- No leds
- only 5-bit Digital to Analog converter (DAC) with 0..5V output (GB has 8 or 10 bit)
- only four relay connections (GB has 6)
+ Realtime clock
+ barrel connector for power jack
+ Four PWM outputs (GB has 1 on port 18)
+ IR Remote Control input
+ Arduino Shield connectors
+ Power supply (Not needed with GB)
The ATMEGA328P uses 5V signal level, whereas on the GertBoard it's running at 3V3.
I don't know whether this board has buffers on the GPIO connections (GertBoard does).
It looks more "Arduinoey" than the Gertboard. That may be a good thing for some and a bad thing for others.
The board is designed as versatile, general-purpose data acquisition and control module and provides a direct connection to Raspberry Pi GPIO connector (26 pins).
Whereas the Gertboard is designed to teach people about computer interfacing.