Crowbits-Voltage Sensor can measure the voltage in a circuit, which is very convenient for your design.
Using the principle of the partial voltage of resistance in series, two resistors connected in series with the positive and negative power, the resistance near the power supply is 30K, and the resistance near the ground is 10K, So the ratio of the up and down resistance is set to 1/4VCC, because the resistance is directly and at both ends of the power supply, so no matter how the power supply voltage changes, the intermediate voltage of the two resistors is always 1/4 of the power supply voltage, So just read the voltage value between the two resistors and multiply it by four, which is the actual voltage value of the supply voltage.
In the complete circuit, use the wire to lead out the part to be measured, connect the wire at both ends of the terminal of the module, download the corresponding program, and then you can detect the voltage.