Diff: FivePosSwitch.h

Revision:

0:0388385d4480

Child:

2:a415472059c3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FivePosSwitch.h	Sun Oct 04 19:04:26 2015 +0000
@@ -0,0 +1,63 @@
+/*
+    Bryce Williams 
+    10/04/2015
+    
+    Library for modified Sparkfun 5- Way Tact Switch Breakout (Part# BOB-11187)
+    
+        Breakout Board Mod: Remove the 10k pull- up resistors. This will make 
+                            the board a basic breakout for the 5-Way switch. 
+                            The Vcc pin (+) can be clipped or left unimplented
+                            (i.e. no connect). 
+ 
+        Circuit Setup:
+                                   Vcc 
+                                   | 
+            ----------------       |                                ----------
+            |  5- Way   (-)|-------|                                | mBed    |
+            |              |        40.0k                           |         |  
+            |  Tact     (R)|--------vvv--------|                    |         |  
+            |              |        15.0k      |                    |         | 
+            |  Switch   (D)|--------vvv--------|                    |         |
+            |              |        6.67k      |                    |         |  
+            |           (L)|--------vvv--------|--------------------|AnalogIn |    
+            |              |        2.5k       |        |           |         |  
+            |           (C)|--------vvv--------|        >           |         |  
+            |              |                   |        > 10k       |         |  
+            |           (U)|-------------------|        >           |         |  
+            |              |                            |           |---------
+            |           (+)|-----------X               --- 
+            ----------------                           GND
+        
+        Theory of Operation: Each switch output pin is connected to one terminal of
+                            a resistor (each of different value). The other terminal 
+                            is connected to a single analog in pin on the mBed. 
+                            The mBed analog pin is also connected to a 10k resistor
+                            running to ground. This makes a network of seperate 
+                            voltage dividers, between each switches output pin 
+                            resistor and the single 10k resistor from the mBed
+                            analog in pin to ground. Since only one position can 
+                            be active at a time only one voltage divider voltage 
+                            is read by the mBed. Thus each switch position produces
+                            a unique voltage, at the analog in pin of the mBed,
+                            when active.
+                            
+        NOTE: For proper operation resistor values should be as close as POSSIBLE
+              to those shown in the circuit setup diagram!                        
+*/
+#ifndef FIVE_POS_SWITCH
+#define FIVE_POS_SWITCH
+#include "mbed.h"
+
+enum ACTIVE_POSITION{NONE, UP, CENTER, LEFT, DOWN, RIGHT};
+
+class FivePosSwitch{
+    public:
+        FivePosSwitch(AnalogIn pin);
+        ACTIVE_POSITION getPosition();
+    private:
+        AnalogIn _pin;
+        static const float TOLERANCE = 0.075;     // Allowable tolerance in evaluating for active switch
+                                                  // (0.075 will give a 0.05 deadband between posistions)
+};
+
+#endif
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