How to Design a Keyboard Editable Running Message Signboard for Embedded Projects?

Hello all, I'm a friend from Africa (Nigaria).
I'm in to embedded design as a beginner and I succeeded in designing a lot due to the assistance I got from this forum, through others questions/answers thank you all.

Today I found myself with a big challenge in the field for which I hope getting the solution from this talented forum.

I came across a running message signboard which is keyboard editable and I want to make one but I search for literatures, none give me an inside on this design as usual.

Kindly, prove me right, to have the everlasting solution from this our forum.

I will be expecting any feedback that may help.

Engr. M. J. Musa

Ready to use project: "Your text to link here...(Running text + keyboard)":http://cxem.net/mc/mc150.php

@eugene, thank you very much for your effort to assist me.
But I can't understand the language of your attached because is not in English.
I really appreciate and I'm looking forward for any alternative.

Engr. M. J. Musa

Overhere is schematic diagram with the english remarks. Also sources of firmware whe are remarked sprites of symbols. You need only _redraw_ sprites to Latin symbols (at this moment sprites for the Russian symbols).

See the example how to redraw Russian symbols to the English symbols

Hi musa Im also from africa ( South Africa lived all over South Africa )

First of all need to know what the interface is to your sign Im assuming youve powered this up have seen something come up on the display Possibey opened this up had a look inside and would hopefully have made a list identifying various IC numbers You might have downloaded some datasheets and will have identified a port of sorts

If you havent lets start with that first otherwise we dont have any idea of how to interface, what protocol to use to talk to the display and how we write software to write to ram locations if there is any ram or how to write to addresses on the display

So lets start with the hardware and perhaps you might upload any data that you have so far model number make anything that might help us so we an look at probability of talking to display and writing a front end to talk to display

Photos could be usefull too

Thank you Engr. Mark.
Your suggestion is perfect, I'm all yours waiting for the next step.
Pls. Put me through.

Engr. Muazu

Thank you very much for shading the light Eugene.
I'm grateful.

Upload your data lets see what you have to hand so I can examine what the possibilities are

Engr. Mark,

I want to display this an information like this.

"Welcome to HEF
Know your HIV status? 
Goto any nearest HCT centre. 
Stigma kills, do not discriminate against HIV positive people.
Prevention of mother to child transmission of HIV/AIDS."

I will be expecting your reply.

No problem with what you want to display You can make this scrolling message The issue mussa is I need to see your data sheets and photos of hardware that you have at the moment so that if we can do this then I can start writing up a software front end solution to do what you want so that you plug your pc into the port type your message hit a button and bingo up comes your message

Controlled via RS-232C (COM-port) Scrolling Text. Sources + Project in Proteus.

Hi eugene Hes found a message bourd In other words he has one ready made what he doesent seem to have are the schematic or component lists, memory maps etc Thats what im waiting for him to upload He want software to talk to his signbourd he already has

I see you use proteus Do me a favour would you check to see if you can get a cmos crystal controlled oscillater to work also a colpits oscillator an astable multivibrator and hartleys oscillator to work

My version I have is ver 7.6 service pack 4 on xp


could you let me know what your findings are please cheers

Engr. Mark,

I think I contra explain what I need.

I'm trying to say that, I saw a keyboard editable running message display, not that I have any.

I will be glad to have a help as usual from the potential members of this forum.

Pls. Mark I need both:

Circuit and Code
To study and make one out of it.

I will be glad to read from you again

Engr. M. J. Musa

Engr. Mark,

I'm good in designing circuits, but I'm sure with experts
like you, Engr. Eugenes and others I can be morethan I'm.

Engr. Eugenes cct. was self explanotory.
The attached proteus and the source codes are as well good.

1. What are the remaining process to do after the hardware
and software work?
2. what may I pls. click to start writing from my PC to the
hardware?
3. how may I deleat a message and restore another?

kindly explain.

Engr. M. J. Musa

HAVE a look at eugenes hardware first of all then tell me if you understand it

Next do you whish to understand how this is done or do you want just simply to build this and have someone create the front end for you

Do want to learn how programe the mico i.e the hardware with memory as you will need memory

This will mean upgrade processor add memory as well to Eugenes hardware thats If you intend to store messages on the signs electronics itself

THIS means attach a laptop write your messages to the sign, remove laptop and sign does the rest of the work for you


Do you intend this to iterate through all messages and loop


Finally do want to learn how to program the front end i.e how you actually go about writing the software

Do you understand the different types of comminication protocols used what is your level of understanding

Do you also undersand the different types of bus used i.e spi interface, serial interface

What is your level of understanding of the above


One more point if you do want to study this

How long do you think this type of project takes from start to finish in other words what do you think might be the timespan for something like this might be pcbs electronics coding front end coding debugging etc etc

I nearly forgot Here is a pdf version of Eugenes schematic
Also do you know how to blow the main cpu if we say wrote the code for you and do you have any understanding of how to make the pcb's or would you want these shipped to you

What do you expect to pay for hardware etc for the R and D, research and development etc I just want to get some feedback so that I have an idea of how we can achieve this for you sensibly


There may be other question I might have ommited so if you can go away and think about this then get back to me



Cheers Mark

Thank you a lot Engr.

Engr. Eugene,

This is wonderful.
I hardly bileave of what I received as attached, you are good.

May I pls. have the proteus again? the attached does not open on my proteus 7.0. pls. advice.

So you understand the circuit Thats a good start
You have done some some design works thats another big plus

What about printed circuit boards you havent told me you make these yet?

What about the code Do you understand the asm? ?

Important this question I cant code in full when it comes to asm I can do a fair amount but its easier to do this in c or in proton basic

The methods are written for you so it makes a massive difference to time Which is always important

Next we need to upgrade that design so we can incorperate memory other wise we going to run out of space when we include character maps which need to be built in so as to clock the data out onto the 8 BY 8 LED matrix's dependant on your strings which you are going to send to your controller board

SIZE of 8by8 Matrix?

Do you want stock standard matrix or do you want to build your own matrix, up to you this one

Best way to handle this is on a modular basis

Can you erase message you ask?

Yes we re write to random access memory hence why we upgrade the original circuit to include serial eeprom using I2C bus


What can you use for software

MPLabs ide

I use ver 8.70 download from www.microchip.com but that is down to my programmer plus of course I have c compilers plus basic compilers which I prefer at the moment anyway but thats also due to finances which are limiting factors as they always are

Front end? Im suggesting write a new one

You can use for ease of use, Java which is free for download but if you do use this then you will need to download javaxcomm api as well, I have a funney feeling that has now changed plus install this and you will also need netbeans which is what I use www.netbeans.org for java development or you might whish to use oracles. Ide instead which is called JDeveloper You will have to play a bit to find out which one you can personally work with I use both Some things i prefer on Jdeveloper than i do on netbeans and visa versa

Make sure your pc is up to date as well that has got a lot to do with compiling etc plus memory of course

Oh yes good this isnt it, lovley jublee

JAVA SDK you can obtain from www.oracle.com

If you are really good at visual c plus plus then opt for codeblocks www.codeblock.org.

BUT you will need to also download and install gcc toolchain possibly the gtk package as well

All sounds easy this untill you have to do this and it can be a real headache make no mistake even just getting the installations to work nevermind coding

If your going to use c plus plus I hope you know how to work with DCB structures, whoo hoo mercy berku

If your not then opt for what I said and thats oracles java, advantage here is networking using the net classes

Might want that later and whats more dont have to recompile to run on unix,posix,linux or windows os

You can create a smashing visual interface with this anyway using the lightweight classes

Up to you again

Or you can opt for dot net in which case there is the vs2005 free download I believe from micrsoft

Or you can use simple plain visual basic ver 6 proffesional from microsoft Howevere you will have to watch out for compatibility issues with windows 8 and 7 in conjunction with vs2005, 2006,2007 up to now I believe 2012.

Said this is not easy anymore especially keeping up to date with modern trends nevermind electronics industry Changes are that rapid now

or you could opt for Borlands delphi might be easier for you but what a price you will pay for this developement path


Again this is personall preference

Plus i have another little idea here as well but cant comment just yet because Im waiting for delivery to arrive so not saying to much untill it does and Ive investigated this a bit further

Thats quite a bit to take in This is practically final year uni stuff my friend Very difficult to learn or do on your own you know I hope you understand this

Bare in mind ive been teaching myself all of the net for at least 15 years if you can master 20 percent of what ive just talked about plus embedded devices plus webpage technology Your not doing to bad at all plus vba plus office plus all your art packages

Then your a bloody genius and im 50 still learning new subjects everyday

Theres some more examples if you want to see this is done but thats without a front end so theres lots of work to be done here without the research to make this All fit together

http://blog.vinu.co.in/2011/07/10x8-led-dotmatrix-display.html?m=1

What have you noticed about the schematic look carefully after looking at the link above and tell me what you can see that springs to mind?

Something to do with the way the data is shifted in and out If you were going to scoll text which side do you start from? Which column?

There you go if you fancy making up your own 5 by 7 matrix led modules here is the display output board you will be able to sell this just on thier own for people who want them for other display projects

Quickly did this tonight As this looks so interesting I thought Ill build one myself

So heres one minor part of this Anyone else want to get involved then join us

Drill plots gerber files pcb layout for the matrix bourd below With the price of superbrights from china this now cheaper than purchasing a matrix board thats if you fancy a bit of fun

I included one design for single sided pcb one for double sided pcb

And if you have a chat with these people who knows they might even help you with making the pcbs for you

http://www.bittele.com/

Interesting, but I have already started building the 8 by 8 matrics and the circuit.
can you pls. provide me with the improve circuit with additional memory?

do you think the Eugene codes can produce english output on the display ?

This can any characters are displayed, it is only necessary to redraw the character sprites. I cited the example of a single character to do this, but if you want, I can redo all the sprites for Latin characters.

Have you got some type of flow chart for this by any chance Eugene?

It just makes life easier for understanding the asm instead of trying to work it back into ordinary english or possibly the c file that you may have originally written this in

Also looking at the shift registers I see you clock the data through via the 74HCT595 which has two register a register for placing the data into termed sh_cp the bits of which are copied into a storage register termed st_cp

You then move the conntents to the output port q0 to q7 with carry on ' q7 into ds of the next shift register

My understanding of this is, you send out a series of bytes mutliplied by number of 7HC595 then latch each storage register on the counts of 28, each column being latched on the above count selected via the 3 to 8 line decoder

Would I also be correct in saying that the visual front end would send out an entire line of information based on each sprite origination at line zero ending at line 7 Thus each line comprises 8 bits by 5 columns multiplied by number of 74Hc595

To achieve scolling right to left you right shift each line by one place as you move right

Im wondering wether I would be correct in my understanding that you would have to insert padding into each line to achieve this as well

I note that there is no inclusion of a max232 for level shifting to ttl and that equally there is no rx return path so I cant quite understand how you would confirm hanshaking protocol via the current schematic or was this not intended to be so or possibly this is not intended for pc serial interface but alternatiey there is an intermediate reciever that accomplishes ttl transition btw pc,laptop and final display hardware as depicted in your schematic

Finally whilst examining the schematic could you advise as to what IB and IE as I see no inclusion of base current limiting resistor on Q1 to Q5

Could you confirm this for me also perhaps you could advise as to what langauge the front end was written in

And wether the font end is the controlling influence with the 16F628A being the slave reciever or sub command in charges of distribution of data to the display In other words must the current application be permanently connected to the hardware for this to operate

Thanking you for info thus far

Mark

Ok Eugene, kindly assist me with the complete program in C, asm as well as the hex files pls.
I have completed the circuit and im now on the LED array using 10mm type.

Pls. I will be expecting your reply.
I go through the web page you gave me and I used Russian to English translator. Is really fun, I understand all the conversations and chart on the site.
Are u Russian?

Хорошо Юджин, любезно помогите мне с полной программой в C, asm так же как файлах ведьмы пожалуйста.
Я закончил кругооборот и im теперь на ВЕДОМОМ использовании множества 10mm тип.

Пожалуйста. Я буду ожидать ваш ответ.
Я прохожу веб-страницу, которую Вы дали мне, и я использовал русский язык английскому переводчику. Является действительно развлечением, я понимаю все беседы и диаграмму на месте.
U русский язык?

Hi mussa dont plug the hardware into your pc as yet Read my comments becuase the current schematic has no rs232 convertor for interfacing with the pic micro which means you going to be feeding the micro with plus and minus 10 volt levels and your pic micro wont like that one little bit Mr Manering

The physical specification for rs232 signals defines a logic 1 as being a voltage from -3volts to - 25volts and a logic zero as being plus 3volts to plus 25 volts

A short circuit current should never exceed 500ma
An open circuit voltage should never exceed 25 volts with ref to ground otherwise damage to port will result

In your case both the hardware your interfacing and the laptop,pc

I never rush into anything unless ive thouroughly checked it through Now you know why! ! And I dont rush for anyone else either

Hence why companies in the Uk fail every year and we have so many problems with unemployment cant do anything about the imports havent got any decent engineers and there are so many customer complaints and it winds up in a massive row every few years because they never listen Always they know better hmmm still not to worry Im sure they can explain this too

See www.beyondlogic.org/serial/serial1.htm#41 Rs232level convertors

This could also cause the pic micro' port to fail and in turn may even damage the pc port in other words your pc mother board

So ive just Eugene to come back with answers regarding this

This question mussa is for you

What is the maximum baudrate that pic processor can deal with and what should the settings be fir rs232 communication assuming you could do this which at the moment you cant acc the schematic? Discuss in full, " No im not being funny or rude, Im asking you because you are telling me youve done design work before! " , so with all due respect you shouldnt have any difficulties with that question and niether should Eugene


Mark

No, I'm Ukrainian.
But I'm an old generation (born in the USSR), so that the Russian language easily understood.

I'll rework the source for Latin characters make ready file. Wait 1-2 days.

b.t.w. my collection of binary fonts is overhere:
http://chomikuj.pl/ELisovy/FONTS/BIN

Still no answer with reference to schematic and source code and also no answers in relation to c file and still no answer reference to flow charts illustrating methods or how Eugene went about this and now of course we have export of design, import of goods into the uk and elsewhere in the world and finally we wind up with damaged laptops and also screaming angry customers bussinesses closing, refusing to accept responisibilty as usual

Then we wind up with riots, causing more damage to the industry simply because of one arrogant designer who refuses to answer very simple straight forward questions causing diplomatic relations between countries to cease to exist

I think we have the answers in black and white in the publics eye right in front of you

Right or wrong this is the attitude And a government who also refuses to listen

You want to import from them up to you my advice get it checked, send it off to an indepedant party who wont pull the wool over your eyes and who will provide you with full and thourough reports and also what to expect Information you should have from these exporters importers doesent matter which country or who they are what they are or anything else Plus of course import export fees extra taxes that you might have to pay especially back up service parts cosmetics you name it I wouldnt even attempt to do what some companies are doing or about to unless i had all the facts to hand plus questions answered in full after all this is a typical example that causes a massive deep recession with loss of homes the lot

Thats my advice if in doubt ask finally build the it yourself

Good design hmm maybe maybe not see datasheet below then