Cellular-Enabled IoT Device with Real-Time Clock and Power Management
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Circuit Documentation
Summary
This circuit integrates various components to perform a set of functions centered around the LilyGo-SIM7000G module, which appears to be the main microcontroller unit with cellular connectivity capabilities. The circuit includes power management components such as a buck converter and a DC power source, as well as a real-time clock (RTC DS3231), an 8-channel opto-coupler for isolating different parts of the circuit, voltage sensors, a fuse for protection, a rocker switch for power control, and an LED indicator. The circuit is powered by 12V batteries.
Component List
LilyGo-SIM7000G
- A microcontroller module with cellular connectivity.
- Pins: 3V3, GND, 32, 33, 34, 35, 25, 26, 27, 04, 02, 15, 14, 13, 12, VBAT, VIN, RST, 0, 36, 39, 05, 18, 19, 23, 21, 22, RXD, TXD
8-Channel OPTO-COUPLER
- An opto-coupler module used for isolating different parts of the circuit.
- Pins: COM GND, IN8, IN7, IN6, IN5, IN4, IN3, IN2, IN1, GND, VCC, OP1, OP2, OP3, OP4, OP5, OP6, OP7, OP8
Buck Converter
- A power converter that steps down voltage from a higher level to a lower level.
- Pins: IN+, IN-, OUT+, OUT-
DC Power Source
- Provides the power supply for the circuit.
- Pins: Ground, Positive
Fuse
- A safety device that protects the circuit from overcurrent.
- Pins: Terminal 1, Terminal 2
Rocker Switch
- A switch to control the power supply to the circuit.
- Pins: 1, 2
RTC DS3231
- A real-time clock module for keeping track of time.
- Pins: 32K, SQW, SCL, SDA, VCC, GND
Terminal PCB 2 Pin
- A simple two-pin terminal for connecting external devices.
- Pins: Pin A, Pin B
Voltage Sensor DC
- A sensor for measuring DC voltage in the circuit.
- Pins: signal, vcc, gnd, GND, VCC
12v5ah Battery
- A 12V battery providing power to the circuit.
- Pins: 12v +, 12v -
LED: Two Pin (green)
- An LED indicator.
- Pins: cathode, anode
Wiring Details
LilyGo-SIM7000G
- 3V3 connected to RTC DS3231 VCC
- GND connected to LED (green) cathode, RTC DS3231 GND, Buck Converter OUT-, 8-Channel OPTO-COUPLER COM GND and GND
- 32 connected to Terminal PCB 2 Pin Pin A
- 33 connected to 8-Channel OPTO-COUPLER OP5
- 34 connected to Voltage Sensor DC signal
- 25 connected to 8-Channel OPTO-COUPLER OP2
- 12 connected to LED (green) anode
- VIN connected to Rocker Switch pin 2
- 36 connected to Voltage Sensor DC signal
- 39 connected to 8-Channel OPTO-COUPLER OP1
- 19 connected to 8-Channel OPTO-COUPLER OP3
- 23 connected to 8-Channel OPTO-COUPLER OP4
- 21 connected to RTC DS3231 SDA
- 22 connected to RTC DS3231 SCL
8-Channel OPTO-COUPLER
- VCC connected to LilyGo-SIM7000G 3V3
- OP5 connected to LilyGo-SIM7000G 33
- OP2 connected to LilyGo-SIM7000G 25
- OP1 connected to LilyGo-SIM7000G 39
- OP3 connected to LilyGo-SIM7000G 19
- OP4 connected to LilyGo-SIM7000G 23
- IN5 connected to Terminal PCB 2 Pin Pin B
- IN4 connected to terminalblock-04-01 pin 7
- IN3 connected to terminalblock-04-01 pin 5
- IN2 connected to terminalblock-04-01 pin 3
- IN1 connected to terminalblock-04-01 pin 1
Buck Converter
- IN+ connected to Fuse Terminal 2
- IN- connected to DC Power Source Ground
- OUT+ connected to Rocker Switch pin 1
- OUT- connected to LilyGo-SIM7000G GND
DC Power Source
- Ground connected to Buck Converter IN-
- Positive connected to Fuse Terminal 1
Fuse
- Terminal 1 connected to DC Power Source Positive
- Terminal 2 connected to Buck Converter IN+
Rocker Switch
- Pin 1 connected to Buck Converter OUT+
- Pin 2 connected to LilyGo-SIM7000G VIN
RTC DS3231
- VCC connected to LilyGo-SIM7000G 3V3
- GND connected to LilyGo-SIM7000G GND
- SDA connected to LilyGo-SIM7000G 21
- SCL connected to LilyGo-SIM7000G 22
Voltage Sensor DC
- VCC connected to 12v5ah Battery 12v +
- GND connected to 12v5ah Battery 12v -
- Signal connected to LilyGo-SIM7000G 34
12v5ah Battery
- 12v + connected to Voltage Sensor DC VCC
- 12v - connected to Voltage Sensor DC GND
LED: Two Pin (green)
- Anode connected to LilyGo-SIM7000G 12
- Cathode connected to LilyGo-SIM7000G GND
Code Documentation
No code has been provided for the microcontrollers in the circuit. If code is later provided, it should be documented here with explanations of the functions, setup, and main loop, along with any interrupt service routines or additional functions.