john telfer

How can I adapt the basic Arduino blink sketch so that I can use max to alter the delay values of high and low?

Essentially how can I use a max patch to alter the speed and duration of the blink?

How can I adapt the basic Arduino blink sketch so that I can use max to alter the delay values of high and low?
Essentially how can I use a max patch to alter the speed and duration of the blink?
Thanks

How can I adapt the basic Arduino blink sketch so that I can use max to alter the delay values of high and low?
Essentially how can I use a 

max-to-arduino-communication

Instead of modifying delay time one should light the led directly from max.

Trying to modify delay times in the main loop

by reading serial port will give you a big headache.

Instead of modifying delay time one should light the led directly from max.
Trying to modify delay times in the main loop
by reading serial port will give you a big headache.


So ditch the Arduino and go with a DMX interface instead?

Great.  Thanks for getting back to me.
So ditch the Arduino and go with a DMX interface instead?

I believe Maxuino is still useful for this kind of stuff but support ceased a while ago.

I believe Maxuino is still useful for this kind of stuff but support ceased a while ago.
https://www.maxuino.org/video

No, I did not suggest to replace arduino.

But you can switch the led from max directly.

In a loop in arduino code delay function stops execution

of any part of loop till delay time elapses.

So it is difficult to fast read serial port to adjust delay time.

One would have to use another function with millis

Instead just send 1 or 0 from max to arduino to turn the led

But if it is meant for some more complex project, then

I would wait till you post what exactly you are planning to make.

And - stay away from maxuino or any other premade stuff which

makes it difficult to learn and troubleshoot stuff.

If you look at maxuino patch, I feel that more time has been spent 

to hide the inner working of it, than for what it does.

No, I did not  suggest to replace arduino.
But you can switch the led from max directly.
In a loop in arduino code delay function stops execution
of any part of loop till delay time elapses.
So it is difficult to fast read serial port to adjust delay time.
One would have to use another function with millis
or  similar outside of the main loop.
--------
Instead just send 1 or 0 from max to arduino to turn the led
on or off.
If you need help to do that, just post.
But if it is meant for some more complex project, then
I would wait till you post what exactly you are planning to make.
And - stay away from maxuino or any other premade stuff which
makes it difficult to learn and troubleshoot stuff.
If you look at maxuino patch, I feel that more time has been spent 
to hide the inner working of it, than for what it does.


I'm working on a cymatics project, exploring patterns of visible sound vibration in water.

https://www.youtube.com/watch?v=sThS9OfnM1s

In AfterEffects i've managed to slow these patterns down with frame displacement.

https://www.youtube.com/watch?v=ftoFKlTcYEc

In a live situation I'm trying to develop a set-up so that people can sing or play into the system and see how the vibrated water responds.

Most interesting patterns manifest within a range of 5-50hz so the input signal needs to be transposed and translated to a sine wave. Here's the Max patch I'm working on for this.

CYMATICS PITCH SHIFT AND STROBE.maxpat

In tandem with this I want the frequency of the signal to be translated to milliseconds to drive a strobe in order to slow down or freeze the extremely fast water dynamics.

So I need to find a way to communicate the variable millisecond readout in Max to an Arduino to strobe a high powered LED.

Hope this all makes some kind of sense and really appreciate any help and suggestions.

I'm working on a cymatics project, exploring patterns of visible sound vibration in water.
www.cymaticmusic.co.uk
https://www.youtube.com/watch?v=sThS9OfnM1s

In AfterEffects i've managed to slow these patterns down with frame displacement.
https://www.youtube.com/watch?v=ftoFKlTcYEc

In a live situation I'm trying to develop a set-up so that people can sing or play into the system and see how the vibrated water responds.
Most interesting patterns manifest within a range of 5-50hz so the input signal needs to be transposed and translated to a sine wave. Here's the Max patch I'm working on for this.

Hope this all makes some kind of sense and really appreciate any help and suggestions.


This all makes sense, but as I say forget sending delay time to arduino.

That makes no sense. Just light that strobe LED directly.

That would also allow to control light intensity using PWM.

On Arduino side it just needs one Mosfet or Darlington transistor.

In simplest form, just turning LED on or off,

you can use metro, set timer hz - ms and bang a toggle.

Send toggle output to arduino to power the led.

This all makes sense, but as I say forget sending delay time to arduino.
That makes no sense. Just light that strobe LED directly.
That would also allow to control light intensity using PWM.
On Arduino side it just needs one Mosfet or Darlington transistor.
In simplest form, just turning LED on or off,
you can use metro, set timer hz - ms and bang a toggle.
Send toggle output to arduino to power the led.
50 Hz = 20 ms


If only ON has to follow the frequency, but length of light has to be shorter

that could be easily done using delay in max to toggle off.

If only ON has to follow the frequency, but length of light has to be shorter
that could be easily done using delay in max to toggle off.


Great. Works fine with built in LED.
Waiting for Mosfet to arrive.
If any further issues I'll let you know.
Much appreciated

I'm not understanding how to use delay to alter the relative lengths of on and off.

If I enter 1Hz/1000ms light is on for 1000ms , off for 1000ms.

How in Max would I achieve the same effect as 10ms delay HIGH 1900ms delay LOW with Arduino?

How could I always have 10ms on regardless of off length?

How in Max would I achieve the same effect as 10ms delay HIGH 1900ms delay LOW with Arduino?
How could I always have 10ms on regardless of off length?

I've made a bit of progress - I have two sets of Max/Arduino files which work independently but don't seem to work when combined. Not sure whether it's coding errors or overloading the serial.

sine and flicker to max and back2a.maxpat

Adafruit_NeoPixel stripa = Adafruit_NeoPixel(NUM_LEDSa, PINa, NEO_RGB + NEO_KHZ800);

Adafruit_NeoPixel stripb = Adafruit_NeoPixel(NUM_LEDSb, PINb, NEO_RGB + NEO_KHZ800);

2swatchmax.maxpat

Adafruit_NeoPixel stripa = Adafruit_NeoPixel(NUM_LEDSa, PINa, NEO_GRB + NEO_KHZ800);

Adafruit_NeoPixel stripb = Adafruit_NeoPixel(NUM_LEDSb, PINb, NEO_GRB + NEO_KHZ800);

uint32_t hue1 = stripa.Color(redVala, greenVala, blueVala);

uint32_t hue2 = stripb.Color(redValb, greenValb, blueValb);

sine and flicker to max and back + swatch.maxpat

uint32_t hue3 = stripb.Color(redValb, greenValb, blueValb);

Hello again,
I've made a bit of progress - I have two sets of Max/Arduino files which work independently but don't seem to work when combined. Not sure whether it's coding errors or overloading the serial.
The files which work are:

#define PINa 3
#define PINb 5
#define POT_PINa A3
#define POT_PINb A4
#define NUM_LEDSa 8
#define NUM_LEDSb 8
int potfPin=A2;
int potsPin=A5;
int potfVal;
int potsVal;
int MaxfVal;
int MaxsVal;

Adafruit_NeoPixel stripa = Adafruit_NeoPixel(NUM_LEDSa, PINa, NEO_RGB + NEO_KHZ800);
Adafruit_NeoPixel stripb = Adafruit_NeoPixel(NUM_LEDSb, PINb, NEO_RGB + NEO_KHZ800);

uint32_t hue1 = stripa.Color(0, 255, 0);
uint32_t hue2 = stripa.Color(0, 0, 0);
uint32_t hue3 = stripb.Color(0, 0, 255);
uint32_t hue4 = stripb.Color(0, 0, 0);

Serial.begin(9600);
  pinMode (potfPin,INPUT);
pinMode (potsPin,INPUT);
pinMode (POT_PINa,INPUT);
pinMode (POT_PINb,INPUT);
 

 stripa.begin();
 stripa.show(); 
  stripa.setBrightness(255);

 stripb.begin();
 stripb.show(); 
  stripb.setBrightness(255);   
}

potfVal=analogRead(potfPin);
potsVal=analogRead(potsPin);
MaxfVal=map(potfVal,0, 509, -509, 0);
MaxsVal=map(potsVal,0, 1023, 1, 1024);
Serial.print(MaxfVal);
Serial.print(" ");
Serial.println(MaxsVal);   
    if (Serial.available() > 0) {
 

}int Light = Serial.parseInt();
 if (Light == 1) {stripa.fill(hue1); 
 stripb.fill(hue3);}
else {stripa.fill(hue2);
stripb.fill(hue4);}
 stripa.show(); 
 stripb.show();
}

//define NeoPixel Pin and Number of LEDs
#define PINa 3
#define PINb 5
#define NUM_LEDSa 8
#define NUM_LEDSb 8
int redVala = 0;
int redValb = 0;
int greenVala = 0;
int greenValb = 0;
int blueVala = 0;
int blueValb = 0;
Adafruit_NeoPixel stripa = Adafruit_NeoPixel(NUM_LEDSa, PINa, NEO_GRB + NEO_KHZ800);
Adafruit_NeoPixel stripb = Adafruit_NeoPixel(NUM_LEDSb, PINb, NEO_GRB + NEO_KHZ800);

void setup() {
  // start the strip and blank it out
  Serial.begin(9600);
  stripa.begin();
  stripb.begin();
 stripa.show();
 stripb.show();
  stripa.setBrightness(255);
  stripb.setBrightness(255);
}

void loop() {
if (Serial.available() > 0) {
 redVala = Serial.parseInt();
  greenVala = Serial.parseInt();
  blueVala = Serial.parseInt();
  redValb = Serial.parseInt();
  greenValb = Serial.parseInt();
  blueValb = Serial.parseInt();
 

   }
 uint32_t hue1 = stripa.Color(redVala, greenVala, blueVala);
uint32_t hue2 = stripb.Color(redValb, greenValb, blueValb);

stripa.fill(hue1);
stripb.fill(hue2);
 stripa.show();  
 stripb.show(); 
    }

#define PINa 3
#define PINb 5
#define POT_PINa A3
#define POT_PINb A4
#define NUM_LEDSa 8
#define NUM_LEDSb 8
int potfPin=A2;
int potsPin=A5;
int potfVal;
int potsVal;
int MaxfVal;
int MaxsVal;
int redVala = 0;
int redValb = 0;
int greenVala = 0;
int greenValb = 0;
int blueVala = 0;
int blueValb = 0;

potfVal=analogRead(potfPin);
potsVal=analogRead(potsPin);
MaxfVal=map(potfVal,0, 509, -509, 0);
MaxsVal=map(potsVal,0, 1023, 1, 1024);
Serial.print(MaxfVal);
Serial.print(" ");
Serial.println(MaxsVal);   
    if (Serial.available() > 0) {
      redVala = Serial.parseInt();
  greenVala = Serial.parseInt();
  blueVala = Serial.parseInt();
  redValb = Serial.parseInt();
  greenValb = Serial.parseInt();
  blueValb = Serial.parseInt();
 

}
  uint32_t hue1 = stripa.Color(redVala, greenVala, blueVala);
uint32_t hue2 = stripa.Color(0, 0, 0);
uint32_t hue3 = stripb.Color(redValb, greenValb, blueValb);
uint32_t hue4 = stripb.Color(0, 0, 0);

int Light = Serial.parseInt();
 if (Light == 1) {stripa.fill(hue1); 
 stripb.fill(hue3);}
else {stripa.fill(hue2);
stripb.fill(hue4);}
 stripa.show(); 
 stripb.show();
}

as first you should not use 2 serial objects to talk to same hardware in Max Patch.

And baud rate of 9600 could maybe be too slow, depending on speed and amount of data

Then, there is a lot to improve in that max patches,

Screen shot 2021-04-04 at 9.19.36 AM.png

using metro you send that list 20 times per second even if nothing changed,

inserting zl change would at least prevent resending of same list.

or remove metro etc and use speedlim and output the list when swatches change values.

You need to look at every item you send from Max to arduino, and the opposite way as well to avoid unneeded data flow.

That last patch can't be downloaded, maybe error in the name ...

At least in simple patches , one should avoid encapsulating stuff into

Later if things get complex, it surely is a good practice.

I am not sure if you want to adjust 2 swatches from time to time,

and blink the Leds, or you want to allways combine blinking with set swatch values, which makes less sense.

But it makes a big difference to the whole construct.

Let's say you want to keep lights on without blinking,

You would need to stop metro, send Light 1, and then move the swatches.

That would mean that parsing Light should be a separated process.

To distinguish it form the swatches list, I would suggest prepending a letter

Next thing is - try to send pot values only if their values changed.

as first you should not use 2 serial objects to talk to same hardware in Max Patch.
And baud rate of 9600 could maybe be too slow, depending on speed and amount of data
transfered.

Then, there is a lot to improve in that max patches,
let's  have a look at one of them



using metro you send that list 20 times per second even if nothing changed,
inserting zl change would at least prevent resending of same list.
or remove metro etc and use speedlim and output the list when swatches change values.

You need to look at every item you send from Max to arduino, and the opposite way as well to avoid unneeded data flow.
----
That last patch can't be downloaded, maybe error in the name ...

At least in simple patches , one should avoid encapsulating stuff into
bpatchers, to have a better overwiew.
Later if things get complex, it surely is a good practice.
--------
This :

if (Serial.available() > 0) {
  redVala = Serial.parseInt();
  greenVala = Serial.parseInt();
  blueVala = Serial.parseInt();
  redValb = Serial.parseInt();
  greenValb = Serial.parseInt();
  blueValb = Serial.parseInt();
 }
uint32_t hue1 = stripa.Color(redVala, greenVala, blueVala);
uint32_t hue2 = stripa.Color(0, 0, 0);
uint32_t hue3 = stripb.Color(redValb, greenValb, blueValb);
uint32_t hue4 = stripb.Color(0, 0, 0);
int Light = Serial.parseInt();
 if (Light == 1) {stripa.fill(hue1); 
 stripb.fill(hue3);}
else {stripa.fill(hue2);
stripb.fill(hue4);}
 stripa.show(); 
 stripb.show();
-----
is not going to work.
I am not sure if you want to adjust 2 swatches from time to time,
and blink the Leds, or you want to allways combine blinking with set swatch values, which makes less sense.
But it makes a big difference to the whole construct.
Let's say you want to keep lights on without blinking,
and change colours.
You would need to stop metro, send Light 1, and then move the swatches.
That would mean that parsing Light should be a separated process.
To distinguish it form the swatches list, I would suggest prepending a letter
to it like L
Here is max patch


Reduced to only needed things.
------
Next thing is - try to send pot values only if their values changed.
You can do the scaling in Max


Really appreciate your help. Very instructive .

I'll work through your advice over the next few days.

I've isolated the swatch to serial part of your new patch.

cymaxard1aa.maxpat

The two led strips light up fine but turn off after 7 seconds. Any ideas? They didn't with my patch.

The two led strips light up fine but turn off after 7 seconds.  Any ideas?  They didn't with my patch.

you must post arduino sketch for exactly and ONLY this patch,

I guess serial parsing int sends zero after not received valid int after a while

which should be 1000 ms , but not 7 seconds ...

you must post arduino sketch for exactly and ONLY this patch,
nothing else inside.
I guess serial parsing int sends zero after not received valid int after a while
which should be 1000 ms , but not 7 seconds ...


I tried to simplify the whole on both sides, there is only 1 list sent to arduino :

I hope it should work, have no LED stripes for testing though...

there is Threshold value set to 5 so that pots only send if changed more than set value,

and scaling of pot values is done in max.

You can increase delay time at the end to more than 10 ms if you don't need that

All the pins remained as in your patch, not used ones got removed....

int potfVal = 0; int EXpotfVal = 0; int potsVal = 0; int EXpotsVal = 0;

int THRESH = 5; // Pot Value change threshold

uint32_t hue1; uint32_t hue2; uint32_t hue3; uint32_t hue4;

Adafruit_NeoPixel stripa = Adafruit_NeoPixel(8, 3, NEO_RGB + NEO_KHZ800); 

Adafruit_NeoPixel stripb = Adafruit_NeoPixel(8, 4, NEO_RGB + NEO_KHZ800);

Serial.begin(9600); pinMode (3,INPUT); pinMode (4,INPUT); //strip a & b PINS 

int potfVal = analogRead(A2); if(abs(potfVal - EXpotfVal) > THRESH) {Serial.print("F "); Serial.println(potfVal); EXpotfVal = potfVal;}

int potsVal=analogRead(A5); if(abs(potsVal - EXpotsVal) > THRESH) {Serial.print("S ");Serial.println(potsVal); EXpotsVal = potsVal;}

int redVala = Serial.parseInt(); int greenVala = Serial.parseInt(); int blueVala = Serial.parseInt();

int redValb = Serial.parseInt(); int greenValb = Serial.parseInt(); int blueValb = Serial.parseInt();

if (Light == 1) {stripa.fill(hue1); stripb.fill(hue2);}

else {stripa.fill(hue3); stripb.fill(hue4);}

I tried to simplify the whole on both sides, there is only 1 list sent to arduino :
Switch and 6 swatch values.
I hope it should work, have no LED stripes for testing though...

there is Threshold value set to 5 so that pots only send if changed more than set value,
and scaling of pot values is done in max.
You can increase delay time at the end to more than 10 ms if you don't need that
fast running loop.
All the pins remained as in your patch, not used ones got removed....


int potfVal = 0; int EXpotfVal = 0; int potsVal = 0; int EXpotsVal = 0;
int THRESH = 5; // Pot Value change threshold
uint32_t hue1; uint32_t hue2; uint32_t hue3; uint32_t hue4;

Adafruit_NeoPixel stripa = Adafruit_NeoPixel(8, 3, NEO_RGB + NEO_KHZ800); 
Adafruit_NeoPixel stripb = Adafruit_NeoPixel(8, 4, NEO_RGB + NEO_KHZ800);

void setup() {
Serial.begin(9600); pinMode (3,INPUT); pinMode (4,INPUT); //strip a & b PINS 
stripa.begin(); stripa.show(); stripa.setBrightness(255);
stripb.begin(); stripb.show();  stripb.setBrightness(255);   
}
void loop() {
int potfVal = analogRead(A2); if(abs(potfVal - EXpotfVal) > THRESH) {Serial.print("F "); Serial.println(potfVal); EXpotfVal = potfVal;}
int potsVal=analogRead(A5); if(abs(potsVal - EXpotsVal) > THRESH) {Serial.print("S ");Serial.println(potsVal); EXpotsVal = potsVal;}
 

if (Serial.available() > 0) {
int Light = Serial.parseInt();
int  redVala = Serial.parseInt(); int  greenVala = Serial.parseInt(); int  blueVala = Serial.parseInt();
int  redValb = Serial.parseInt(); int  greenValb = Serial.parseInt(); int  blueValb = Serial.parseInt();
if (Serial.read() == '\n') {
uint32_t hue1 = stripa.Color(redVala, greenVala, blueVala);
uint32_t hue2 = stripb.Color(redValb, greenValb, blueValb);
uint32_t hue3 = stripa.Color(0, 0, 0);
uint32_t hue4 = stripb.Color(0, 0, 0);
if (Light == 1) {stripa.fill(hue1); stripb.fill(hue2);}
else {stripa.fill(hue3); stripb.fill(hue4);}
stripa.show(); stripb.show();
}}
delay(10);}

Just one more piece of the puzzle to sort out.

I need an option for a audio signal input which can be pitch shifted and can trigger cycle to output a matching pitch frequency (retune@pitchdetection I've been told should do it).

I'll give it my best shot but may well have to reutilise your expertise at some point!

There are quite few pitch detectors out there,

it is as simple to use as it can be, and performs great.

You allow only expected output frequency to pass,

and control output volume using either it's amp output or simply meter~

any pitch detector would do, I am just fan of this one for it's simplicity and performance.

There are quite few pitch detectors out there,
If you are using Mac,  try vb.pitch~ 
https://vboehm.net/downloads/
it is as simple to use as it can be, and performs great.
You allow only expected output frequency to pass,
and control output volume using either it's amp output or simply meter~

any pitch detector would do, I am just fan of this one for it's simplicity and performance.


I want to add two pots to fade the led strips in and out.

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDSa, PINa, NEO_RGB + NEO_KHZ800);

Adafruit_NeoPixel strip2 = Adafruit_NeoPixel(NUM_LEDSb, PINb, NEO_RGB + NEO_KHZ800);

uint32_t hue2 = strip2.Color(0, 255, 255);

uint16_t potReada = analogRead(POT_PINa);

uint8_t brightnessa = map(potReada, 0, 1023, 0, 255);

uint16_t potReadb = analogRead(POT_PINb);

uint8_t brightnessb = map(potReadb, 0, 1023, 0, 255);

but when I try incorporating it into the main patch it stops working.

Adafruit_NeoPixel stripa = Adafruit_NeoPixel(37, 5, NEO_RGB + NEO_KHZ800); 

Adafruit_NeoPixel stripb = Adafruit_NeoPixel(40, 3, NEO_RGB + NEO_KHZ800);

pinMode (5,INPUT); pinMode (3,INPUT); //strip a & b PINS 

int potfVal = analogRead(A4); if(abs(potfVal - EXpotfVal) > THRESH) {Serial.print("F "); Serial.println(potfVal); EXpotfVal = potfVal;}

#define PINa 3
#define PINb 5
#define POT_PINa A2
#define POT_PINb A0
#define NUM_LEDSa 8
#define NUM_LEDSb 8

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDSa, PINa, NEO_RGB + NEO_KHZ800);
Adafruit_NeoPixel strip2 = Adafruit_NeoPixel(NUM_LEDSb, PINb, NEO_RGB + NEO_KHZ800);

uint32_t hue1 = strip.Color(0, 255, 0);
uint32_t hue2 = strip2.Color(0, 255, 255);

pinMode (POT_PINa,INPUT);
pinMode (POT_PINb,INPUT);
 

 strip.begin();
 strip.show(); 
  strip.setBrightness(255);

 strip2.begin();
 strip2.show(); 
  strip2.setBrightness(255);   
}

uint16_t potReada = analogRead(POT_PINa);
uint8_t brightnessa = map(potReada, 0, 1023, 0, 255);
strip.setBrightness(brightnessa);

uint16_t potReadb = analogRead(POT_PINb);
uint8_t brightnessb = map(potReadb, 0, 1023, 0, 255);
strip2.setBrightness(brightnessb);

strip.fill(hue1);
strip2.fill(hue2);
 strip.show(); 
 strip2.show();
} 

#include <Adafruit_NeoPixel.h>
#define POT_PINa A0
#define POT_PINb A2
int potfVal = 0; int EXpotfVal = 0; int potsVal = 0; int EXpotsVal = 0;
int THRESH = 5; // Pot Value change threshold
uint32_t hue1; uint32_t hue2; uint32_t hue3; uint32_t hue4;
Adafruit_NeoPixel stripa = Adafruit_NeoPixel(37, 5, NEO_RGB + NEO_KHZ800); 
Adafruit_NeoPixel stripb = Adafruit_NeoPixel(40, 3, NEO_RGB + NEO_KHZ800);
void setup() {
Serial.begin(9600); 
pinMode (POT_PINa,INPUT);
pinMode (POT_PINb,INPUT);
pinMode (5,INPUT); pinMode (3,INPUT); //strip a & b PINS 
stripa.begin(); stripa.show(); stripa.setBrightness(255);
stripb.begin(); stripb.show();  stripb.setBrightness(255);   
}
void loop() {

int potfVal = analogRead(A4); if(abs(potfVal - EXpotfVal) > THRESH) {Serial.print("F "); Serial.println(potfVal); EXpotfVal = potfVal;}
int potsVal=analogRead(A5); if(abs(potsVal - EXpotsVal) > THRESH) {Serial.print("S ");Serial.println(potsVal); EXpotsVal = potsVal;}
 

if (Serial.available() > 0) {
int Light = Serial.parseInt();
int  redVala = Serial.parseInt(); int  greenVala = Serial.parseInt(); int  blueVala = Serial.parseInt();
int  redValb = Serial.parseInt(); int  greenValb = Serial.parseInt(); int  blueValb = Serial.parseInt();
if (Serial.read() == '\n') {
uint32_t hue1 = stripa.Color(redVala, greenVala, blueVala);
uint32_t hue2 = stripb.Color(redValb, greenValb, blueValb);
uint32_t hue3 = stripa.Color(0, 0, 0);
uint32_t hue4 = stripb.Color(0, 0, 0);
if (Light == 1) {stripa.fill(hue1); stripb.fill(hue2);}
else {stripa.fill(hue3); stripb.fill(hue4);}

uint16_t potReada = analogRead(POT_PINa);
uint8_t brightnessa = map(potReada, 0, 1023, 0, 255);
stripa.setBrightness(brightnessa);

uint16_t potReadb = analogRead(POT_PINb);
uint8_t brightnessb = map(potReadb, 0, 1023, 0, 255);
stripb.setBrightness(brightnessb);

stripa.show(); stripb.show();
}}
delay(10);}

Are you maybe complicating too much with all that 

uint16_t potReada = analogRead(POT_PINa); 

uint8_t brightnessa = map(potReada, 0, 1023, 0, 255); 

uint16_t potReadb = analogRead(POT_PINb); 

uint8_t brightnessb = map(potReadb, 0, 1023, 0, 255); 

because then pots will get read only while serial port is receiving.

int brightA = analogRead(A2/4); stripa.setBrightness(brightA);

int brightB = analogRead(A0/4); stripb.setBrightness(brightB);

Are you maybe complicating too  much with all that #define POT and uint whatever  stuff ?

All this is not needed at all:

#define POT_PINa A2 
#define POT_PINb A0

pinMode (POT_PINa,INPUT);
pinMode (POT_PINb,INPUT);

uint16_t potReada = analogRead(POT_PINa); 
uint8_t brightnessa = map(potReada, 0, 1023, 0, 255); 
stripa.setBrightness(brightnessa);

uint16_t potReadb = analogRead(POT_PINb); 
uint8_t brightnessb = map(potReadb, 0, 1023, 0, 255); 
stripb.setBrightness(brightnessb);
----------------
put this into loop but NOT inside if (Serial .available ...
because then pots will get read only while serial port is receiving.

int brightA = analogRead(A2/4); stripa.setBrightness(brightA);
int brightB = analogRead(A0/4); stripb.setBrightness(brightB);


depending on where brightness stuff got inserted.

Another option would be to send brightness pot values A & B to Max

and scale the RGB values there before they get sent to Arduino.

P.S. maybe you need to add 
stripa.show(); stripb.show();  after setting the brightness,
depending on where brightness stuff got inserted.

Another option would be to send brightness pot values A & B to Max
and scale the RGB values there before they get sent to Arduino.



Programming the two pots via only Arduino doesn't seem to work.

max to Arduino communication