Bryce Williams / FivePosSwitch

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Fork of FivePosSwitch by Bryce Williams

FivePosSwitch.h@3:dcb9eef119cf, 2015-10-04 (annotated)

Committer:
electromotivated
Date:
Sun Oct 04 19:50:26 2015 +0000
Revision:
3:dcb9eef119cf
Parent:
2:a415472059c3
Child:
4:10c4b7cb4e8c
v1 release;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
electromotivated 0:0388385d4480 1 /*
electromotivated 0:0388385d4480 2 Bryce Williams
electromotivated 0:0388385d4480 3 10/04/2015
electromotivated 0:0388385d4480 4
electromotivated 0:0388385d4480 5 Library for modified Sparkfun 5- Way Tact Switch Breakout (Part# BOB-11187)
electromotivated 0:0388385d4480 6
electromotivated 0:0388385d4480 7 Breakout Board Mod: Remove the 10k pull- up resistors. This will make
electromotivated 0:0388385d4480 8 the board a basic breakout for the 5-Way switch.
electromotivated 0:0388385d4480 9 The Vcc pin (+) can be clipped or left unimplented
electromotivated 0:0388385d4480 10 (i.e. no connect).
electromotivated 0:0388385d4480 11
electromotivated 0:0388385d4480 12 Circuit Setup:
electromotivated 0:0388385d4480 13 Vcc
electromotivated 0:0388385d4480 14 |
electromotivated 0:0388385d4480 15 ---------------- | ----------
electromotivated 0:0388385d4480 16 | 5- Way (-)|-------| | mBed |
electromotivated 0:0388385d4480 17 | | 40.0k | |
electromotivated 0:0388385d4480 18 | Tact (R)|--------vvv--------| | |
electromotivated 0:0388385d4480 19 | | 15.0k | | |
electromotivated 0:0388385d4480 20 | Switch (D)|--------vvv--------| | |
electromotivated 0:0388385d4480 21 | | 6.67k | | |
electromotivated 0:0388385d4480 22 | (L)|--------vvv--------|--------------------|AnalogIn |
electromotivated 0:0388385d4480 23 | | 2.5k | | | |
electromotivated 0:0388385d4480 24 | (C)|--------vvv--------| > | |
electromotivated 0:0388385d4480 25 | | | > 10k | |
electromotivated 0:0388385d4480 26 | (U)|-------------------| > | |
electromotivated 0:0388385d4480 27 | | | |---------
electromotivated 0:0388385d4480 28 | (+)|-----------X ---
electromotivated 0:0388385d4480 29 ---------------- GND
electromotivated 0:0388385d4480 30
electromotivated 0:0388385d4480 31 Theory of Operation: Each switch output pin is connected to one terminal of
electromotivated 0:0388385d4480 32 a resistor (each of different value). The other terminal
electromotivated 0:0388385d4480 33 is connected to a single analog in pin on the mBed.
electromotivated 0:0388385d4480 34 The mBed analog pin is also connected to a 10k resistor
electromotivated 0:0388385d4480 35 running to ground. This makes a network of seperate
electromotivated 0:0388385d4480 36 voltage dividers, between each switches output pin
electromotivated 0:0388385d4480 37 resistor and the single 10k resistor from the mBed
electromotivated 0:0388385d4480 38 analog in pin to ground. Since only one position can
electromotivated 0:0388385d4480 39 be active at a time only one voltage divider voltage
electromotivated 0:0388385d4480 40 is read by the mBed. Thus each switch position produces
electromotivated 0:0388385d4480 41 a unique voltage, at the analog in pin of the mBed,
electromotivated 0:0388385d4480 42 when active.
electromotivated 0:0388385d4480 43
electromotivated 0:0388385d4480 44 NOTE: For proper operation resistor values should be as close as POSSIBLE
electromotivated 0:0388385d4480 45 to those shown in the circuit setup diagram!
electromotivated 0:0388385d4480 46 */
electromotivated 0:0388385d4480 47 #ifndef FIVE_POS_SWITCH
electromotivated 0:0388385d4480 48 #define FIVE_POS_SWITCH
electromotivated 0:0388385d4480 49 #include "mbed.h"
electromotivated 0:0388385d4480 50
electromotivated 3:dcb9eef119cf 51 typedef enum {NONE, UP, CENTER, LEFT, DOWN, RIGHT}ACTIVE_POSITION_t;
electromotivated 0:0388385d4480 52
electromotivated 0:0388385d4480 53 class FivePosSwitch{
electromotivated 0:0388385d4480 54 public:
electromotivated 2:a415472059c3 55 /** Constructor for FivePosSwitch
electromotivated 2:a415472059c3 56 @param <pin> The AnalogIn Pin
electromotivated 2:a415472059c3 57 */
electromotivated 0:0388385d4480 58 FivePosSwitch(AnalogIn pin);
electromotivated 2:a415472059c3 59 /** Get the currently pressed switch position
electromotivated 2:a415472059c3 60 @return The currently pressed switch position
electromotivated 2:a415472059c3 61 */
electromotivated 3:dcb9eef119cf 62 ACTIVE_POSITION_t getPosition();
electromotivated 0:0388385d4480 63 private:
electromotivated 0:0388385d4480 64 AnalogIn _pin;
electromotivated 0:0388385d4480 65 static const float TOLERANCE = 0.075; // Allowable tolerance in evaluating for active switch
electromotivated 0:0388385d4480 66 // (0.075 will give a 0.05 deadband between posistions)
electromotivated 0:0388385d4480 67 };
electromotivated 0:0388385d4480 68
electromotivated 0:0388385d4480 69 #endif