There are a lot of potential projects you could tackle that would be benefit from an Arduino keyboard input. Unfortunately, full keyboards are difficult to find; most on the market are just numerical keypads. You could always connect your Arduino to a computer and send characters over the serial connection, but that defeats the purpose of using a small, low-cost, energy-efficient microcontroller development board. That’s why Electronoobs has designed this serial keyboard that you can use with an Arduino.
This is a full 40-button keyboard, complete with a shift key for entering special characters. There are also additional buttons for return, “OK,” and send — with one more unlabeled button that you can use for whatever you like. Those forty buttons are setup in a 4 x 10 matrix, so only 14 digital input/output pins are required. A Microchip Technology ATmega328P microcontroller, like what powers an Arduino Uno, is used to monitor the keyboard matrix. In turn, it outputs the characters over a standard serial connection. That connection only requires two wires, and operates at a 115200 baud rate by default.
The advantage of this keyboard is that it can be plugged directly into an Arduino, or just about any other microcontroller development board or device with a serial connection. To build it, you’ll just need to have the custom PCB manufactured and purchase the ATmega328P microcontroller, a 16MHz crystal, the buttons, and a few common components like resistors. This does require SMD (Surface Mount Device) soldering, so it’s not for beginners. But it’s perfect for adding a keyboard to your Arduino projects, and Electronoobs may sell these keyboards if there is enough interest.