PCB schematic for 16 led 12 pattern pcb

The black piece on the front is labaled LOTB.
The pic on the back is 16f688

The PIC in the photo drives each pair of LEDs in series from a drive line. If you want high brightness you will need a PIC16F6xx The PIC 16F628 has a lot of back-up.
The same set of instructions apply to the PIC 16F628 and the PIC12F629. The PIC 16F628 has 18 pins

I think for a model car it would be bright enough. I wouldn't want the leds flashing over to other sections off the light bar.
Colin could you draw something up for me? Maybe a layout like you did before?

Why not just buy the device in the photo?

blueroomelectronics said:

Why not just buy the device in the photo?

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This is mine, I have a sample of it, but I need a layout/schematic so I could get more.
I didn't manufacture this, it is a sample.

A sample is designed so you can order more, who made the sample?

blueroomelectronics said:

A sample is designed so you can order more, who made the sample?

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One off my old friends made this for me, I have lost contact with him over the last year.

Thanks to everyone who helped me out.

You must have a very professional "friend" as I have one of those boards too.

Yes he works with pcbs, he didn't make the actual design, he worked with a manufacturer. What are you trying to say collin?

I could create schematic for you, and give you the eagle file.
so you can put it on PCB yourself.

would you be willing to pay a few $?

I'd design using 74hc595, no transistors/resistors,
and without the PIC, and including a short explanation of the serial interface.

I have a working prototype with SMD LEDs, normal 20mA type, and one 4-digit LED display, so design time won't be very long.

you could edit/expand it youself for more LEDs.

It can work with almost any PIC:

one data line
one data clock
one storage clock

if you have slow PIC frequency, you could use more data lines parallel.

if you do not have EAGLE, you'd just get a schematic, of which the principle of operation is tested and verified.

I can also help if you need SMD ICs, or PICs.

this is not charlieplex method, where only one LED can be active.
but never tested for more than 5 volts, i.e. 6 volts.

nike6 said:

I'd design using 74hc595, no transistors/resistors,
and without the PIC, and including a short explanation of the serial interface.

Click to expand...

Why use glue logic when none is necessary?

because I get the IC's at a price of 15 cents/each on a small reel.

there are many reasons.

one is, you design a display PCB, and just plug it into various prototypes, as needed.
there is only one standard serial protocol, no charlieplex.

you could even use a 12f509 or 16f54, just for a flashlight.

in my belief, using these IC's via bulk supply is the best, cheapest way of driving small displays and matrix.

the software interface is straightforward, and the physical plug can be made as small as 5-pin, even the carrier PCB can recognize different displays just using a few extra pins.

then the prototype testing is finished, and?
do you bury LEDs, and displays on the PCB?
you can just remove the display PCB, and use it for a new prototype.

you could ask in a similar way, why do you try to save $2, and use a 8x2 LCD,
when these $2 are absolutely not essential?
**broken link removed**

sure this is not the only way to cut costs, also new OLED's are considerably low price, and have pixel-graphics.

yet for the numerous flashlight variations as required, I'd even suggest a 18F PIC, so it is not required to wrestle with program memory space.
but not a 12f509, which could be used just for one or two patterns.

one person may do it this way, another person that way.

A skilled programmer could do an 8 LED, 1 switch design with an 8pin PIC saving the modes in internal EEPROM. Cheaper than any glue logic design.
The posted design uses an inexpensive 16F88 (the slightly cheaper 16F628A should work just as well) Saving a buck or two is of little importance in a low quantity design (we're not sure if the OP wants them for personal use or to sell them)

yes you're right.

I just use different models.

16f57 as the low-key solution (not 16f54 anymore).
16f716 for 8bit A/D
16f884 for RS232, more memory
18F13k50 for USB, 8k ,1k RAM

if you order 25 of each of these PICs, you'll get some difference in the end, and you may consider if a 16f884 is always required.

I just do not get the advantage of charlieplex. If i just want 8 or 10 LEDs, I'd wire 16f54 directly, it can drive all the LEDs directly. I made a few such flashlights, one powered via 1.2V AA cell.

you are right for 16 LEDs, no mutiplex would be required, if you use a 16f57.
but can you light them up all at once?
you'd have to use low-current LEDs.

for larger number of LEDs, you'd have to use driver IC anyway, if you want some level of brightness.
and for a 7-seg LED, you can not use charlieplex anyway.

so why have an extra charlieplex code set, when you just can add one more serial buffer, and drive extra LEDs as needed?

it's maybe just personal preference.
but no company would offer charlieplexed LED matrix modules, i guess.

some people wonder about these TIL311 modules, why they never found broad application, and why the price is so high.
maybe they just want to keep people's brain in motion?

Charlieplexing is a handy way to drive LEDs with the fewest pins / parts possible. Works well enough if you use bright LEDs.

so why have an extra charlieplex code set

Click to expand...

in the long run it's less expensive than hardware.

A PIC can easily drive an LED at 20ma modern LEDs are really bright compared to the ones made a decade ago.

IMO glue logic (gates, flipflops, counters) only adds complexity in some circuits, high current driver ICs or interface ICs don't count as they are beyond what the MCU can do.


Companies do offer charliplexed ICs, check out Maxim semiconductor.
The TIL311 is about 30yrs old, expensive and power hungry (they run quite hot), I guess the popularity of the common LCD display killed of sales of the TIL311 after all just four of them could set you back nearly $100. I sold off about a dozen on eBay last year.

for larger number of LEDs, you'd have to use driver IC anyway, if you want some level of brightness.
and for a 7-seg LED, you can not use charlieplex anyway.

Click to expand...

A driver IC is not glue logic, and you actually can charliepex 7 segment displays but a typical mux is more common.

For something as simple as the OPs 8 LED 1 button circuit glue logic is unnessary.

my local vendor, which is originally based in UK, has the TIL311 listed, guess 11 euro's or something, that's 15 dollars.
expensive, would say, luxury.
don't know if they just have them on stock, or if they are still used in specialized fields.

early monsanto displays from 1970s also are based on such a "fake" dot matrix.

charlieplexed LED displays are not so good when the original datasheet is not available.
it is a complicated scheme, I've read the original MAXIM documentation, exploiting drive and sinking electrical effects, and potentials.

I've built a 5x7 dotmatrix PCB, and just tested the dots using a multimeter (the datasheet also available somewhere).

Also I'd say recently i rather tend to work with LED matrix, which i have usually experienced driven using row/column multiplex.

I mean, you get this foreign LED display, no schematics available, and can not just simply drive a serial pattern.
in most cases, you'd have to re-design.

modern matrix displays usually employ a specialized driver IC, such as the one's made by sure electronics.

incidentially, in our country, we have 3 metre high LED sign boards, made from 5mm LEDs, and 100s of standard DIL 74hc595.

you can easily guess the way how they are wired, even if you do not have schematics available.

yet if low-current LEDs are used, which have considerable brightness at 5 or 8 mA, even a complete matrix can be driven directly by PIC.
even the LCX244 used to sink the rows, stricly speaking, would not be required.
yet it can also disconnect the rows from the bus.

nike6 said:

incidentially, in our country, we have 3 metre high LED sign boards, made from 5mm LEDs, and 100s of standard DIL 74hc595.

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That's what made me remember you, you're not in Ireland your in Japan or somewhere in the Pacific. I recall that from your bizarre posts over at the Microchip forums hybridpic / nikemoto2511.

I take it you never did figure out charliplexing.

Hmm I made a new web page, which is:

1. not really bizarre, there is .ASP plug board, which is linked via IFRAME and powered by Windows Server 2003. web domain hosted by Bangalore service provider. the page itself indeed is based indeed on geocities Japan.

2. I have not introduced this gateway page on the MC forum.

3. I could make a video of this sign board, indeed i have in in mind for months.

4. I have read the MAXIM document about the charlieplex. it is just not relevant to my requirements.

5. I have new hi-tech BBS, where unless wikipedia, there is no policy against advertising.

any other questions?

i think the MC forum will change in the near future, they will hire some pro's, and drop the amateur volunteer advice.
then like Freescale forum, it will become a pure support BBS, not for projects introduction, neither for personal adverts, or bizarre illustrations.

I mean, if I'd be them, i'd hire 3 to 5 pro's, to handle support questions, instead of having volunteers who sometimes maintain personal communications.

the best replies i got over there have been from MC staff participating, when I asked about MPLAB, and device programmers.

6. I also link to their IC wiki (Microchip), from my web page, but participation is rather low-key, maybe once a month.
but not to the forum they also do not have an appreciate button to do this.

hope the thread creator does not report me for being off-topic.

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