There is no better way to learn electronics than building your own toys with Arduino and Raspberry Pi. 1Sheeld+ is a multi-purpose Arduino shield that lets you use your smartphone to interact with your RC car or other toys. It can be used as input or output for Arduino, speeding up the prototyping process.
1Sheeld+ lets you experience over 40 Arduino shields on your iPhone and Android device. It is compatible with Uno, Mega, Due, and other Arduino boards. You get text to speech, voice recognition, data logger, Internet, SMS, and social media, and many shields to try.[where to find more info]