Pinout

GPS NEO-6M module (GY-NEO6MV2) pinout

Pins

VCC (3.3–5V — most GY-NEO6MV2 boards carry a 3.3V regulator)
RX (module input — connect to the MCU TX)
TX (NMEA sentences out, 9600 baud default)
GND
The PPS LED blinks once per second only after a satellite fix — first fix outdoors can take minutes

Receiver	u-blox NEO-6M
Signal	GPS L1, 1575.42 MHz
Channels	50
Supply (breakout)	3.3–5 V (onboard 3.3 V regulator)
Logic level	3.3 V
Interface	UART, 9600 baud default, NMEA output
Update rate	1 Hz default (up to 5 Hz)
Position accuracy	2.5 m CEP
Time to first fix	≈ 27 s cold start, ≈ 1 s hot start
Sensitivity	−161 dBm tracking
Antenna	25 × 25 mm ceramic patch, u.FL

HC-05 / HC-06 Bluetooth serial module (ZS-040)Bluetooth: v2.0 + EDR, Classic SPP (no BLE); Role: HC-05 master/slave; HC-06 slave only; Frequency: 2.4 GHz
NRF24L01 2.4GHz radio (2×4 header)Chip: Nordic nRF24L01+; Supply voltage: 1.9–3.6 V (use 3.3 V); Logic inputs: 5 V tolerant
RFID-RC522 reader (SPI)Chip: NXP MFRC522; Frequency: 13.56 MHz; Supported cards: ISO/IEC 14443 A, MIFARE Classic/Ultralight
LoRa module (RFM95W / SX1276-family)Transceiver: Semtech SX1276 (RFM95W); Frequency: 868 / 915 MHz (RFM95W); 433 MHz on RFM96/98W; Supply voltage: 1.8–3.7 V (no onboard regulator)
SIM800L GSM moduleNetwork: 2G only: GSM/GPRS quad-band 850/900/1800/1900 MHz; Supply voltage: 3.4–4.4 V (≈ 4.0 V ideal, not 5 V); Peak current: Up to 2 A transmit bursts
CP2102 / CH340 USB-to-serial adapter (6-pin)Chip: Silicon Labs CP2102 or WCH CH340; USB: USB 2.0 full speed (12 Mbit/s); Baud rate: CP2102: 300 bps–1 Mbps; CH340: 50 bps–2 Mbps
MAX485 RS-485 transceiver module (8-pin breakout board)Transceiver: MAX485; Supply voltage: 5 V (4.75–5.25 V); Logic level: 5 V (use MAX3485/SP3485 for 3.3 V)
CAN bus transceiver module (MCP2515 + TJA1050)Controller: Microchip MCP2515 (CAN 2.0B); Transceiver: NXP TJA1050; Supply voltage: 5 V (TJA1050 is 5 V only)