A simple system for sensor & controls at home

A lot of home tinkering would be easier if there were ready made units that you could link together either wirelessly or via USB. Maybe this already exists in some way, shape or form but it is not obvious to me where and at what price in that case.

It seems to be that for home tinkerers working wth with Arduionos ESP8266s and Raspberry Pis, there should be room for a whole lot of compartmentalization.

Gui and communications unit

Should be Android phones and tablets. There is no way it is cheaper and more convenient to cobble together a touch screen, batteries, USB/Wifi/Bluetooth/3G/4G/LE connectivity and charging circuits than simply using an Android device. Many nowadays even have wireless charging.

Power control unit.

Controlled over e.g. USB. Switches on and off mains power, and guaranteed to do so in sequence between different connectors, in case you want to mimic a rotary switch. There is a USB controlled multi channel relay on Amazon, but it seems to close all circuits on boot, which can be anything from annoying to catastrophic depending on your project Amazon.com: SainSmart USB Eight Channel Relay Board for Automation - 12 V: Industrial & Scientific.

From one of the reviews:

I think the biggest issue is that way the thing reacts to rebooting the machine it is connected to. I haven't figured out the exact sequence, but I think it turns on all relays when the computer/usb reboots, and then again when the driver loads

So at the moment it may be a better idea to put together a device from either a Raspberry Pi or an Arduino, and then connect that to a relay board and mount it all in a case.

Network interface unit.

Connects to the power control unit. Could be bluetooth, bluetooth LE, WiFi, 3G/4G/LE or something.

Sensors

Sensor, powered locally by AA, AAA or button cell. Reports its readings wirelessly. Texas Instruments seem to have a candidate  SimpleLink™ Bluetooth Smart®/Multi-Standard SensorTag - CC2650STK - TI Tool Folder.

10 sensors including support for light, digital microphone, magnetic sensor, humidity, pressure, accelerometer, gyroscope, magnetometer, object temperature, and ambient temperature