1) Via I2C or SPI interface chips
One way of getting the Raspberry GPIO pins to read analog sensor inputs is via I2C or SPI interface chips such every bit the ones flora on the RasPiO Analog Zero board, ADC Pi Plus board, DFRobot 18-Bit ADC board and JeeLabs Analog Plug board, which are Analog to Digital converter boards that piece of job the MCP3008 and MCP3424 chips.
RasPiO Analog Zero board uses the MCP3008 chip as well as tin connect to whatsoever 40-pin Raspberry Pi, too every bit Raspberry Pi Zero as well as older 26-pin Raspberry Pi (with the assistance of a Downgrade GPIO Ribbon Cable)
Hooking upwards an RC circuit to the Raspberry Pi is unopen to other way to larn analog values from the Raspberry Pi yesteryear connecting analog sensors to 1 GPIO pivot of the Raspberry Pi. Then, you lot house a resistor as well as capacitor inwards series on a breadboard as well as connect the breakout wires to PIN1 (3.3V) as well as PIN6 (Ground) of the Raspberry Pi to practise an final result where the GPIO pivot goes from LOW to HIGH to register a reading. This is done yesteryear discharging the capacitor (by setting the GPIO pivot LOW every bit an output) as well as then, setting the GPIO pivot every bit inwards input to let the capacitor to accuse to at to the lowest degree ii volts thence the GPIO pivot volition register HIGH. Here is visually how the Resistor–Capacitor (RC) circuit method works:
3) Analog-to-Digital Converter Integrated Circuit
This tertiary way is similar to the RC charging circuit method above, simply it integrates an Analog to digital converter (ADC) chip inwards the circuit, allowing the Raspberry Pi to locomote able to read multiple analog signals. To practise an ADC integrated circuit that tin read multiple sensor inputs all you lot postulate is a breadboard, breadboard breakout wires, 10K ohm resistor as well as a 1uF capacitor, too every bit an Analogue-to-digital converter (ADC) similar the MCP3008 chip or similar chip that is pivot compatible as well as uses the SPI protocol for successful information communication betwixt the ADC as well as the Raspberry Pi.
4) Connecting Arduino to the Raspberry Pi
Another option to getting analog inputs from the Raspberry Pi would locomote to connect the Arduino to the Raspberry Pi every bit Arduino commonly has a 10-bit ADC on board. With an Arduino, you lot would locomote able to trigger as well as command inwards existent fourth dimension potentiometers as well as many other analog sensors via USB connectedness without having to programme inwards Arduino’s quasi-C++ language.
While it is bully you lot tin piece of job the features as well as benefits of the Arduino microcontroller, the drawback of using Arduino amongst your Raspberry Pi to perform analog sampling is that Arduino's series device hollo tin modify every fourth dimension you lot connect Arduino to your Raspberry Pi. This agency you lot volition bring to manually uncovering Arduino's device hollo every-time as well as connect via USB which tin larn annoying.
Constructing a uncomplicated RC circuit as well as ADC circuit is definitely fun though it requires setting upwards the Raspberry GPIO pins, installing the necessary software as well as executing Python code which volition expire to a greater extent than complex the to a greater extent than sensors you lot add. Of course, you lot could easily add together the sensors inwards Raspberry Pi Cayenne without having to practise whatsoever coding.
Still, if you lot practise non similar tinkering much amongst breadboard wires; amongst a solution similar the RasPiO Analog Zero board you lot tin easily command GPIO pins as well as read analog sensors amongst real few lines of code because the board is slowly to code amongst RPi.GPIO +Python and GPIO Zero +Raspberry Pi Python libraries so it requires minimal boilerplate code to larn started.