Looking to pair Arduino with mobile devices? Here are some notes from my Free Range Arduino presentation at FITC‘s Screens 2013.
Smartphones come bundled with powerful technology. Rather than buy and integrate sensors and communications, we can leverage the sensors already built into smartphones (Magnetometer, Accelerometer, Touchscreen, speakers, microphones etc.) and simultaneously augment our phones and the Arduino board. Bonus: we can use SMS and other amazing tech with our inexpensive buttons, switches and other triggers.
Bridging with a PC – many devices
Any phone browser that has websocket capabilities can be used to drive an Arduino. There are many ways this can be done but usually the structure involves an Arduino physically connected to a server and multiple web clients sending/ receiving data from that server. nodejs and noduino or node-arduino are great combos for this. Breakout.js is also very useful.
If you’re lucky, Breakoutjs requires very little to setup; it consists of a Java server that needs to be run and a firmata sketch that needs to be uploaded to the Arduino. The “getting started” example on the Breakoutjs site is helpful, but neglects to mention that you need to navigate to a test directory to try things out. For example, http://192.168.0.20:8887/examples/getting_started/blink_led.html
Mega ADK – Android devices
The Arduino Mega ADK lets us plug an Arduino board directly into an android device over an USB connection (e.g. type-a to the micro-b connector on many devices). Once connected, a custom application must be built to communicate between the android device and the Mega ADK. Probably, the easiest starting point for making an Android/ Arduino friendly application is the ADT (Android Developer Tools ide). However, documentation is generally poor and non-specific.
Bluetooth – Android devices
Using a Bluetooth Arduino module, like the Bluesmirf, you can connect directly to to your phone and communicate via an app. When used in conjunction with the powerful Amarino Toolkit you don’t really have to do much at all.
- Install the Amarino apk on your Android device – available at the Amarino downloads page
- Upload a sketch to your Arduino that responds to Serial data. Here’s my sketch.
- Setup a bluesmirf and your Arduino board
- Open Amarino and connect to your bluesmirf
- Send messages to your board
Custom iOS cables – iOS Devices
Using the Redpark TTL Serial Cable, you can connect directly between a custom iOS application on your iOS device and your Arduino. Sadly, Apple requires special licensing for hardware enabled applications which will stop you from submitting your Arduino prototype to the App Store, but you can still upload directly to your device as long as you have the proper certification.
- Connect the Redpark TTL Serial Cable to your Arduino board – you only need to connect the ground pins, Arduino rx to tx on the cable and Arduino tx to rx on the cable
- Upload the Paduino friendly sketch to your board
- Connect the Arduino to your iOS device
- Open paduino
Custom FSK cable – whatever
This is my fav. technique. You use a TTRS audio connector (stereo and microphone audio) and the headphone jack on your device to send beeps back and forth between your Arduino and a custom application. This is the technique by which older modems operate. Frequency-shift keying involves modulating and demodulating (where we get the word ‘modem’ from) a signal so that it can be used to transmit data. An excellent introduction to FSK and Arduino.