Firmware

The firmware (fw/main.ino) is an Arduino sketch compiled and flashed to the ESP8266 microcontroller. It initializes both temperature sensors and implements a simple command-response protocol over serial.

Board and toolchain: - Board: ESP8266 (NodeMCU, Wemos D1, or equivalent) - Arduino IDE: Configure board as "NodeMCU 1.0 (ESP-12E Module)" or equivalent ESP8266 variant - Baud rate: 115200 (8N1)

Required libraries (install via Arduino IDE Library Manager): - Adafruit MAX31865 – Adafruit's MAX31865 RTD converter library - DallasTemperature – OneWire temperature sensor library - OneWire – OneWire protocol library (usually bundled with DallasTemperature)

Flashing: 1. Connect the ESP8266 board via USB-to-Serial converter (TX → RX, RX → TX, GND → GND, 3.3V → 3.3V) 2. Select board type and COM port in Arduino IDE 3. Open fw/main.ino and click Upload 4. Monitor serial output at 115200 baud to confirm "ESP8266 is ready" and "Dallas sensor is ready"

Protocol and commands:

The device listens for ASCII commands on serial. Commands are case-sensitive and must be terminated with a newline or carriage return (or neither—the firmware processes them immediately upon completion).

Command	Response	Description
R	<clock>,<plate>,<ambient>	Request timestamped temperatures. clock is milliseconds since boot. plate is PT100 temperature (°C, 2 decimals) from MAX31865. ambient is DS18B20 temperature (°C, 1 decimal) from OneWire.
*IDN?	ROSATECH,TSN100,P0000002,1.0.1	Request device identification: manufacturer, model, serial number, firmware version.

Example serial session (115200 baud):

R
12345,23.45,22.1
R
12455,23.47,22.1
*IDN?
ROSATECH,TSN100,P0000002,1.0.1

Key firmware details: - MAX31865 configuration: 2-wire mode, RTD nominal resistance 100 Ω (PT100), reference resistor 430 Ω - Timestamp source: millis() wraps every ~49 days - Sensor reading timing: DS18B20 is sampled after MAX31865; there is no inter-sample delay between the two readings - Buffer handling: Commands are accumulated character-by-character and processed when the full command string is matched; newlines and carriage returns are ignored