Simple Light Module (Arduino)

This module controls a relay connected to a lamp via serial commands. It supports:

Manual control (led: true/false)
Scheduled on/off (on_time, off_time)
Automatic priority (time-based control overrides manual)

🔌 Hardware requirements

Microcontroller: Arduino Nano / Uno / ESP32 (serial mode)
1-channel relay (5V)
Connected load (e.g., 220V lamp)
Serial communication from Node-RED or backend

📡 Serial communication

The device receives JSON over Serial (9600 baud). Each message ends with \n.

Expected payload:

{
  "current_time": "HH:MM",
  "on_time": "HH:MM",
  "off_time": "HH:MM",
  "led": true | false
}
````

> **Note:**
>
> * `current_time` is required for scheduling.
> * `led` triggers manual control, but will be overridden by the schedule if active.

---

## 🧠 Control priority

| Condition               | Relay state        |
| ----------------------- | ------------------ |
| Within scheduled time   | Relay ON (`LOW`)   |
| Outside time + override | Use `led` value    |
| Outside time            | Relay OFF (`HIGH`) |

---

## 🔄 Typical flow (via Node-RED)

```text
[ Inject ] → [ Function Node ] → [ Serial Out ]

Example function (JavaScript):

let now = new Date();
now.setHours(now.getHours() - 3);  // GMT-3

let hh = now.getHours().toString().padStart(2, '0');
let mm = now.getMinutes().toString().padStart(2, '0');

msg.payload = JSON.stringify({
  current_time: `${hh}:${mm}`,
  on_time: "22:00",
  off_time: "23:00",
  led: false
}) + "\n";

return msg;

🧠 Source code

🛠️ Serial debugging

In the Serial Monitor, the device prints:

📥 Incoming JSON
⏰ Current time
⏱️ Scheduled range
💡 Relay status

🧪 Test cases

Scenario	Expected result
Time 21:00, on 20:00, off 22:00	💡 ON due to schedule ✅
Time 23:00, led: true	💤 OFF (schedule takes precedence)
Time 23:00, led: true + valid schedule	💡 ON (time wins) ✅

🔐 License

Part of the GrowHardware ecosystem – open, modular, and extendable. Fully compatible with AI-Core and future automation modules.