Post Edited (StefanL38) : 10/26/2008 4:09:57 PM GMT

PFloyd36069

sorry for the brief description. I am not real good at the code part thats why asked for some advice... do it put the definition after the long%0_0000_0000_0000_0000, "HERE"

StefanL38

Hello PFloyd,

you can store different things in the DAT-section

the "%"-symbol indicates binary values a "$" would indicate hexadecimal

DAT
byte "E" would be translated from the compiler as ASCII-coded values

no your definition starts after the reserved word for the size
as there are byte or word or long

post your definition that you are currently using

if your characters would be a 8x8 dotmatrix

an "L" would be defined as shown below

(look at the pattern of all the "1"s

first for an easy view in separated lines.
By using curved brackets in that way for the compiler this looks like the second version below
The compiler "thinks" this is just one line

DAT
  DotMatrixPixel byte %10000000,{
                     }%10000000,{
                     }%10000000,{
                     }%10000000,{
                     }%10000000,{
                     }%10000000,{
                     }%10000000,{
                     }%11111111

'this is the way without curved brackets same function but harder to read

  DotMatrixPixel byte 10000000,10000000,10000000,10000000,10000000,10000000,10000000,11111111

or you start a new line always beginning with the size

DAT
  DotMatrixPixel2 byte 10000000
                  byte 10000000
                  byte 10000000
                  byte 10000000
                  byte 10000000
                  byte 10000000
                  byte 10000000
                  byte 11111111
                      

to explain a little more
the name "DotMatrixPixel" is free chosen by me
the "%" indicates the values following are defined BINARY
the comma separates the values from each other

best regards

Stefan

bdickens

Hey; I would love to see the hardware for this. I'm building one of these myself.
Thanks

PFloyd36069

well right now it is pretty crude...i have my prop with wires running all over, and it is zip tied to a floppy drive motor to spin it. if i can maybe ill post some pics.

PFloyd36069

here is one pic of it running.... my camera died right after i took this one because i had the exposure cranked a little.

RinksCustoms

according to the circular path differences, and the apparent angle of the camera, the green led is constant lit and on a lower plane than the red leds?

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Ken Peterson

PFloyd:· You might be able to transfer data to the prop using a serial connection·through an inductive loop.· Just put two loops of wire concentric to the spinning axis of the amature.· On the receiving end, you could perhaps send the signal through a schmitt trigger to square it up.

If I get some time later, I might provide a rough schematic.

BTW:· How are you getting power to the Prop in that configuration?

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Post Edited (Ken Peterson) : 10/28/2008 12:41:53 PM GMT

PFloyd36069

you are correct, the green led is lower than the red ones, because that it the power led on my demo board. i have the whole board along with a 9v battery zip tied to the motor.

Ken Peterson

Here's just a rough schematic of an idea to transfer data to a spinning Propeller.· I have not tested this.

After posting the picture, I realized I should have added a diode on the primary coil to take care of the spike, and possibly a current limiting resistor in series with the primary coil so you don't fry the transistor.· As I said, it's a rough schematic just so you get the idea.

·

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·"I have always wished that my computer would be as easy to use as my telephone.· My wish has come true.· I no longer know how to use my telephone."

- Bjarne Stroustrup

Post Edited (Ken Peterson) : 10/29/2008 1:40:26 PM GMT