The PCF8591 is a monolithically integrated, individually powered, low power, 8-bit CMOS data acquisition device. The PCF8591 has four analog inputs, one analog output, and one serial I2C bus interface. The three address pins A0, A1 and A2 of the PCF8591 can be used for hardware address programming, allowing access to eight PCF8591 devices on the same I2C bus without additional hardware. The address, control, and data signals for the inputs and outputs on the PCF8591 device are transmitted serially over a two-wire bidirectional I2C bus. Features: The module chip uses PCF8951. Supports external 4-channel voltage input acquisition (voltage input range 0-5v). Integrates the photoresistor, which can collect the ambient light intensity accurate value through AD. Integrates the thermistor, which can collect the accurate temperature of the ambient temperature through AD. Integrates 1 channel 0-5V voltage input acquisition (adjust the input voltage through the blue potentiometer). With a power indicator (the indicator will light when the module is powered). The module has DA output indicator. When the output voltage of the module DA output reaches a certain value, the DA output indicator on the board will be illuminated. The higher the voltage, the more obvious the brightness of the indicator. Standard double-panel, board thickness 1.6mm, beautiful layout, with through holes around, aperture: 3mm, convenient to fix. Specification: Single power supply PCF8591 operating voltage range of 2.5V-6V Low standby current Serial input/output via I2C bus PCF8591 is addressed by 3 hardware address pins The sampling rate of the PCF8591 is determined by the I2C bus rate. 4 analog inputs can be programmed as single-ended or differential inputs Automatic incremental channel selection PCF8591 analog voltage range from VSS to VDD PCF8591 built-in tracking and holding circuit 8-bit successive approximation A/D converter DAC gain is realized through 1 channel analog output Module PCB size: approx. 3.6 * 2.3 cm / 1.42 * 0.91 inch Package list: 1 * PCF8591 Module Module interface description The left and right sides of the module are respectively extended with 2 way pin interface, which are described as follows: Left AOUT chip DA output interface AINO chip analog input interface 0 AIN1 chip analog input interface 1 AIN2 chip analog input interface 2 AIN3 chip analog input interface 3 Right SCL IIC clock interface to the microcontroller IO port SDA IIC digital interface to the microcontroller IO port GND module grounded VCC power connector External 3.3v-5v Module red short-circuit cap instructions The module has three red short-circuit caps, which function as follows: P4 is connected to P4 short-circuit cap, select the thermistor access circuit P5 is connected to the P5 short-circuit cap, and the photoresistor is connected to the circuit P6 is connected to P6 short-circuit cap, select 0-5V adjustable voltage access circuit 1、The module chip uses PCF8951. 2、Supports external 4-channel voltage input acquisition (voltage input range 0-5v). 3、Integrates the photoresistor, which can collect the ambient light intensity accurate value through AD. 4、With a power indicator (the indicator will light when the module is powered). 5、The module has DA output indicator. When the output voltage of the module DA output reaches a certain value, the DA output indicator on the board will be illuminated. The higher the voltage, the more obvious the brightness of the indicator.