Richard Wunderlich / Joystick

Handles reading and scaling the analog inputs from a simple 2-axis joystick with a pushbutton. Can also attach rise and fall interrupts to the button.

Dependents:   joystickdeneme NOKIA_KOMBAT projekat

Purpose

Simple library for reading an analog joystick like those found on game console controllers. These joysticks usually also have a pushbutton.

Example

Joystick Library Example

// Joystick Library Example
//
// Reads the joystick x axis and fades green and red LEDs in response.
// The blue LED is turned on while the pushbutton is pressed.

#include "mbed.h"
#include <Joystick.h>

// target is the KL25Z
#define PIN_JOYX PTB0    // A0
#define PIN_JOYY PTB1    // A1
#define PIN_JOYA PTB2

PwmOut led_R(LED1);
PwmOut led_G(LED2);
PwmOut led_B(LED3);

Joystick j(PIN_JOYX, PIN_JOYY, PIN_JOYA);

// call on joystick button release
void jrise(void) {
    led_B = 1.0f;
}

// call on joystick button press
void jfall(void) {
    led_B = 0.0f;
}

int main () {
    // setup
    led_R = 1.0f;
    led_G = 1.0f;
    led_B = 1.0f;
    joypos p;    // joystick position
    // attach joystick button interrupts
    j.rise(&jrise);
    j.fall(&jfall);
    float fade = 0.0f;

    // loop
    while (1) {
        p = j.read();
        fade = p.x;
        if (fade > 0.0) {
            led_R = 1.0f;
            led_G = 1.0f - (float)fade;
        } else if (fade < 0.0) {
            led_R = 1.0f + (float)fade;
            led_G = 1.0f;
        } else {
            led_R = 1.0f;
            led_G = 1.0f;
        }
        wait(0.01);
    }
}

Diff: Joystick.h

Revision:
0:13d10cc6a822
diff -r 000000000000 -r 13d10cc6a822 Joystick.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Joystick.h	Wed Aug 05 20:21:34 2015 +0000
@@ -0,0 +1,112 @@
+/* mbed Joystick Library
+ * Copyright (c) 2015, rwunderl, http://mbed.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MBED_JOYSTICK_H
+#define MBED_JOYSTICK_H
+
+#include "mbed.h"
+
+/** Joystick position structure
+ *
+ * Struct to keep track of the joystick x and y positions.
+ */
+struct joypos {
+    double x;
+    double y;
+};
+
+/** Joystick class
+ *
+ * Reads a 2-axis analog joystick and keeps track of its positions.
+ *
+ * The joystick uses 2 AnalogIns and 1 DigitalIn
+ *     - X AnalogIn
+ *     - Y AnalogIn
+ *     - A DigitalIn (momentary pushbutton; Low is pressed)
+ */
+class Joystick {
+public:
+    /** Joystick interface
+     * Create the joystick object and assign pins.
+     *
+     * @param x X-axis AnalogIn.
+     * @param y Y-axis AnalogIn.
+     * @param a Pushbutton DigitalIn.
+     */ 
+    Joystick(PinName x, PinName y, PinName a);
+
+    /** Read the joystick position
+     * The position is returned as a joypos value with x and y in the range [-1.0, 1.0].
+     *
+     * @returns Position structure of the joystick.
+     */
+    joypos read();
+
+    /** Get the X position
+     * Read the joystick's horizontal position, represented as a double value in the range [-1.0, 1.0].
+     *
+     * @returns Horizontal position of the joystick.
+     */
+    double getX();
+
+    /** Get the Y position
+     * Read the joystick's vertical position, represented as a double value in the range [-1.0, 1.0].
+     *
+     * @returns Vertical position of the joystick.
+     */
+    double getY();
+
+    /** Get the raw X position
+     * Read the joystick's raw horizontal position, represented as a double value in the range [0.0, 1.0].
+     *
+     * @returns Horizontal position of the joystick.
+     */
+    double getRawX();
+
+    /** Get the raw Y position
+     * Read the joystick's raw vertical position, represented as a double value in the range [0.0, 1.0].
+     *
+     * @returns Vertical position of the joystick.
+     */
+    double getRawY();
+
+    /** Attach the rise interrupt
+     * Attach a function pointer to call when a rising edge occurs on the button input.
+     *
+     * @param fptr Pointer to a void function. Set to NULL or 0 for none.
+     */
+    void rise(void (*fptr)(void));
+
+    /** Attach the fall interrupt
+     * Attach a function pointer to call when a falling edge occurs on the button input.
+     *
+     * @param fptr Pointer to a void function. Set to NULL or 0 for none.
+     */
+    void fall(void (*fptr)(void));
+
+protected:
+    AnalogIn _x;
+    AnalogIn _y;
+    InterruptIn _a;
+};
+
+#endif /* MBED_JOYSTICK_H */