Hi all ! sorry for the delay.
so,
@LarryD:
I don't know if it's going to be enough, but here are some pictures & my code (everything useless is commented)
// Pins
int mode = 2;
int respawn = 3;
int delai = A0;
int active = 4;
int desactive = 5;
int touche = 6;
int desactiveDuree = A1;
// Variables
int dernierRespawn = 0;
void setup() {
Serial.begin(9600);
pinMode(mode, INPUT);
pinMode(respawn, OUTPUT);
pinMode(delai, INPUT);
pinMode(active, INPUT_PULLUP);
pinMode(desactive, OUTPUT);
pinMode(touche, INPUT_PULLUP);
pinMode(desactiveDuree, INPUT);
}
void loop() {
//digitalWrite(respawn, LOW);
digitalWrite(respawn, HIGH);
// Respawn
/*if (millis() > dernierRespawn + 1000 + map(analogRead(delai), 0, 1023, 0, 10000)) { // De 1s à 11s
dernierRespawn = millis();
digitalWrite(respawn, HIGH);
delay(250);
}
// Touche (désactivation)
if (1-digitalRead(touche)) {
digitalWrite(respawn, LOW);
digitalWrite(desactive, HIGH);
delay(10000 + map(analogRead(desactiveDuree), 0, 1023, 0, 100000)); // De 10s à 110s
dernierRespawn = millis();
} else {
digitalWrite(desactive, LOW);
}*/
}
board here :
Do not do that! It will damage the LEDs and possibly the Arduino pins.
Note. 
@JohnRob:
Thank you for all this information & the diagram on the voltage drop, on a previous assembly (this one is only my second), I had no problem with the leds (the same ones). And with equivalent resistances. Here the problem is precisely that with 150Ohm, the lighting is 10% of normal (compared to a direct 5V power supply & with the resistor).
If I connect the + to the 5V output of the arduino, same result, it lights up very badly.
I tested with another Uno card, same thing.
I just went to look for other resistors, I get normal lighting at 100 Ohm, but I find it strange on the internet we see everyone putting 220?
You didn't show your calculations tell us the resistance. ...For a 2V LED at 20mA you have 3V across the resistor so 3V/0.02A =150 Ohms. Is that what you're using?
Yes and it's too much. 100 is fine.
And if you measure the current you are probably exceeding the specs for the LED and the Arduino! 
It might work OK or one or both may eventually die, or the Arduino may become flakey when the LED is on.
My father explained to me afterwards that tension and charge were linked but I still have a little trouble with that.
Well I wouldn't do it again anyway. 
A common mistake is not setting the pin to OUTPUT in setup()
Yes I had suspected when several people asked me that it must be something like that, no my PIN is correctly configured
Of course since neither code nor the result of the supposed calculation was given, we so far do not - cannot - know.
Yes I should have, I'm not sure why I didn't post at least the code from the beginning, it's stupid. 
I use this site to calculate the resistance of my leds:
for the blue, it gives me 100 Ohm
for red, 150 Ohm
It's too much for red.
And in general people take a value a little above. There I even have to take a little below to be good.
I no longer have access to the LEDs page, they are 3mm bought on aliexpress, nothing very high-end.
thank you all for your attention and the time you spent answering me, in itself I can put 100Ohm everywhere, but I find it counter-intuitive to have no safety margin, or even to reduce it in the case of red.
(or else the specs of my leds are wrong).
