The first android app I’m looking at allows you to experiment with the GPIO header on your raspberry pi.
GPIO Tool For Raspberry Pi
The app supports the Quick2Wire Interface, IO Expander and Analog Boards. Adafruit LCD Plate, PiFace Command and Display. DS18B20 Temperature Sensors.
DHT11 Humidity Sensor and BMP085.
The temperature sensors are graphed, and can be displayed on an LCD display.
Uses a utility which it will install on the RPi, to communicate to your android, allowing switching of the pin modes, from input(pull high/pull low) to output & PWM. When pin set to output it will allow setting to high/low, for input pins will show current input state of high or low.
The RPi is communicated using SSH, to install the utility the ssh user will have to have non-password sudo access.
The app is ad supported but you there is an in-app purchase to remove the ads
Permissions
Link
GPIO Tool For Raspberry Pi on Google play
