55: Use a Photon as an Arduino

"Arduino Mode": Who needs it? Well, I have -- a couple of times. Here are some reasons:

3. A Photon is a 32-bit computer. It is 2x+ faster and has 4x program memory. About the same footprint as an Arduino Nano.

2. Photon analog ports are 12 bits to Arduino's 10 bits = higher resolution readings.

1. Most important: So you can test a Photon setup before Internet has been installed. This is why I've needed Arduino-mode!

I recently had to try a Photon setup "out in the field" and ended up reprogramming it for a Nano. I commented out the Cloud stuff, re-did the analog values, found that I had an "int" overflow (changed it to "long". And had to move the breadboard wires to fit the Nano (and later back for the Photon).

So I complained to Particle and was advised to try MANUAL mode, like this--

SYSTEM_MODE(MANUAL); // this kludge has to be before setup()

void setup() {
    Serial.begin(9600); // you'll need to talk to it
    . . .
}

void loop() {

    . . .
    if(!Serial.available()) {
        delay(1000); // some number
        return;
    }
    // read a command
    ch = Serial.read(); // get 1st character
    if(ch == 'c') { // some value: switch back to connected
        // so you can later flash new code without reset
        Particle.connect();
    }
    . . .

So, for $19 you can have a bigger, better Nano.