Quick Guides

The guides in this section are an easy reference to all the boards, communication modules, sensors, relays, and actuators that you will use in projects.

They provide the following important details:

• Supply and Operating Voltage

Microcontroller boards need a supply voltage to power them on, and this is usually 5V. They have output voltage pins to supply power to connected components, which can be 5V or 3.3V or both. The operating voltage of a board is the voltage of the signal ouput on the pins to which components and other boards are connected to exchange data with.

Modules and components almost always have the same supply and operating voltage.

It is very important to know the operating voltage of the board and each connected component. If a component with a 3.3V operating voltage is connected to a board with a 5V operating voltage the component may burn out. If a component with a 5V operating voltage is connected to a board with a 3.3V operating voltage it may not work properly.

For example, an Arduino Nano can supply 5V or 3.3V to power components but has an operating voltage of 5V. So even if you connect a 3.3V with the correct supply voltage it may still burn out because the signals from the Nano will be at 5V.

On the other hand an ESP32 can only supply 3.3V and has the same operating voltage. So all 3.3V components will work just fine but 5V components may need an alternative power supply, while the signal voltage may be sufficient.

• Current Drawn

Each microcontroller board is capable of supplying a maximum current and each connected component draws a certain amount of current. If the connected components together draw more current that the microcontroller board can supply the circuit may not work properly.

• Communication Protocol

All components exchange data with the Microcontroller board using one of three communication protocols (UART, SPI, or I2C) which can be understood by the pins on the component. Microcontroller boards have limited pins for each protocol so if multiple components using the same protocol have to be connected there may be some code changes required.

UART communication requires two dedicated pins per component, but almost all pins on a microcontroller board can be used for UART communication with the required code changes.

I2C communication requires two specific pins (SDA and SCL). But each I2C component is programmed with a specific address so multiple components can be managed with the same set of microcontroller board pins as long as they have different addresses.

SPI communication requires four specific pins (COPI, CIPO, CS, and SCK). While mulitple SPI components can be connected to the same set of microcontroller board pins some code is required to select the component to exchange data with.