Add functionality to existing project with Attiny85

My project is now done, and all works perfect! :slight_smile:

Here is som photos and a video:

Well done. :wink:

Indicator LED is looks like soooooooo big.
It's funny. :rofl:

Looks like it works like it should,that's the main thing!

Hehe, i know. It was just a big hole in the enclosure from earlier that i used. After soldering and connecting all the components and wires the only failure i did (again) was to use an resistor on the signal to the leds.

Everyone says to use resistor on the data output, but my leds just do not want it. So i soldered a bridge between the resistor legs and now it works perfect :slight_smile:

I don't have a clue what you're talking about but I'm happy for you that it works.

One more video that also shows the LEDs.

Resistor on the data pin that sends signals to the LEDs should pregent voltage spikes. But i have tried all from R22-1K ohm resistor and the leds just flickering all the time. Without resistor all works fine :slight_smile:

Ah that one, on the fata line of the ws2812 you mean. Yes, it's essentially used to prevent ringing, but it's not always necessary.

I have no resistor now, and nobody has called me yet, so no ringing here.

Made my self an PCB design in EasyEda, most for fun. I made it with 6 layers. One layer for VCC and one layer for GND. I will use one layer for routing. Uppper and middle layer is empty, just for the clean look :slight_smile:

I have added LM7805 regulators instead, and i have added capacitors and power led to the board etc.

Here is the updated schematic:

And despite this I can already tell your routing is not optimal. You're running thr majority of the current all the way across the pcb, right underneath all circuits and components that might be sensitive to EMI.

Why this needs to be 6 layers is beyond me btw; 2 layers would be more than enough.

With up to 20 amps through the PCB i feel i needed an own layer for main power, and one layer for ground. I have no space for making big traces that can take up to 20 amps.

Regards to EMI i can't see i have any components thst are sensitive to that?

If jou have time, i really want you to route this with just two layers. I know it's possible but i can't see why one method is better than the other here. ?

BTW. I have changed an error in schematic. I have removed the VCC_1 tag from the wire before the fuse.

Start by placing the power input, the switch and the led output close to each other. You're taking unnecessary length to run those 20A through. Place those connectors right side by side with the fuse close to them.

Virtually all of the rest of your circuit has IC's with high-impedance inputs, which also includes the data line of your addressable leds.

Not really, and I mostly don't really want to set up a library of components I'll never use just to show you that it can be done. But having looked at your previous photos, I can guarantee you it can be done, with great ease, and it'll work just fine in two layers.

Btw, this may be of use to you: Printed Circuit Board Trace Width Tool | Advanced Circuits

I see. Thanks for sharing :slight_smile:

This calculator tells me that the trace must be around 30mm thick with 20 amps through it.

I will try to change it the way you say and see if i can do it :slight_smile:

No, 30mm wide if it needs to be around 1cm long. And that would be quite feasible. But I think you can keep the length limited to a few mm.

I have tried now, and i can't see how i can make traces with 20-30mm thickness between the power terminals and ground.

The first design i made over eliminates this issue when i made one layer of VCC and one with GND. The only problem you mentioned is the EMI in that case. But is it not better to have the VCC and ground on separate layers regards to that than running huge traces on the same layer as the EMI components?

You'll never be able to make 20-30mm thick traces. But a width of that amount would be quite feasible. Show me what you've got so far.
In your case I'd put ground at the bottom and Vcc on top and just make big filled shapes with the connectors in them. The single signal trace for the data line to the leds can cut through either of the planes.

What is the difference between that method and the design i posted over?

Component placement and total number of layers. Your component placement is suboptimal IMO and the number of layers is...let's say, frivolous.