Need a LED switch

I saw only the photo of the board, no schematic, maybe because of limitations in my newsreader. This is another reason why not to post binaries in text usegroups. Other usenet providers might filter binary messages completly. If you don't have your own webspace, you could use something like this:

and then post the link to the images. Of course, the schematic is obvious and thanks, but I don't want to buy one :-)

Maybe John wants to do this, I'm not an expert in 1970's technology :-) My favorite technology at the moment are CPLDs and FPGAs:

This could be done with a $2 CPLD, but a < $1 PIC is better for this task. If 8 outputs and inputs are sufficient, a slightly modified version of my PIC monoflop project would do it:

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Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de

Nice, I happen to be useing a PIC18 for another project.

So I used that, it had 28 pins in a DIP package.

Re-using code also helps.

don

PS: the schematic was a pdf file. I have not seen it show up here so I guess your right, the newsreader ate it.

I reposted the pic and pdf to alt.binaries.schematics.electronic by the same subject name.

What compiler do you use? For a commercial project with a PIC18F252 I bought the C18 some time ago and it works nice. I think you can get this even for free, for non-commercial projects.

Today I've started to test the PIC18F2550. This is the report (and a bit of a tutorial) for my "Hello World" program with timers, interrupts, capture/compare module and serial port interface, in assembler:

It is a nice inexpensive and powerful microcontroller with an integrated USB interface.

--
Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de

Hi Frank,

I am using a full version of C18 compiler from Microchip and an ICD2.

Whenever a new client wants to use a chip I am unfamiliar with, I get the client to buy the new compiler for me^H^H the project.

I try to do as little as possible in assembly. The cost difference from two versions of the same chip with more code space is so small, I don't bother to wrap my head around assembly any more.

Getting a project/product built onto an Olimex board is a good start as a proof of concept before a board layout is committed to.

I have been looking into the PIC USB parts, but I have not got anything working yet.

don

Yes, I'm trying this, too. But nowadays many high quality compilers are free, e.g. for the PIC16 series, or GNU GCC for STM32 and other ARM CPUs.

And at least the C18 compiler is really good in hiding the weird PIC architecture with banking, Harvard architecture etc. :-)

For more complicated parts in QFN or other small packages, Olimex boards are fine. For PICs most (all?) parts are available as DIP and nearly no external parts are needed, so why not using a breadboard for the proof of concept?

--
Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de

Very true, makes prototyping and expermenting easy.

I have not had very good luck with these plug boards.

More often then not, I give the prototype to the client.

They like to see the first pass on their product.

I do enjoy building these prototypes with the final parts.

This helps in seeing how those parts will fit onto a PCB.

don

Yes - less than a few hours using hardware. I posted the schematic (on 8/15) that modifies a standard 10 LED chaser that Rich and the OP discussed. After realizing that the first one I posted required the operator to release the foot switch quickly, I wanted to be sure the better design worked properly, so I breadboarded it. I think it took me less than an hour to build, but I wasn't timing myself.

A PIC solution is nice, too. Certainly a lower parts count and cheaper switches (dip vs toggle) than the hw solution I posted. Good picture - I like the Olimex development board you used. Of course, the solution is incomplete without the source code, but maybe it is as easy to Google that as it is to Google debounce circuits.

Ed

Yes, 1950s technology right ?? Relays !!!

When I saw the relays, I thought you were joking, so I did not take your post seriously.

All 10 LEDs with 10 relays !!??

You are better with a soldering iron then I am, for sure.

Thanks

don

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I just found your post.

Please don\'t post binaries to text-only groups since most (all?) USENET
servers wont propagate them.


Nice job, but in answer to your question, no.

Not like that at all; what I had in mind was a pure hardware solution
which the OP could wire up himself without having to learn how to
program and buy/build the equipment needed for what is most likely a
one-off device.

  
JF

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If you\'re finding fault with that position, then I suggest PKB.

--
Here\'s some \'60\'s technology that _always_ works. ;)

news:bot9a596ubhf2qa1k5ju9c7oh7nq8926m0@4ax.com

JF

This is true.

I checked over the past posts to get more information about the req's.

One thing I have guessed at:

If all but one LED is bypasses. At each foot switch input, should: the one remaining LED stay lite or the one remaining LED toggle on-off.

I also did not find if the any LEDs should be lite at powerup. So I left them all OFF at power up.

ROFL, I am from your age group, I have been doing this for a long time. I still have my wirewrap tools in a box under my workbench.

I taught digital electronics in the USAF at Lowry AFB in Colorado in the

70s. My degree is in Computer Science, I had my heart on BIG IRON of the 70S, the IBM 360.

But, I discovered the Z80 and HC11 in the early 80s and never looked back.

I have not done TTL design in over 20 years.

[Now that I think about it, I did do an ECL design on the Testmaster 6000 for a memory board company in the middle 80s. The operating system was CPM/80. I enjoyed the software more then the ECL design. ]

A few little circuits here and there, some CPLDs or small FPGA, but all microcontrollers now.

I have both feet firmly planted in the 90s. ;-)

don

John Fields wrote: < after looking at your PICs on a.b.s.e. >

Where are the LEDs ??

don

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That\'s not the LED switch circuit, it\'s just an example of using
perfboard for prototypes. :-)

JF

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Sorry \'bout that... :-)

Sure looks like I called that one wrong.  

JF

No problemo !

I see so many "newbe"s here that sometimes I wonder where some of the "engineers" come from.

I do like you VHDL site tho.

don

I don't know when they were invented or came into general use, so they could be earlier than '50s technology.

If you saw relayS (plural) you did not understand the schematic, or the post.

You did not understand the schematic or the post. There is only one relay.

Ed

I found that post. You are correct, there was only one relay.

Very creative, If a customer saw a relay in a new design, would they buy it ??

don

I suppose that depends on the customer, design and application. Mouser lists over 18,000 relays in their catalog, Digikey over

12,000 (plus another >4K SSR's) and Newark close to 8,000, so there is considerable demand for them.

Do you think older (i.e. pre 90's) technology is bad because it's old? Seems like you do. Or is it just that PIC's are so good that anything else is bad, in your view?

Focussing just on a PIC solution, could you use an older, smaller PIC (maybe an old 16F84) to do the job?

Off the top of my head, something like set ports to input at start, read the dip switches, load the bypass registers (10 bits), set ports to outputs (except A4, used for interrupt) then enter the counting loop. Test the bit in the bypass registers that matches the count, and do an extra advance when the bit is set.

Ed