John Donnal / Tach

Interface with a single channel encoder (eg IR emitter/detector on a slotted wheel). Requires a digital input and counts per revolution. Provides speed in Hz

Dependents:   ES202FinalProject ES202_straight1 ES202_Final_Turn ES202_Turn ... more

Tach.cpp@0:c165325c9e3f, 2018-03-02 (annotated)

Committer:
jdonnal
Date:
Fri Mar 02 16:52:58 2018 +0000
Revision:
0:c165325c9e3f
Initial Commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jdonnal 0:c165325c9e3f 1 #include "Tach.h"
jdonnal 0:c165325c9e3f 2
jdonnal 0:c165325c9e3f 3 //64 counts per rev
jdonnal 0:c165325c9e3f 4
jdonnal 0:c165325c9e3f 5 Tach::Tach(PinName input,
jdonnal 0:c165325c9e3f 6 int pulsesPerRev): input_(input){
jdonnal 0:c165325c9e3f 7 speed_ = 0.0;
jdonnal 0:c165325c9e3f 8 pulsesPerRev_ = pulsesPerRev;
jdonnal 0:c165325c9e3f 9 input_.mode(PullUp);
jdonnal 0:c165325c9e3f 10 input_.rise(this, &Tach::update);
jdonnal 0:c165325c9e3f 11 //input_.fall(this, &Tach::update);
jdonnal 0:c165325c9e3f 12 timer_.start();
jdonnal 0:c165325c9e3f 13 for(int i=0;i<NSAMP;i++){
jdonnal 0:c165325c9e3f 14 speedBuffer_[i]=0.0;
jdonnal 0:c165325c9e3f 15 }
jdonnal 0:c165325c9e3f 16 }
jdonnal 0:c165325c9e3f 17 int Tach::getCount(void){
jdonnal 0:c165325c9e3f 18 return count_;
jdonnal 0:c165325c9e3f 19 }
jdonnal 0:c165325c9e3f 20 float Tach::getSpeed(void) {
jdonnal 0:c165325c9e3f 21
jdonnal 0:c165325c9e3f 22 float acc=0;
jdonnal 0:c165325c9e3f 23 for(int i=0;i<NSAMP;i++){
jdonnal 0:c165325c9e3f 24 acc+=speedBuffer_[i];
jdonnal 0:c165325c9e3f 25 }
jdonnal 0:c165325c9e3f 26 return acc/NSAMP;
jdonnal 0:c165325c9e3f 27
jdonnal 0:c165325c9e3f 28 }
jdonnal 0:c165325c9e3f 29
jdonnal 0:c165325c9e3f 30 void Tach::update(void) {
jdonnal 0:c165325c9e3f 31 float speed;
jdonnal 0:c165325c9e3f 32 static int i=0;
jdonnal 0:c165325c9e3f 33 count_++;
jdonnal 0:c165325c9e3f 34 speed = 1.0/(timer_.read()*pulsesPerRev_);
jdonnal 0:c165325c9e3f 35 speedBuffer_[i%NSAMP]=speed;
jdonnal 0:c165325c9e3f 36 i++;
jdonnal 0:c165325c9e3f 37 timer_.reset();
jdonnal 0:c165325c9e3f 38 }