IoTBATTLESHIP!

This is your standard game of battleship, each player starts with five ships that are equipped with capacitors on each space the ship takes up.

IoT Battleship — Photon 2 Build Plan

Overview

Two identical boards, one per player, each run by a Photon 2. They play over the Particle cloud with publish/subscribe, so the boards can sit across the table or across town.

Each board has two 10×10 LED grids: an Ocean grid showing your own fleet and incoming hits, and a Target grid showing your shots at the opponent. You move a cursor with a rotary encoder, press to fire, and the shot travels to the other board.

How a turn plays out

• Player A picks a cell on the Target grid and presses Fire.
• Board A publishes the shot; Board B checks it against its hidden fleet.
• Board B replies HIT, MISS or SUNK; both boards animate the result.
• On SUNK, Board B fires the full explosion on that ship's pop-up hatch.

The explosion (no real detonation)

Nothing actually blows up. Each sunk ship gets layered effects that read as an explosion:

• A capacitor-discharge solenoid kick — a charged 2200 µF bank dumps into a solenoid for a sharp physical thump under the board. This is where your capacitors do the work.
• A servo-released pop-up hatch that flips the ship model up or tips it over.
• A fire-and-smoke LED burst on the ship's cells plus a strobe ring.
• An explosion sound through a speaker, and a rumble motor.
• Optional water-mist "smoke" from an ultrasonic mist module lit orange from below.

Enclosure and lid: a 3 mm clear acrylic top sheet over the diffuser protects the LEDs and gives a clean game surface. Leave the electronics bay vented with a removable panel so the mist module, servos and caps stay reachable. The pop-up ships sit in cutouts in the lid so their hatches can flip.

Firmware architecture and cloud events

One firmware image runs on both boards; each board keeps its own fleet secret and only ever publishes shots and results. Animations run off millis() so input, cloud events and effects never block each other.

Game states: BOOT → PLACE_SHIPS → WAIT_READY → MY_TURN ⇄ THEIR_TURN → GAME_OVER. The board with the lower device ID shoots first.

Libraries: Particle's neopixel for the grids, an Adafruit PCA9685 servo-driver port for the hatches, and a DFPlayer library (or the module's simple serial commands sent directly).

Boom driver with the safety limits built in:

const int BOOM_PIN = D6;
const uint32_t BOOM_PULSE_MS = 40;
const uint32_t BOOM_MAX_MS = 60;      // hard ceiling
const uint32_t BOOM_COOLDOWN_MS = 1000;

uint32_t boomStart = 0, lastBoom = 0;
bool boomOn = false;

bool fireBoom() {
  if (boomOn || millis() - lastBoom < BOOM_COOLDOWN_MS) return false;
  digitalWrite(BOOM_PIN, HIGH);
  boomOn = true;
  boomStart = lastBoom = millis();
  return true;
}

void serviceBoom() {              // call every loop()
  if (boomOn) {
    uint32_t on = millis() - boomStart;
    if (on >= BOOM_PULSE_MS || on >= BOOM_MAX_MS) {
      digitalWrite(BOOM_PIN, LOW);
      boomOn = false;
    }
  }
}

void setup() {
  pinMode(BOOM_PIN, OUTPUT);
  digitalWrite(BOOM_PIN, LOW);    // gate held low from boot
}

Optional phone control: expose a Particle.function("fire") so a player can fire from the Particle app or a small web page instead of the encoder.

Build phases

Build one board end to end on the bench before cutting materials for the second; each phase ends with something you can test.

• 1. Grid on the bench: one 10×10 serpentine grid on the Photon 2 through the level shifter; ripple, cursor and fire animations running.
• 2. Input + local game: encoder and FIRE button, ship placement with rotate and overlap checks, a single-board game against a hard-coded fleet.
• 3. Cloud play: two Photon 2s trading shot and result events; full game across two breadboards.
• 4. Boom circuit: build the bank on its own with a meter; check polarity, bleed-down time and pulse limits before wiring it to the Photon 2.
• 5. Ships and effects: servo hatches, sound, rumble and mist sequenced into the explosion timeline.
• 6. Enclosure: frame, egg-crate grid, diffuser, 3 mm acrylic lid with ship cutouts, vented service panel, fused power entry.
• 7. Second board + playtest: duplicate, flash the same firmware, tune brightness, volume and the boom pulse.