Comparisons

Arduino-compatible wireless modules are available for many different communication needs. Some are meant for short-range Bluetooth connections. Some are designed for low-cost microcontroller-to-microcontroller links. Others are made for long-range, low-data-rate communication. This article compares four common wireless module types: nRF24L01, HC-05, JDY-16 and LoRa modules. They are all useful, but they solve very different problems. […]

Microcontrollers often run out of input and output pins. This is especially common when a project uses buttons, relays, LEDs, keypads, displays or several modules at the same time. I2C GPIO expanders solve this problem by adding extra digital pins through the I2C bus. Two common I2C GPIO expanders are the MCP23017 and the PCF8574.

The HC-05 and JDY-16 are both small Bluetooth modules often used with Arduino-compatible boards. At first glance, they seem similar because both can connect to a microcontroller through a UART serial interface. In practice, they are based on different Bluetooth technologies and are used in different types of projects. The HC-05 is a Bluetooth Classic

I2C modules make it easy to connect sensors, displays, RTCs, ADCs, DACs and other devices with only two signal wires. But as projects grow, two common problems appear: too many I2C devices with the same address, or not enough digital input/output pins. An I2C multiplexer and a GPIO expander both help expand a microcontroller project,

The nRF24L01 is a popular low-cost 2.4 GHz radio transceiver module for Arduino-compatible projects. It is commonly available in two very different hardware styles: the small PCB antenna module and the larger version with PA+LNA and an external antenna connector. Both versions use the same basic nRF24L01 radio family, but they behave very differently in

Logic level converters are used when one part of a project uses 5V logic and another part uses 3.3V logic. This is common when connecting older Arduino UNO-style boards to modern sensors, displays, ESP32 modules, RP2040 boards or XIAO modules. Two common level-shifting approaches are BSS138 MOSFET-based bidirectional level shifters and TXS0108E automatic bidirectional level

The Arduino UNO, Arduino Nano and Arduino Pro Mini are three of the most common ATmega328P-based development boards. They are closely related because they use the same basic microcontroller, but they are very different in size, connectors, power handling and practical use. This comparison helps explain when to use a full-size UNO-style board, when a

Low-cost wireless modules are popular for Arduino-compatible projects because they make it possible to send data without cables. However, simple 315/433/868 MHz RF modules, nRF24L01 modules and LoRa modules are very different technologies. They do not offer the same range, reliability, data rate or software complexity. This article compares simple RF transmitter/receiver modules, nRF24L01 modules

Many Arduino-compatible projects mix older 5V boards with newer 3.3V modules. A classic Arduino UNO or Nano usually uses 5V logic. Many modern boards, sensors and wireless modules use 3.3V logic. This difference matters because signal voltage is not only a power supply detail. It can decide whether a circuit works reliably or whether a