Find the PCB files here

📄 PCB linear actuator and servo motor control

This circuit should control linear actuator, servo motor, and 2 capacitance sensors.

The mill tools I used were in okay shape which resulting in an okay board. I needed to do a lot of scraping to clean my board.

I soldered a xiao rp2040, a driver, pins for capacitance sensing, a linear actuator, and a servo motor.

Parameters:

  • wire thickness: 16 mil
  • clearance: 16 mil
  • board perim clearane: 40 mil mil = 0.1 inch

Components:

See video of linear actuator testing here. The motor movement is a little slow because I didnt have the correct power supply with me (I had a 12V wall wart instead of a 24 V if I remember correctly). I didn’t video the servo motor, but the servo worked well.

arduino script: servo example

#include <Servo.h>

Servo myservo;  // create servo object to control a servo
// twelve servo objects can be created on most boards

int pos = 0;    // variable to store the servo position

void setup() {
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
}

void loop() {
  for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
    // in steps of 1 degree
    myservo.write(pos);              // tell servo to go to position in variable 'pos'
    delay(15);                       // waits 15ms for the servo to reach the position
  }
  for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
    myservo.write(pos);              // tell servo to go to position in variable 'pos'
    delay(15);                       // waits 15ms for the servo to reach the position
  }
}

Tips:

  • drc = design rule check
  • scrape parallel to lines , you dont need to be too gentle if your traces follow drc
  • for macOS users the xiao instructions are slightly different. Arduino>Settings>Additional board manager URLs> “https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json"
  • don’t forget to tape the bottom of the microprocessor if you chose the taped component from library … this might be why servo code isn’t working
    • update here is that you need to check xiao rp2040 pinout and call the P pin number rather than the digital pin number printed on the board

Instructions for milling:

  • upload brd file to OtherMill
  • use double sided tape to place one sided-copper piece down.
  • set up the job by placing your design ~5 mm away from each edge (use the right panel to move)
  • press start, machine will prompt you for the type of nmil you need, ask you to place it, and test the distance to board AFTER you press start.
  • we were using 1/36 " end mill and 1/16” if I remember correctly?

Alt board design: I made a cookie pcb where each LED is a sprinkle! I want to mill this and use as soldering practice.