Teacher Cat Lamin has written up a quick sort-of review of the brilliant PiStop from 4tronix. This simple little GPIO plug in board gives you access to some traffic light LEDs that you then program using your favourite language on the Pi. Cat’s class have used ScratchGPIO and she’s blogged about how to do that as well as give her overall impressions of the device. Well worth reading if you want a cheap, simple way of getting into GPIO programming. Read it here. You can buy a PiStop from 4tronix.