*Always use a resistor! Dont imitate my bad habit!
force sensor schem.PNG 103.22KB
179 downloads
force sensor schem 2.PNG 41.62KB
188 downloads
force sensor test.jpg 790.22KB
138 downloadsMagic! Oh right the code....
AnalogInput input = new AnalogInput(Pins.GPIO_PIN_A0);
PWM led = new PWM(Pins.GPIO_PIN_D10);
input.SetRange(0, 100);
while (true)
{
led.SetDutyCycle((uint)input.Read());
Thread.Sleep(1);
}
To enable event firing use this class I created [since analog port doesnt have built in event stuff]
using System;
using Microsoft.SPOT;
using SecretLabs.NETMF.Hardware;
using Microsoft.SPOT.Hardware;
using System.Threading;
namespace Sensors
{
public delegate void ChangedValue(int oldValue, int newValue, DateTime time);
public class Force
{
public event ChangedValue ValueChanged;
Thread updater;
AnalogInput input;
int oldVal = -1;
public int ignoreChangeLessThan = 0;
public Force(Cpu.Pin analogPin)
{
input = new AnalogInput(analogPin);
}
public void SetRange(int min, int max)
{
input.SetRange(min, max);
}
public int Read()
{
return input.Read();
}
public void UpdateConstantly(bool update)
{
if (update)
{
updater = new Thread(new ThreadStart(Update));
oldVal = input.Read();
updater.Start();
}
else
{
if (updater != null)
updater.Suspend();
}
}
private void Update()
{
while (updater.IsAlive) // as long as we havent stoped the thread...
{
int newVal = input.Read(); // get the current value
if ((newVal < oldVal - ignoreChangeLessThan) || (newVal > oldVal + ignoreChangeLessThan))
{
if(ValueChanged != null)
ValueChanged(oldVal, newVal, DateTime.Now); // if the value has changed more than the filter value then fire the event
oldVal = newVal; // now this is the new value to base a change off of.
}
}
}
}
}
Use:
static Force f = new Force(Pins.GPIO_PIN_A0);
public static void Main()
{
f.ValueChanged += new ChangedValue(f_ValueChanged);
f.UpdateConstantly(true);
Thread.Sleep(Timeout.Infinite); // just keep on waiting... forever
}
static void f_ValueChanged(int oldValue, int newValue, DateTime time)
{
Debug.Print("Old: " + oldValue + " || New: " + newValue);
//f.UpdateConstantly(false); // stop the updating using that line
}
When ignoreChangeLessThan is 0 you'll get tons of fires, i suggest a setting of 3 depending on your range or sensor you'll have to fiddle with values.
Sample output (tiny part of it) with ignoreChangeLessThan being 0:
Old: 810 || New: 823
Old: 823 || New: 836
Old: 836 || New: 847
Old: 847 || New: 855
Old: 855 || New: 865
Old: 865 || New: 873
Old: 873 || New: 878
Old: 878 || New: 886
Old: 886 || New: 892
Old: 892 || New: 899
Old: 899 || New: 903
Old: 903 || New: 907
Old: 907 || New: 911
enjoy
Attached Files
-
Force Sensor.zip 50.33KB
15 downloads
