computer Christmas lights

[MrDEB]

years ago I assembled a Compurterized Christmas light display but since sold the entire setup.
I recall the SSR or triac boards used an opti-isolator, couple resistors but instead of using a computer, I want to just use a PIC to drive the opti_isolator. Just started looking for leftover plans and parts but figure would ask first.

 

[MrDEB]

here is the revised schematic with corrected connections on the PCB.
If the Mosfets draw very little current then the 7805 should not get hot. Maybe when it got hot it destroyed the 18f2221?
Plan to investigate in the morning.

 

[For The Popcorn]

Sorry, I can't tell a darned thing from your exploded parts diagram.

If you could please draw out the complete circuit of one LED, showing all connections, resistors, mosfet(s), power, ground and port pins, somebody might be able to understand what you're doing.

 

[tumbleweed]

If you need more current at 5V than the 7805 can provide, there are small DC-DC converters that have the same pinout and can drop into the pcb to replace the 7805, like https://recom-power.com/en/products.../switching-regulators-sip/rec-s-R-78-0.5.html

There are a number of different mfgs and sizes. Available at digikey and mouser.
I think we've probably mentioned them in one of your threads, maybe even this one somewhere.

 

[MrDEB]

If the Mosfet gate resistors are 1K then the GATE is limited to 5ma at 5volts so more current may not be the issue.
Contemplating that MAYBE I have a short in my wiring. Thinking about this before going to sleep last night. First looking at the 9 position male / female plugs. Could be why the red LED strips don't light up.
Not to change the subject, I have started drawing a new schematic to satisfy Jon, visitor or for the popcorn or what ever he is calling them selves these days/ Using EASYEDA.
ONE feature, if available, is highlighting the connected nets. Diptrace has this

 

[For The Popcorn]

ONE feature, if available, is highlighting the connected nets. Diptrace has this

Please show us how this helps anybody follow your deficient "schematics" you post repeatedly. YOU may be able to highlight a net on your screen, but that does ****-all good to anybody looking at a picture of it.

Don't create a new schematic on my behalf – perhaps if you draw an accurate schematic, somebody (else) will be able to help you.

And just to reiterate what tumbleweed said, the GATE current on a mosfet is effectively ZERO. Take the resistor out, and it will still be effectively ZERO.

 

[MrDEB]

here is the same basic schematic done using EASYEDA. IMO it is a rats nest trying to follow the wires.
now how to post a schematic? tried exporting as easyeda file as well as pdf

 

[MrDEB]

refering to post# 223 https://recom-power.com/en/products.../switching-regulators-sip/rec-s-R-78-0.5.html checked Mouser and digikey = none

 

[MrDEB]

looking at octapart should have done this first.

 

[MrDEB]

well here is a screen shot

 

[rjenkinsgb]

All the FET gate to source resistors should be vastly higher value, eg. 100K.

With equal resistors you are halving the gate voltage and drawing unnecessary current from the PIC outputs.

 

[tumbleweed]

The way you changed the resistors around the IRL520 you now have a voltage divider that pulls about 2.5mA. You used to have a larger pull down, which would be fine. You're lucky... at 5V it's still high enough to meet the min Vgs threshold (2.5 vs 2.0v).

Stop just randomly changing things.

 

[For The Popcorn]

Presumptions:

1. Each of the 2 pin jacks has a single LED attached to it.

2. Each column of 2 pin jacks has 4 of the same color LEDs attached.

3. Eight places where you've indicated 320 ohm resistors are in fact 330 ohm resistors.

4. The gate pull down resistors are as rjenkinsgb suggests, much greater than 1k.

If all of the above are true, the four single LEDs will draw slightly less than 10mA, and each column will also draw slightly less than 10mA no matter if 1 or all 4 LEDs are illuminated. 4 × 10 + 4 × 10 = 80mA for those LEDs, the most significant 5 volt draw from the regulator. The PIC18F2221 might draw 25mA, so that's close to 100mA total draw on the 5 volt supply.

Pd = (Vs - Vreg) × I = 7 × 0.1 amp = 0.7 watt. If you're using a 7805 in a TO-220 case, it shouldn't be getting too hot (warm, yes, burning hot, no) assuming the above points are true AND the schematic reflects reality.

Thank you for creating a readable schematic. The point wasn't to use EasyEDA – the point was to draw a readable schematic. You could have done it on a piece of paper with a pencil.

 

[For The Popcorn]

I must say, if your schematic is accurate, your groups of 4 LEDs aren't doing what you thought they would.

The attached schematic shows what you have: 4 parallel LEDs with one resistor connected between two port pins. If one of the port pins is high and the other low (can't say which is which because you don't show the LED polarity), all 4 LEDs will be on. If both port pins are high or both are low, all 4 LEDs will be off. Also, if either port pin is an input, all four LEDs will be off. All 4 LEDs of a group are on or off. You can't control the LEDs of a group independently.

You could have accomplished the same thing with a single port pin per group.


To export a schematic from EasyEDA, FILE/EXPORT/PNG. Select SIZE between 1x and 2.5x to get adequate resolution.

 

[MrDEB]

the 1K resistors are supposed to be 10K My mistake
my plan is to start by making the columns all high then cycle through the rows. Basically the rows are cycled low so only 1 led per row is on.
treat it like a 4 x 4 matrix so one led is on per row then cycle through the matrix.
I need to get everything else working then work on the sprinkles on the cake.
I think I located a mistake in connecting the male/female plugs thus causing the 7805 to get hot and destroy the pic.
I now have 2 working boards and will test today with a temp probe on the lm7805

 

[For The Popcorn]

my plan is to start by making the columns all high then cycle through the rows. Basically the rows are cycled low so only 1 led per row is on.
treat it like a 4 x 4 matrix so one led is on per row then cycle through the natrix.

That might be your plan, but if the schematic you posted is accurate, that's not going to be possible as I illustrated. You either have 4 LEDs in a column ON or 4 LEDs in column OFF. Those are the options for the circuit you have drawn.

 

[MrDEB]

Thinking of toggling the colums as well.
Here is my corrected schematic

 

[MrDEB]

I tried FILE/EXPORT/PNG. but it dosen't work

 

[For The Popcorn]

Sigh. Whatever. Works for hundreds of other EasyEDA users.

 

[For The Popcorn]

Perhaps more than a statement of "It doesn't work" would allow somebody to help you figure it out.

 

[MrDEB]

the uploaded file does not have an allowed extension. the following extensions allowed
sub, say, asc,asm, bas, bin, bmp, brd, bx2, c, doc, exe,gif, gz, h, hex, ino, jpeg