How do you link your microcontroller to sensors and actuators?

Chose Suitable MCU Use appropriate interfaces like I2C, SPI, or UART for sensor communication. Interface GPIO pins or specialized interfaces to link actuators. Write code to interact with sensors, collecting data through established connections. Control actuators by sending signals through specified output pins. Ensure compatibility and proper voltage levels for seamless integration Test application to demon stare

One thing I've found very helpful is to use Digital and/or Analog interface. Thanks the best way to start using and with a simply multimeter it's easy to see and understand with short and simple programs. Also it applies for any microcontroller family (Arduino, Microchip PICs, Espressif ESP32 or ESP8266, etc). One you obtain experience and better undertanding how devices works, then some communication interfaces are useful, i.e. I2C for LCD displays or sensors, a serial link (RS485/RS232) for serial devices or industrial PCs and wireless protocols for some more advance hardware. It also depends on the application you are working on: I2C has the advantage of easy hardware scalabilty using only 2 wires for the bus to add new sensors/actuators

There are few suggestions from my end - Select appropriate controller as per requirements - Consider power requirements in case of battery based product - Choose appropriate communication interface like I2C Or SPI or UART or others as per requirements - Choose appropriate network RF protocol as per IoT product requirements - Product or Project budget is also key point to choose controller and sensors as per requirements

Serial communication methods are also very effective in this case, i.e. the connection of the microcontroller with the sensors, for example, ONEWIRE, I2C, many sensors have the ability to communicate with the help of serial methods.

To connect the Microcontroller to a sensor or actuator, first, you need to know the output from the sensor or the actuator to decide the way of communication. The Analog communication (I/O) will be with analogue devices like potentiometers or PWM motors. The Digital will be best for ON/OFF control and state. And of course, serial communication which is digital communication will be the best with 3rd part communication chips like Bluetooth modules or SD card memory readers.

I2C (Inter-Integrated Circuit) is a multi-master, multi-slave, packet-switched serial communication protocol. It's suitable for short-distance communication and supports multiple devices on the same bus. Use Case: Accelerometers, gyroscopes, temperature sensors. SPI (Serial Peripheral Interface) is a synchronous serial communication protocol that uses multiple wires (MISO, MOSI, SCK, CS). It's high-speed and suitable for short distances. Use Case: Digital-to-analog converters (DAC). UART (Universal Asynchronous Receiver/Transmitter) is a serial communication protocol with separate lines for transmitting and receiving data. It's asynchronous and widely used for serial communication. Use Case: GPS modules, RFID readers, Bluetooth modules.

Not to forget, I3C is an evolutionary serial communication protocol that builds upon the legacy of I2C. It offers faster data rates and is designed for improved power efficiency. I3C supports multi-master, multi-slave configurations and introduces in-band interrupts and dynamic addressing. Due to its in-band interrupt capability and higher data rate, it can significantly reduce overall wiring, as many devices can be combined on the same bus. It's backward compatible with I2C and combines the simplicity of I2C with the high-speed capabilities of SPI.

To extend on the I2C, SPI and UART list of communication protocol, I think we should add I3C for the latest generation of devices. Not widely used yet but an option nonetheless. That being said, for most use cases, I2C is good enough for any inter board device control.

Remember that UART, SPI and I2C are all unbalanced digital communications methods. SPI and I2C are really meant for intra-PCB communications. If you try to use these over a long cable, you are likely to encounter bit errors. Use CAN, RS-485, or RS-422 as more robust protocols in a design involving cabling at long distances. I would use SPI only in an intra-PCB or stacked PCB configuration. I2C and UART are typically operated at much lower speed, so cabled connections might work between two PCBs connected by a cable within a device.* *Every situation is different, e.g. shielded vs. unshielded cable, enclosure construction...

Zigbee is often used in home automation, industrial control, and mesh networks. ? Range: Typically 10-100 meters. ? Examples: Xbee, CC2530. RF (Radio Frequency) Modules: General-purpose wireless communication for remote controls or data transmission. ? Range: Varies widely based on frequency and power, typically from a few meters to a couple of kilometers. ? Examples: NRF24L01, 433MHz RF modules. GSM/3G/4G/5G: Connect microcontrollers to the cellular network, allowing for SMS, voice, and internet connectivity. ? Range: As long as there’s cellular network coverage.

The sensors and actuators libraries are always a good way (Good practice) to minimize the time and cost to market, plus it provide a Hardware Abstraction Layer (HAL) to your program and application which is really recommended for scalability and portability of the code.

"In the company where I worked, we used a clever trick involving a T circuit (Resistor - Capacitor- Resistor) to detect three different states: GND, VCC, and an open circuit. The method involved changing the I/O PIN to an output, applying a low or high pulse, and after a few milliseconds, switching the I/O back to input mode to read the resulting value. This sequence could generate different states that indicated the 'three state' of the input."

It really depends on the application. Short distance reading with minimal data; I2C, I3C, SPI are excellent choices, SPI adds a bit of hw overhead but still it's great. However, if the sensors are far from the cpu in a noisy environment, differential signaling like CAN becomes the obvious choice. If the sensors have ethernet capabilities, ethernet/IP packets are also a very viable choice, f.ex MODBUS, where the bandwidth is exponentially larger when compared to the more primitive options.