It's very common for Arduino Uno users to run short of pins because there’s a lot of projects that requires more than 20 signal pins. The only option they are left with is buying an expensive Arduino Mega or any other microcontroller with more pins. This shield provides a cheap solution to this problem by adding 18 signal pins to Arduino Uno.
Arduino library associated with this shield makes it really easy to use the pins of this shield and perform basic input/output tasks. Download the Library & example sketches from the "Documents" section.
As there’s no multi-threading feature, your Arduino Uno alone cannot perform two or more tasks simultaneously. This shield can be a way around to this issue as using this shield with Arduino Uno is like using two Arduino boards together. Advanced users can use this feature by uploading their own program to the on-board atmega8 chip of this shield using Arduino Uno as ISP. To know more, have a look at the user manual from the "Documents" section.
Arduino Uno Alone
Arduino Uno + I/O Expansion Shield
No. of I/O Pins
• Communication method with arduino board: I2C.
• No. of additional pins: 18.
• 4 additional ADC pins and 3 additional PWM pins.
• Dedicated arduino library for this shield.
• On-board microcontroller can be reprogrammed easily using arduino as ISP.
• L-shaped header helps using this shield when other shields are connected on top of it.