Other Modules
Other modules — keypads, RFID reader, SD and micro SD card modules, joystick, W5500 Ethernet, optocoupler isolation, SPI flash memory and a 16-channel multiplexer. Modules that add input, storage and networking to a project.
Other Modules — buying guide
In the Other Modules category you’ll find various ready-made boards that add new functions to your main board: keypad, joystick, memory, network, RFID, isolation and pin-expander modules. To choose correctly, first decide what you want your board to do.
Which one to choose?
- Buttons and keypads: KY-004 is a single button, the large button module is a set of five. For entering numbers use the 4×4 keypad module or thin membrane keypads: 1×4, 4×4, 4×5.
- Joystick: KY-023 provides two analog axes and one button.
- Memory: The SD card module, Micro SD module and its simple version are for large amounts of data. W25Q32 is 4 MB of flash memory that stays on the board.
- Wired internet: The W5500 module and W5500 Shield connect the board to the router via Ethernet cable.
- Card-based access: The MFRC-522 13.56 MHz reader comes with a card and a key tag.
- Isolating circuits: The PC817 2-channel and 4-channel modules transfer the signal using light, keeping two circuits electrically isolated.
- When you run out of pins: CD74HC4067 connects 16 channels to a single common pin and uses 4 pins for selection.
Compatibility
- The SD card modules, W5500, W25Q32 and MFRC-522 work over SPI. These modules share the SCK, MOSI, MISO lines, and each one needs its own CS pin.
- MFRC-522 is powered from 3.3 V. Do not connect it to the 5 V pin.
- Format the SD card as FAT32 on a computer, otherwise the library might not detect it.
- A 4×4 keypad uses 8 pins. If you are short on pins, consider an I2C expander or another board.
Typical projects
- Door lock opened with a card: MFRC-522 and a relay.
- Data logger that writes sensor data to an SD card.
- Safe model that opens with a password.
- Robot controlled with a joystick.
Related categories
What is the difference between a membrane keypad and a button module?
The membrane keypad is thin, can be stuck onto an enclosure and fits into tight spaces. The button module is taller, but you can feel the click when you press it.
I’m out of analog pins on my Arduino – what can I do?
CD74HC4067 connects 16 sensors one by one to a single analog pin. Only one channel is read at any given moment, so it is not suitable for very fast signals.
