How to better control an RGBLED with a colormap array?

What I need it to do, is to have my led change colors based off the temperature (or voltage) with the colors of jet. As of right now, running the latter I get an error saying Index in position 1 exceeds array bounds (must not exceed 1). Error in capstone (line 43). red = cmap(gn, 1);

I can get my plot to work fine beforehand, but I am at a loss for how to fix this. I'm attempting to have my colormap in an array of size 256 where each column is a color, for each rgbLED color. my cmap equation came from taking my highest voltage and lowest voltage as points and creating an equation. IE (.3,0) is low for blue and (.8, 256) is high for red.

This is with arduino uno r3 and matlab. No simulink

This is my code before tinkering with it:

cmap = jet(256); % 3 rows by 256 columns for color (red , green, blue) %defines the colormap and number of the entries with max %256

interv = 500;

initialTime=1;

x=0;

while (initialTime<interv)

v = readVoltage(a, 'A0');

cmap = 582v -192;

if v < .33 %if voltage is lower than whats allowed, set the %value above the lowest

v= .34;

end

if v > .77 %if voltage is higher than whats allowed, set the %value lower the highest

v = .76;

end

writePWMVoltage(a, 'D6', v); %blue

writePWMVoltage(a, 'D9', v); %green

writePWMVoltage(a, 'D5', v); %red

tempC = (v-.5)35;

tempF = tempC*9/5 + 32;

x=[x,tempF];

xlim([0 150])

grid ON

plot(x)

title('Voltages Recorded from Thermistor')

xlabel('Time(sec)')

ylabel('Temperature (F)')

initialTime=initialTime+1; drawnow

end

Here is some code with changes:

a = arduino;

%v = readVoltage(a,'A0');

%finds the resistance of the thermistor

voltRead = readVoltage(a,'A0');

voltTotal = 5;

volt = voltTotal-voltRead;

amps = voltRead/9750;

res = volt/amps;

% 3 rows by 256 columns for color (red , green, blue)

%defines the colormap and number of the entries with max 256

colormap jet;

cmap = jet(256);

colorbar;

colormap(gca, cmap);

green = 1; %greenLED

blue=1;

red=1;

gn = 0;

%Runs for 500 intervals

interv = 500;

initialTime=1;

x=0;

while (initialTime<interv)

v = readVoltage(a, 'A0');

%tempC = (v-.5)*35;

temp = (v*500)/1023;

tempF = temp*9/5 + 32;

cmap = 582*v -192;

gn = round(cmap, 0);

red = cmap(gn, 1);

green = cmap(gn, 2);

blue = cmap(gn, 3);

%if voltage is lower than whats allowed, set the

%value above the lowest

if v < .33

v= .34;

end

%if voltage is higher than whats allowed, set the

%value lower the highest

if v > .77

v = .76;

end

jetTemp = round((tempF - 32)*3.764);

jetTempRGB = jetTemp +30;

%removes error possibility of being over the array limit

if jetTempRGB > 256

jetTempRGB = 256;

end

writePWMVoltage(a, 'D6', cmap(jetTempRGB, 1)); %blue

writePWMVoltage(a, 'D9', cmap(jetTempRGB, 2)); %green

writePWMVoltage(a, 'D5', cmap(jetTempRGB, 3)); %red

x=[x,tempF];

xlim([0 150])

grid ON

plot(x)

title('Voltages Recorded from Thermistor')

xlabel('Time(sec)')

ylabel('Temperature (F)')

initialTime=initialTime+1;

drawnow

end