% calculate motor speed
% input file: time differences between encoder ticks in micro seconds

% 2024-06-27 Christoph M. 

x=csvread("timeBetweenEncoderTicks_us_3p4V_560mA.txt");
#x=csvread("timeBetweenEncoderTicks_us_3p4V_600mA.txt");

# create time axis from delta t's
t=cumsum(x)/1e6;

# remove values less than 1000us because the are disturbances
cleanIdx=x<1000;
t(cleanIdx)=[];
x(cleanIdx)=[];

# moving average over 24 ticks to smooth encoder slot variations
wndw = 24;  %# sliding window size
x = filter(ones(wndw,1)/wndw, 1, x);

#remove run in of moving average
t=t(wndw:end);
x=x(wndw:end);

if 0
#subplot(2,1,1);
plot(x);
xlabel("n");
ylabel("dt [us]");
ylim([0,10000]);
end

if 1
#subplot(2,1,2);

encoderTicks=24;
measuredFrequency_Hz=1e6./x;
rounds_per_sec=measuredFrequency_Hz/encoderTicks
RPM=rounds_per_sec*60
plot(t,RPM);
title("motor speed supply 3.4V on/off")
xlabel("time [s]");
ylabel("RPM");
ylim([0,2000])
grid;
end