Single character LED Sign and Clock - Electronic Circuits Projects Diagrams Free

justDIY · 29th May 2007, 06:42 PM

In case anyone is interested, I've made some progress on my single character LED sign project. Last week I received some fabricated pcb's from batchpcb (damn they do nice work), and have set out to turn my led sign into a time piece.

More details here:

http://projects.dimension-x.net/archives/105

**3v0** · 29th May 2007, 09:38 PM

The boards do look nice. It is nice to see that I am not the only thrifty body out there.

Gayan Soyza · 30th May 2007, 06:42 AM

Hi Your PCB looks nice to mee too. But I don’t have such a chance to make a board like that. All I do in VERO boards.

I got a super LED these days red colour ones which requires very limit current to operate unlike other ordinary red colour LED’s.

I’m making my own LED matrix board these days on the VERO board. I’m Very tired.
It consists of plenty LED’s as soon as I finish I will show you.

Still the column driver is a problem for me. At the moment I’m doing it with 4017.
It requires additional 10 transistors too.

I’m thinking whether to shift to ULN series or another type of driver IC to drive my columns which has the same RESET & CLOCK pins as 4017.

bananasiong · 30th May 2007, 07:46 AM

Hi,
Do you spray on the PCB? Or it is green in color original?

justDIY · 30th May 2007, 02:09 PM

Gayan,
you might want to consider using a ULN2803 in place of discrete transistors, and sacrificing the extra bits on the 4017, so you can match up 8 and 8. Also take a look at the Allegro A6841 - it is a shift register and a high power current sink rolled into one.

i tried using the 4017 in a 24 led matrix, I tied the 4017's clock line to the latch clock for of a 595 register I was using as the row driver. each time I latched new data to the row driver, the 4017 would activate the next column, resetting when it reached column 4. problem is, I didn't bring the reset line to the microcontroller (ran out of pins), so the 4017 would start up in random states, there was also no way to 'skip' a column if I needed to. I switched to using a 74HC139 2 to 4 decoder so I can choose which of the 3 columns are active. danger here is a software malfunction could result in multiple columns being active at the same time, possibly burning out the row driver.

A while back I did some pondering on a modular LED matrix based on high output superflux LEDs (800mA per column), as well as a controller board for it. the article may be of some help to you:

http://projects.dimension-x.net/archives/49

bananas,

the green is called a solder mask - I'm not sure if it is sprayed on or a dip coating. I don't know what color the pcb substrate is - most of the open areas on my design are filled with a ground pour, so you can't really see the substrate at all.

Gayan Soyza · 1st June 2007, 09:56 AM

Hi JustDIY thanks for your information.

That’s what I wondering the ULN series.
ULN 2803 is an OCTAL driver is there any DECADE driver in the ULN series (Ten Outputs)?

Because I must avoid using four IC drivers instead of three. I have 30 columns.
I must bare the column drivers from three IC’s with minimum components.

The 4017 works well for me but it requires additional 10 transistors + 10 resistors.

justDIY · 1st June 2007, 01:20 PM

no, you won't find ten, at least not in a power driver IC. Allegro or maybe it was Micrel used to make a 16 bit driver, similar to the 8bit driver.

Mike, K8LH · 2nd June 2007, 01:00 AM

Quote:

Originally Posted by Gayan Soyza

Hi JustDIY thanks for your information.

That’s what I wondering the ULN series.
ULN 2803 is an OCTAL driver is there any DECADE driver in the ULN series (Ten Outputs)?

Because I must avoid using four IC drivers instead of three. I have 30 columns.
I must bare the column drivers from three IC’s with minimum components.

The 4017 works well for me but it requires additional 10 transistors + 10 resistors.

How are you doing it now with 3 ICs? What 3 ICs? A '4017 and what other 2 ICs? What matrix configuration, 30 by what?

Mike, K8LH · 2nd June 2007, 01:02 AM

Sorry. Forgot to say;

"JustDIY -- nice job, nice board"... "Very pretty"...

justDIY · 2nd June 2007, 01:47 AM

gayan,

hows about just adding two more columns, then you have a 32 bit wide matrix - use two 16 bit drivers and you've saved a chip (from 3 to 2)

I couldn't find the micrel/allegro part, but TI has a 16 bit serial load parallel out register:

http://focus.ti.com/docs/prod/folder...sn74ls673.html
http://focus.ti.com/lit/ds/sdls195/sdls195.pdf

the parts are still listed as "active" but the datasheet is dated 1985, no free samples either

you could go with something like an i2c bus device, maxim makes lots of led driver chips with 16 or more outputs.

Hero999 · 2nd June 2007, 11:45 AM

How much were the PCBs?

Did you not consider etching your own?

justDIY · 2nd June 2007, 01:09 PM

Quote:

Originally Posted by Hero999

How much were the PCBs?

Did you not consider etching your own?

1) They were about $10 each.

2) I cover that about 1/2 way through my article.

Gayan Soyza · 4th June 2007, 06:34 AM

Quote:

Originally Posted by Mike, K8LH

How are you doing it now with 3 ICs? What 3 ICs? A '4017 and what other 2 ICs? What matrix configuration, 30 by what?

All three IC's are 4017.4017 x 3 = 30 outputs.

Matrix Size 30 x 7 I'm using 7 bits from PORTB.

Gayan Soyza · 4th June 2007, 06:36 AM

Thanks justDIY. I referred to the shift registers 8 bit and 16 bit ones but still the additional transistors is a problem.

Mike, K8LH · 4th June 2007, 12:20 PM

Quote:

Originally Posted by Gayan Soyza

All three IC's are 4017.4017 x 3 = 30 outputs.

Matrix Size 30 x 7 I'm using 7 bits from PORTB.

A 3 chip solution (no transistors) for a 30 x 7 matrix is certainly a challenge. I hope you don't rule out the Micrel MIC5821 or Allegro A6821 though.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

29th May 2007, 06:42 PM	(permalink)
justDIY	Single character LED Sign and Clock In case anyone is interested, I've made some progress on my single character LED sign project. Last week I received some fabricated pcb's from batchpcb (damn they do nice work), and have set out to turn my led sign into a time piece. More details here: http://projects.dimension-x.net/archives/105 __________________ If you don't have a planet, what good are gold bars? want to contact me directly? gmail gordonthree check out my project website: http://projects.dimension-x.net Favorite numbers: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

29th May 2007, 09:38 PM	(permalink)
3v0	The boards do look nice. It is nice to see that I am not the only thrifty body out there. __________________ search engine for electronic parts Junebug USB PIC programmer kit., USB Bit Wacker, 3v0's Homepage The 15 Minute Printed Circuit Board! (+drill time)

30th May 2007, 06:42 AM	(permalink)
Gayan Soyza	Hi Your PCB looks nice to mee too. But I don’t have such a chance to make a board like that. All I do in VERO boards. I got a super LED these days red colour ones which requires very limit current to operate unlike other ordinary red colour LED’s. I’m making my own LED matrix board these days on the VERO board. I’m Very tired. It consists of plenty LED’s as soon as I finish I will show you. Still the column driver is a problem for me. At the moment I’m doing it with 4017. It requires additional 10 transistors too. I’m thinking whether to shift to ULN series or another type of driver IC to drive my columns which has the same RESET & CLOCK pins as 4017. __________________ Gayan My Website http://gsmicro.blogspot.com/

30th May 2007, 07:46 AM	(permalink)
bananasiong	Hi, Do you spray on the PCB? Or it is green in color original? __________________ Superman returns..

30th May 2007, 02:09 PM	(permalink)
justDIY	Gayan, you might want to consider using a ULN2803 in place of discrete transistors, and sacrificing the extra bits on the 4017, so you can match up 8 and 8. Also take a look at the Allegro A6841 - it is a shift register and a high power current sink rolled into one. i tried using the 4017 in a 24 led matrix, I tied the 4017's clock line to the latch clock for of a 595 register I was using as the row driver. each time I latched new data to the row driver, the 4017 would activate the next column, resetting when it reached column 4. problem is, I didn't bring the reset line to the microcontroller (ran out of pins), so the 4017 would start up in random states, there was also no way to 'skip' a column if I needed to. I switched to using a 74HC139 2 to 4 decoder so I can choose which of the 3 columns are active. danger here is a software malfunction could result in multiple columns being active at the same time, possibly burning out the row driver. A while back I did some pondering on a modular LED matrix based on high output superflux LEDs (800mA per column), as well as a controller board for it. the article may be of some help to you: http://projects.dimension-x.net/archives/49 bananas, the green is called a solder mask - I'm not sure if it is sprayed on or a dip coating. I don't know what color the pcb substrate is - most of the open areas on my design are filled with a ground pour, so you can't really see the substrate at all. __________________ If you don't have a planet, what good are gold bars? want to contact me directly? gmail gordonthree check out my project website: http://projects.dimension-x.net Favorite numbers: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

1st June 2007, 09:56 AM	(permalink)
Gayan Soyza	Hi JustDIY thanks for your information. That’s what I wondering the ULN series. ULN 2803 is an OCTAL driver is there any DECADE driver in the ULN series (Ten Outputs)? Because I must avoid using four IC drivers instead of three. I have 30 columns. I must bare the column drivers from three IC’s with minimum components. The 4017 works well for me but it requires additional 10 transistors + 10 resistors. __________________ Gayan My Website http://gsmicro.blogspot.com/

1st June 2007, 01:20 PM	(permalink)
justDIY	no, you won't find ten, at least not in a power driver IC. Allegro or maybe it was Micrel used to make a 16 bit driver, similar to the 8bit driver. __________________ If you don't have a planet, what good are gold bars? want to contact me directly? gmail gordonthree check out my project website: http://projects.dimension-x.net Favorite numbers: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

2nd June 2007, 01:02 AM	(permalink)
Mike, K8LH	Sorry. Forgot to say; "JustDIY -- nice job, nice board"... "Very pretty"...

2nd June 2007, 01:47 AM	(permalink)
justDIY	gayan, hows about just adding two more columns, then you have a 32 bit wide matrix - use two 16 bit drivers and you've saved a chip (from 3 to 2) I couldn't find the micrel/allegro part, but TI has a 16 bit serial load parallel out register: http://focus.ti.com/docs/prod/folder...sn74ls673.html http://focus.ti.com/lit/ds/sdls195/sdls195.pdf the parts are still listed as "active" but the datasheet is dated 1985, no free samples either you could go with something like an i2c bus device, maxim makes lots of led driver chips with 16 or more outputs. __________________ If you don't have a planet, what good are gold bars? want to contact me directly? gmail gordonthree check out my project website: http://projects.dimension-x.net Favorite numbers: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

2nd June 2007, 11:45 AM	(permalink)
Hero999	How much were the PCBs? Did you not consider etching your own? __________________ I also post at the following sites: http://www.stop-microsoft.org http://www.heated-debates.com Screen name: Aloone_Jonez And http://www.silicontronics.com, same screen name as here.

4th June 2007, 06:36 AM	(permalink)
Gayan Soyza	Thanks justDIY. I referred to the shift registers 8 bit and 16 bit ones but still the additional transistors is a problem. __________________ Gayan My Website http://gsmicro.blogspot.com/