Weather Buoy - ESP32 4G/LTE Solar

• On-water solar powered autonomous wind and weather station
• ESP32, SIM7600E, GILL MaxiMet GMX501

Electronics part list

Part	Description	Links	Cost (ex. delivery)
Waterproof housing	Fibox PCM200/100T, 255x180x100 Polycarbonat	Fibox 6016927, conrad	EUR 46
Weather station	Gill MaxiMet: ultrasonic windspeed/direction, compass, solar radiation	GILL MaxiMet GMX501 Note: GMX200 costs half, just lacks solar	EUR 1500-3000
Microcontroller	Lilygo ESP32	LILYGO® TTGO T-PCIE ESP32-WROVER-B	EUR 10
4G/LTE Modem	SimCom 7600	PCIE-SIM7600E Module	EUR 30
Solar panel	12V, 20W, monocrystalline, water proof IP65	Offgridtec	EUR 27
Solar charging controller 12V	LiFePo4 capable, 5V power for microcontroller	Victron Bluesolar, MPPT, 75/10	EUR 80
RS232 to TTL converter	MAX3232 to convert weatherstation's RS232 to 3.3V serial	Sparkfun MAX3232 tranceiver breakout	EUR 5
Voltage/Current sensor	MAX471 module, uses ESP32 ADC as there is no serial available to connect the ESP32 to the Victron Solar charger	MAX471 module with voltage divider, MAX471 datasheet	~EUR 2
Water Temperature sensor	DS18B20 cable	DS18B20 cable	~EUR 3
On-Board Temperature sensor	DS18B20 TSO module	DS18B20 TSO	~EUR 1
Battery	LiFePo4, 12V, 6Ah, 4S1P, including BMS	Jubatec	EUR 60
5V Power	convert ~14V Battery voltage to 5V for ESP32	TracoPower TSR 1-2450 DC/DC-Wandler, 24V/DC 5V/DC 1A 6W	EUR 6
M12 male front-mount	Solar panel power, 4-pins, 2 pins combined to double current of 4A per pin	7000-13501-9710050	EUR 10
M12 female with cable	Solar panel power, 4-pins, 2 pins combined to double current of 4A per pin, soldered to solar panel	7000-12221-6340200	EUR 10
M8 male connector	soldered to Water temperature sensor cable	7000-08401-0000000	EUR 11
M8 female front-mount 3-pin	Water temperature sensor	7000-08571-9700050	EUR 9
M12 female front-mount 5-pin	RS232 data and 5V power connection to Maximet weatherstation	7000-13561-9720100	EUR 12
M12 male connector cable 5-pin	RS232 data and 5V power connection to Maximet weatherstation with Maximet specific IP67 soldered Connector	7000-12041-6250300	EUR 11
Pressure compensation unit	Wiska EVPS - Pressure compensation unit, VentPLUG, plastic, metric	WISKA EVPS 40 10106593	EUR 4

wiring

wiring diagrams

CAD: 3D-print & PCB

files are in the folder /cad

System: Fusion 360 live model PCB: Fusion 360 live model

how to order a PCB:

• choose a PCB manufacturer. recommendation: https://www.eurocircuits.com/
• upload weatherbuoy pcb.brd to e.g. eurocircuits to order your PCB

firmware

• built with ESP-IDF Version 4.3 or later
• adds software components for
  • Cellular handling for SimCom 7600E Modem
  • Max417 current/voltage measurement
  • Comfortable/safer Strings
  • reading/parsing Gill Maximet data from serial interface
• new as of February 2022:
  • remotely configuring Gill Maximet wind/weather stations
  • NMEA2000 data output for a real-time Display e.g. Garmin GNX130
  • SMS and Buzzer alerting based on GPS geofence, tilt sensor, and Maximet unplugging
  • Use exactly same electronics also to simulate a maximet station for testing purposes
  • upgraded to ESP-IDF 4.4
  • improved serial/UART handling to maximet and modem for performance and robustness

Lilygo TTGP T-PCIE SIM7600E PIN usage

• UART0: RX: GPIO3, TX: GPIO1 (USB, logging, debugging)
• UART1: RX: GPI13, TX: GPIO14 (Maximet RS232)
• UART2: RX: GPIO16, TX: GPIO17 (SimCom Modem)
• ADC: GPIO39 (Max471, Voltage)
• ADC: GPIO34 (Max471, Current)
• TWAI: RX: GPIO22, TX: GPIO21 (I2C ports for driving NMEA2000 display)
• OUT: GPIO19 (Buzzer, up to max 70mA)

SIM7600E modem firmware

• LE11B03SIM7600M21-A v1.12 B03 cannot be switched to LTE (works only as GSM modem)

• LE11B04SIM7600M21-A v1.12 B04 works fine also in LTE mode

• LE20B04SIM7600M21-A v2.0 B04 works find also in LTE mode

  Lilygo Firmware upgrade instructions https://github.com/Xinyuan-LilyGO/LilyGo-T-PCIE/blob/master/doc/sim7600SA_update_firmware.md

troubleshooting

cannot flash via serial/USB anymore

• remove serial connection to Maximet (or turn off/reset Maximet/Simulator device) https://esp32.com/viewtopic.php?t=1205

observing weird crashes, especially after changing git branches

• completely delete the build folder and perform a 100% clean build https://esp32.com/viewtopic.php?t=1205