BakeBit - JoyStick/zh

English

1 介绍

JoyStick

• BakeBit - JoyStick是一个摇杆模块，可以反馈二维平面的X和Y方向的运动。

当拨动摇杆时，接入电路的滑动变阻器的阻值就发生变化，对应的X/Y电压值也随之变化。

2 特性

• 使用标准的2.0mm 4 Pin BakeBit接口
• 模拟信号输出
• PCB尺寸（mm）：24*42

• 引脚说明:

名称	描述
GND	地
5V	电源5V
X	X方向信号输出
Y	Y方向信号输出

3 示例程序：UI Control via Joystick

这个项目实现一个简单的设置界面，并使用摇杆来操控界面上的元素，一个很实用的例子，在程序运行时，摇杆的上下是移动要操作的项目，左右用于更改设置。
本示例需要配合BakeBit - OLED 128x64使用。

3.1 硬件连接

简单的将 摇杆 插入 A0接口，将 OLED 插入 I2C 接口，如下面这样：

3.2 示例源代码

import bakebit_128_64_oled as oled
import bakebit
import time
 
 
oled.init()                  #initialze SEEED OLED display
oled.clearDisplay()          #clear the screen and set start position to top left corner
oled.setNormalDisplay()      #Set display to normal mode (i.e non-inverse mode)
oled.setPageMode()           #Set addressing mode to Page Mode
 
# Uses two pins - one for the X axis and one for the Y axis
# This configuration means you are using port A0
xPin = 0
yPin = 1
bakebit.pinMode(xPin,"INPUT")
bakebit.pinMode(yPin,"INPUT")
 
texts = ["Wi-Fi"
    , "Bluetooth"
    , "Media Vol"
    , "Alarm Vol"
    , "FontSize"
    , "Brightness"
    , "Dim" ]
 
values = [True
    , False
    , 50
    , 50
    , 9
    , 80
    , 30 ]
 
opIndex = 0
m = int(1024.0/5)
while True:
    try:
        # Get X/Y coordinates
        x = bakebit.analogRead(xPin)
        y = bakebit.analogRead(yPin)
 
        oled.setTextXY(0,0)
        oled.putString("[Settings]")
 
        if x<m:
            # left
            print("left")
            if type(values[opIndex]) is int:
                values[opIndex]=values[opIndex]-1
                if values[opIndex]<0:
                    values[opIndex] = 0
            elif type(values[opIndex]) is bool:
                values[opIndex] = not values[opIndex]
 
        elif x>(1024-m):
            # right
            print("right")
            if type(values[opIndex]) is int:
                values[opIndex]=values[opIndex]+1
                if values[opIndex]>999:
                    values[opIndex] = 999
            elif type(values[opIndex]) is bool:
                values[opIndex] = not values[opIndex]
        elif y<m:
			opIndex = opIndex - 1
        elif y>(1024-m):
			opIndex = opIndex + 1
        elif opIndex<0:
			opIndex=6
        elif opIndex>6:
			opIndex=0
 
        for i in range(7):
            oled.setTextXY(0,i+1)
            valueStr = ""
            if type(values[i]) is int:
                valueStr = str(values[i])
            elif type(values[i]) is bool:
                if values[i]:
                    valueStr = "On"
                else:
                    valueStr = "Off"
            for j in range(3-len(valueStr)):
                valueStr = " " + valueStr
 
            title = texts[i]
            if len(title) > 10:
                title = title[:10]
 
            for j in range(10-len(title)):
                title = title + " "
 
            if opIndex == i:
                oled.putString("> " + title + " " + valueStr)
            else:
                oled.putString("  " + title + " " + valueStr)
    	print("x =", x, " y =", y, " opIndex=", opIndex)	
 
    except IOError:
        print ("Error")

Github

3.3 运行示例

假设你已经参考bakebit教程安装了BakeBit源代码，
要运行示例程序，可以在开发板上进入 BakeBit/Software/Python目录,运行bakebit_prj_UIControl_via_Joystick.py:

cd ~/BakeBit/Software/Python
sudo python bakebit_prj_UIControl_via_Joystick.py

3.4 运行结果

程序运行时会在OLED上显示一个设置界面，上下拨动摇杆移动项目前面的光标，左右拨动更改设置，如下图所示：

4 相关资料

• [Schematic](BakeBit - JoyStick.pdf)
• [BakeBit Github项目](https://github.com/friendlyarm/BakeBit)
• [BakeBit Starter Kit手册](http://wiki.friendlyarm.com/bakebit/bakebit_starter_kit_manual_cn.pdf)