Air Waves is a "one to many" local radio broadcasting service which could be used for many things such as live translations for an audience, a baby monitor or a 2-way intercom/walkie-talkie.
Prior to creating this app, we had looked into alternatives. The translation system we were almost about to pay for cost nearly $8,000. That included only a transmitting station, microphones and 4 headset devices.
With Air Waves, we paid (in $AUD):
- wireless N150 router ($60)
- $120 for x2 cheap Android phones to test our setup with
- $20 for x2 in-ear Sony headphones
- $0 to bring your own additional listening device
So for $200 we've provided the same service which an $8,000 system would have, except Air Waves is easier to set up and far cheaper if we need more headsets.
*** How to use it ***
It doesn't get much simpler than this!
Click on the microphone to immediately start broadcasting.
Simply click on the headphone icon and choose the channel/language you want.
Note: all devices need to be on the same WiFi network.
*** Advanced usage ***
- Press menu to set your device name
- Press menu to enable/disable audio playback via headset (for speaker)
*** Hardware required ***
- At least 2 phones with Android 2.1+ installed.
- A router with wireless capabilities (preferably at least N standard)
- (optional) Some headphones and/or microphone for better audio quality
*** NOTES ***
I've been testing this at Ecclesia Mission Hills church (translation service) every Sunday for a few months and it's at the stage where I'm ready to release it into the wild to check for devices compatibility.
I've only tested on a handful of phones, simply because I can't afford to buy every phone in the market.
Below are the phones which are known to work with Air Waves:
- HTC Droid Incredible 2
- HTC One X
- Nexus 4
- Samsung i9000, S2, S III, Note II, S III Mini, S4 (SCH-I545 Verizon)
- Sony xperia X10 mini
- Xiaomi Mi 2S
- ZTE T12/Telstra Uno
Some additional advice:
- Note that both the broadcaster and audience must be on the SAME wireless network.
- There is notably less audio latency on Android +4.1 devices as Google has fixed up some audio processing issues.
- If you use a hands free microphone, the microphone you use will affect recording quality. Garbage in = garbage out
- Each broadcasting device has different methods of noise cancellation. Pick the one which works best for you.
- Each listener will use approximately 20Kbps, so please ensure your broadcasting device can handle the given number of listeners. See below for a detailed breakdown.
- Lite version can only broadcast for 2mins. You can get the full version here: https://play.google.com/store/apps/details?id=twig.nguyen.airwaves.pro
*** Wireless network speed ***
Theoretical vs actual and the number of supported listeners.
* Wireless G 54Mbps (actual 20Mbps) = 2,700 listeners
* Wireless N 150Mbps (actual 40Mbps) =
* Wireless N 300Mbps (actual 50Mbps) =
* Wireless AC 1300Mbps (actual 85Mbps) =
Formula: number of listeners = (actual Mbps * 1024) / 20Kbps
*** Currently working on ***
- random halts in receiving broadcast
- automatically reconnect to server
- use non-blocking IO
*** DISCLAIMER! ***
If you have any problems, EMAIL ME.
I'm still in the process of testing so please feel free to try it out and email me your feedback. I don't use reviews/comments as a form of "bug reports".
AirWaves is currently in testing. Please do NOT rely on Air Waves for something important.
*** Releases ***
- bumped required Android level to 2.2 (name change dialog breaks on 2.1, only used for internal testing)
- fixed crash on exit
- Initial release (testing for device compatibility)
- if broadcaster presses stop while listeners are connected, prompts speaker if they want to disconnect listeners
- fixed issue with listeners being unable to find broadcast when broadcaster locks screen
- added permission android.permission.WAKE_LOCK to prevent recording/wifi stopping when screen locked
- rewrote the broadcast into a service, no longer stops when switching to another app
- lots of code restructuring for future planned updates