Netduino Tutorial, Knob and Sweep

In this video I show how to connect a servo to a Netduino and also how to program the servo library into a new solution. The sweep program will drive the arm of the servo back and forth while the Knob program will move the arm of the servo when you turn a potentiometer.

Here is both solutions and a text file with the program that you can copy into a new solution.

NetduinoServerTutorialFiles

 

 

If you don’t want to download the Zip file here is the code in three parts. First the Servo library class, then the sweep and knob programs.

I didn’t create the servo library class, an outstanding guy named Chris made it and I snagged it up off of the Netduino forum.

/*
 * Servo NETMF Driver
 *      Coded by Chris Seto August 2010
 *      <chris@chrisseto.com>
 *
 * Use this code for whatveer you want. Modify it, redistribute it, I don’t care.
 * I do ask that you please keep this header intact, however.
 * If you modfy the driver, please include your contribution below:
 *
 * Chris Seto: Inital release (1.0)
 * Chris Seto: Netduino port (1.0 -> Netduino branch)
 * Chris Seto: bool pin state fix (1.1 -> Netduino branch)
 *
 * This code should be pasted into a new class.
 *
 * */
 
using System;
 using Microsoft.SPOT.Hardware;
 using SecretLabs.NETMF.Hardware;
 
namespace Servo_API
 {
 public class Servo : IDisposable
 {
 /// <summary>
 /// PWM handle
 /// </summary>
 private PWM servo;
 
/// <summary>
 /// Timings range
 /// </summary>
 private int[] range = new int[2];
 
/// <summary>
 /// Set servo inversion
 /// </summary>
 public bool inverted = false;
 
/// <summary>
 /// Create the PWM pin, set it low and configure timings
 /// </summary>
 /// <param name=”pin”></param>
 public Servo(Cpu.Pin pin)
 {
 // Init the PWM pin
 servo = new PWM((Cpu.Pin)pin);
 
servo.SetDutyCycle(0);
 
// Typical settings
 range[0] = 1000;
 range[1] = 2000;
 }
 
public void Dispose()
 {
 disengage();
 servo.Dispose();
 }
 
/// <summary>
 /// Allow the user to set cutom timings
 /// </summary>
 /// <param name=”fullLeft”></param>
 /// <param name=”fullRight”></param>
 public void setRange(int fullLeft, int fullRight)
 {
 range[1] = fullLeft;
 range[0] = fullRight;
 }
 
/// <summary>
 /// Disengage the servo.
 /// The servo motor will stop trying to maintain an angle
 /// </summary>
 public void disengage()
 {
 // See what the Netduino team say about this…
 servo.SetDutyCycle(0);
 }
 
/// <summary>
 /// Set the servo degree
 /// </summary>
 public double Degree
 {
 set
 {
 /// Range checks
 if (value > 180)
 value = 180;
 
if (value < 0)
 value = 0;
 
// Are we inverted?
 if (inverted)
 value = 180 – value;
 
// Set the pulse
 servo.SetPulse(20000, (uint)map((long)value, 0, 180, range[0], range[1]));
 }
 }
 
/// <summary>
 /// Used internally to map a value of one scale to another
 /// </summary>
 /// <param name=”x”></param>
 /// <param name=”in_min”></param>
 /// <param name=”in_max”></param>
 /// <param name=”out_min”></param>
 /// <param name=”out_max”></param>
 /// <returns></returns>
 private long map(long x, long in_min, long in_max, long out_min, long out_max)
 {
 return (x – in_min) * (out_max – out_min) / (in_max – in_min) + out_min;
 }
 }
 }