computer Christmas lights

F

For The Popcorn

Well-Known Member

Most Helpful Member

• Oct 24, 2022

• #141

MrDEB said:

4 leds at one time (one of each color)

Click to expand...

Not quite. You can turn on 1 – 4 LEDs IN A GIVEN ROW.

You can't turn on LEDs in different rows, say the upper left red and lower right green at the same time for example. What will happen if you try? Unless you are actually multiplexing at > 30 and turn on ONE LED at a time. Then more than one can appear to be on at a time, with reduced brightness.

 

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MrDEB

Well-Known Member

• Oct 24, 2022

• #142

My proposed plan is to turn on row 1 then row 1 off turn on row 2=on then off row 3 = on then off row 4 on then off
repeat

 

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F

For The Popcorn

Well-Known Member

Most Helpful Member

• Oct 24, 2022

• #143

If your plan is turn on one row at a time, why are you supplying V+ from port pins?

Good luck. You're going to need it.

 

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MrDEB

Well-Known Member

• Oct 24, 2022

• #144

The Anodes of the LEDs are connected to port pins C.3 to C.6
Cathodes are grounded when desired row is grounded
V= from port pins? got confused thinking I have V+ connected directly to the rows?

 

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MrDEB

Well-Known Member

• Oct 25, 2022

• #145

I think I am ready to pull the trigger and order circuit boards

 

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P

Pommie

Well-Known Member

Most Helpful Member

• Oct 25, 2022

• #146

You seem to have the 12V and ground connections as nice thick tracks and your 5V connections very thin. And, is there any capacitors on your layout?

Mike.

 

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MrDEB

Well-Known Member

• Oct 25, 2022

• #147

2 caps next to the 5v regulator (top left) and one next to the pic .(pin 19 & 20) Thinking of adding another to pic (pin 20 & 8)

 

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MrDEB

Well-Known Member

• Oct 26, 2022

• #148

Made slight addition, added a heat sink on the circuit board for the 7805 voltage regulator.
Been worried about the heat generated by the 7805 going from 12 volts to 5 volts.

 

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P

Pommie

Well-Known Member

Most Helpful Member

• Oct 26, 2022

• #149

I guess your not bothered by the (very) thin trace carrying the 5V supply?

Mike.

 

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MrDEB

Well-Known Member

• Oct 26, 2022

• #150

I used the default of .203mm
can increase to .300 or ?

 

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P

Pommie

Well-Known Member

Most Helpful Member

• Oct 26, 2022

• #151

What are the trace widths that are feeding the regulator? All those traces are carrying the same current so should (you would think) be the same width. However, if you're happy with 0.2mm (about 8 thou) then carry on.

Mike.

 

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MrDEB

Well-Known Member

• Oct 26, 2022

• #152

Good point
here is revised PCB
has pad for heat sink on 7805 and all 5v and 12v nets are .700mm wide

 

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MrDEB

Well-Known Member

• Oct 27, 2022

• #153

An issue I have been thinking about, but need some advice.
I have 32 wires that connect the 16 LEDs to the circuit board.
On the right side of the board pictured I have 16 sockets, but can change to?
Looking at FFC FPC, wire to board or? only 10ma max per wire.
so many different choices.

 

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P

Pommie

Well-Known Member

Most Helpful Member

• Oct 27, 2022

• #154

MrDEB said:

only 10ma max per wire.

Click to expand...

That must be incredibly thin wire. Do you have a link?

Mike.

 

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MrDEB

Well-Known Member

• Oct 27, 2022

• #155

some really thin wires from the LEDs to the PCB. Been contemplating different ideas.
These are what I have the LEDs soldered to

100Sets Micro JST 2-Pin Pitch 1.25mm Single End 15cm Wire To Board Connector | eBay

Type: Micro JST 2Pin Wire Connector. Micro JST 2Pin Pitch 1.25mm Single End Wire To Board Connector 100. Length: 15cm. Plug Pitch:1.25mm. Quantity:100 Sets(100Pcs Wire Connector + 100Pcs PCB Socket ).

www.ebay.com

plan to only toggle 4 LEDs at a time (RED, WHITE, BLUE, GREEN)
The link shows some really thin wires, thus stripping to allow soldering. Thought about just adding a length of wire (26g) but would entail two soldered joints per wire.
Last idea is start over with the LEDs and solder the 26g wire to each smd LED.

 

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MrDEB

Well-Known Member

• Oct 27, 2022

• #156

Decided to just bite the bullet and redo the SMD LEDs glued to the white plastic.
Connecting 30g wire wrap wire to 26g wire has issues with stripping the small wires in the link I posted.
Thanks for looking at solutions, but will redo the LEDs then solder the 26g wire to the LEDs instead of the 30g wire wrap wire. Redesign the PCB to conform to changes.

 

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P

Pommie

Well-Known Member

Most Helpful Member

• Oct 27, 2022

• #157

I was wondering about the 10mA maximum per wire. Even 30g can carry 860mA according to this page.

Mike.

 

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MrDEB

Well-Known Member

• Oct 28, 2022

• #158

I used the wire wrap for the solder connections on the SMD LEDs as well as the LED/Neon strips. It's small and easy to conceal. The single LED is is connected so 10ma or less per LED.

 

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S

shokjok

Member

• Oct 31, 2022

• #159

My Christmas light switcher uses a 555 timer feeding a 4017 counter I.C. connected to 4 4N25 optos feeding heatsinked TIC125 triacs wired to open AC outlets. A 9v wallpack powers the switcher. The flash rate is programmable with a trimpot.
My unit has worked outdoors down to -35C/ -31F.

 

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MrDEB

Well-Known Member

• Nov 1, 2022

• #160

nice idea but for a better light controller, perhaps look at using a microprocessor.
I have 5 boards ordered but only need one. If you want one PM me.

 

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