Week 8. Electronics Production

Group Assignment

Schematic Part

So, since in the Electronics Design week I made a not-so-good design, and I didn’t like it, I decided to create a new schematic and design.

Here is my new Schematic.

Here are the components I used: 1. Resistors – For each LED color, different resistors need to be used because they operate at different voltages and have different power consumption.

1. Voltage Regulator – Since the ATtiny1614 gets very hot when powered with 5V, I decided to add a voltage regulator to ensure I get 3.3V at the output to safely power the microcontroller.

2. Capacitors – They are very important components in a PCB. In my case, I placed capacitors:

   • Between input and GND and output and GND of the voltage regulator to minimize voltage spikes.
   • Between VCC and GND of the microcontroller to ensure stable power.

3. Pin Headers – To easily and quickly use the pins with jumper wires.

4. ATtiny1614 Microcontroller – The main thing I didn’t like about the design I made during Electronics Design week was that I created a board just for the sake of making a board. Since the ESP32 is already a complete board, I wanted to learn how to design a PCB specifically for a microcontroller. I also wanted to study datasheets, work with SMD components, and gain deeper knowledge in this area. That’s why I decided to create a new schematic and integrate the ATtiny microcontroller.

5. LEDs – I placed different colored LEDs on the pins:

   • On RXD, TXD – To visually monitor serial input and output, I added LEDs that blink when data is transmitted and received.
   • On PA3 – I placed one LED here to create LED blinks for testing.
   • On Voltage Regulator – I placed an LED after the 3.3V output to always know that the voltage regulator is working and that the board has power.
     
     Then, in the PCB editor, I imported my submarine vector and placed all the components there. Using the Freerouting plugin, I generated the traces.
     
     

Then, I exported the file as an SVG.



After exporting, I opened it in CorelDRAW to check the footprints and tracks.

Here are the output SVGs from which I will create the toolpaths.

• Setup 1, Isolating traces.
  
  
  
  
• Setup 1, Making holes.
  
  
  
  
• Setup 2, Isolating traces.
  
  
  
  
• Setup2, Cutting contour of PCB.
  
  
  
  

PCB Milling Part

For PCB milling, we have the Roland SRM-20 machine in our lab. It’s a very reliable and practically indestructible machine that offers very good precision.

Generating Toolpaths

For generating toolpaths, I used mods😎. It’s a very multifunctional and easy-to-use G-code generator for PCBs.

To create the toolpath, you need to right-click > Programs > Open Program, and in the G-code section, click Mill 2D PCB.

Then, I imported the SVG into MODS.

Then, I selected Isolate Traces and chose Offset number 4, which means that the trace will be cut at a distance of 4 times the diameter of the end mill.

After clicking the Calculate button, the G-code is automatically generated, and the file is downloaded.

Milling PCB

For attaching the PCB, I used double-sided tape.

Since I will be making a double-sided PCB, I fixed the previously cut board at a 90-degree angle. This will serve as a fixture so that during the second setup, I can flip the board and continue milling.

So, I attached the board and clamped it for 20 minutes.

Then, after securing the table on the machine, I installed a 1/8-inch mill and began setting the X and Y zero coordinates.

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For setting zero, I use a hex wrench. I loosen the mounting bolt, and the mill touches the PCB. After that, I tighten the bolt and set the Z zero.

Here is a short description of the VPanel interface for the SRM-20.

I used a 1/64 mill for isolating traces and a 1/32 mill for making holes and cutting the contour.

After setting up the machine, I started milling.

Here is the finished first setup.

Then I flipped the PCB and started milling the other side traces.

Here is what I got.

Soldering Components

I cleaned the PCB with very fine sandpaper, washed it well with soap, and started soldering the vias.

Then I soldered the microcontroller, voltage regulator, screw terminals, and pin headers.

And finally, I added LEDs, resistors, and capacitors.

Programming Part

For programming the ATtiny, I used the Atmel ICE programmer with the UPDI protocol.

Here is the connection pinout for programmer.

For programming, I used Arduino IDE. I downloaded the board megaTinyCore from board manager.

Then I selected the board.

After selecting the board , I selected the chip to ATtiny1614.

And then I selected programmer to Atmel-Ice.

I wrote a simple code where the loop will check the pins from 0 to 10, specifically sending signals with a 0.3-second delay.

Code:

void setup() {

    for (int pin = 0; pin <= 10; pin++) {
        pinMode(pin, OUTPUT);
    }
}

void loop() {

    for (int pin = 0; pin <= 10; pin++) {
        digitalWrite(pin, HIGH);
    }
    delay(300);

    for (int pin = 0; pin <= 10; pin++) {
        digitalWrite(pin, LOW);
    }
    delay(300)

Here is the Result:

Files of this Week

Kicad Project(SubMarine)

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Last update: March 25, 2025