Sensor network with Android

system

Background and motivation

Once I used RasPi/Arduino for IoT prototyping, ending up with unsatisfying results: complicated physical wiring problems.

So I started thinking of a combination of PIC16F1-based sensor network and Android to simplify physical wiring.

Architecture

This is a framework for developing IoT applications on Android supporting dynamic feature enhancements:

architecture

(Physical) sensor network and sensor blocks with plug&play protocol
CLI and FTDI device driver (and BLE device driver to be supported in the future)
Edge computing components plug-in
Flow-based programming (to be supported in the future)

CLI is also positioned as a main UI to launch other activities (plug-in etc).

Sensor network simulator is provided for debugging applications on Android w/o a physical sensor network.

I use EventBus to support messaging among components within the application on Android.

Sensor list

My smartphone is equipped with built-in sensors. I add a sensor network to my smart phone to add other sensors.

Sensor	Built-in	Add-on
Three-axis Accelerometer	Y	Y
Speed (hall sensor)	N	Y
Orientation sensor	Y	N
Magnetic sensor	Y	N
Temperature	N	Y
Humidity	N	Y
GPS	Y	N

Swapping Plug-in

At the moment, modify strings.xml manually to replace the current plug-in with another one:

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <!-- Edge computing plug-in -->
    <!-- Cycling -->
    <string name="edge_computing_plugin">jp.araobp.iot.edge_computing.plugin.cycling.Cycling</string>
    <string name="edge_computing_plugin_activity">jp.araobp.iot.edge_computing.plugin.cycling.CyclingActivity</string>
    <string name="edge_computing_plugin_button_name">Cycling</string>
    <!-- Template
    <string name="edge_computing_plugin">jp.araobp.iot.edge_computing.plugin.template.Template</string>
    <string name="edge_computing_plugin_activity">jp.araobp.iot.edge_computing.plugin.template.TemplateActivity</string>
    <string name="edge_computing_plugin_button_name">Template</string>
    -->

</resources>

In the future, I will add a more dynamic way to swap plug-in.

Enabling built-in sensors

Again, modify strings.xml manually to enable/disable built-in sensors:

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <!-- Built-in sensors -->
    <string name="enable_ambient_temperature">true</string>
    <string name="enable_relative_humidity">true</string>
    <string name="enable_accelerometer">false</string>

</resources>

Android apps

Use case: bicycle

I develop in-bicycle network using the output from sensor-network. It is like a cheap version of CANopen :-)

CLI Activity

screenshot_cli

Cycling Activity

screenshot_cycling

Technical requirements

Very low power consumption
Cheap
Show current speed, acceleration, temperature and humidity on a character LCD
Save time-series data (speed, temperature, humidity, acceleration and location) onto Android smartphone

Thing: my bicycle

network

Development tools

Programing language

Kotlin

IDE

Libraries

How to debug it

Since smartphone's USB port is occupied, connect adb to the smartphone via WiFi following the guide:

1. adb tcpip 5555
2. disconnect USB cable
3. adb connect <ip address of smartphone>:5555
4. adb logcat

Or use the sensor network simulator included in this repo screen shot

araobp / sensor-network-android

readme