Audiorytmic Lantern

WARNINGS:

FIRST: If your Android device uses a XENON flash or similar technology that won't cope with repeatedly discharging in rapid succession, then you may burn your flash out. In any case, you are responsible for any hardware problem that may occur by using this Android App.

SECOND: The repeating bright light patterns may be harmful for epileptic people. This means that the exposure to the flash output from this application may eventually trigger an epileptic attack on anyone around you or yourself. Again, this is entirely under your own responsibility.

The audiorythmic lantern will listen into ambient sound through your Android device's microphone and brighten the screen (or the led FLASH on the back of your Android device) accoding to the sound level it registers. It is an attempt to get the effect of an accurate audiorythmic light.

You can place the phone or tablet near a speaker and watch it's effect for fun: The Android's screen will iluminate it's screen accordingly to the ambient sound level being perceived.

You can configure some aspects:

The light effect can be white light or colored light. On the colored light side, you can choose for RED, BLUE or GREEN channels. Also if this App detects that your Android device carries a LED FLASH (or any kind of flash) it will give you the option to use it for the audiorythmic effect.

You can also set up the sampling speed (in milliseconds). This parameter is configured at 100 ms by default, but you can shorten this value for better effects, provided you have a powerful Android device.

You can also leave dynamic levels at autosetting, or turn on manual tuning of minimum volume value, which is used to trigger the audiorythmic effect.

¿Why did I create this Android App ?

I searched for something similar in Google Play Store but could not find anything. This prompted me to develop such app by myself. I developed it at first only for my personal use. I use it on a tablet which has an HDMI output, which I hook into a DLP projector pointing at a mirror ball (disco ball). The result in my case is very good.

It is not an easy task, due to some rather external problems:

1) Processing power: Your Android device needs to have enough processor to do a decent sampling speed, which is 100 ms or less. >My phone starts going south at about 60 ms or less. Anyway, when the app starts skipping sampling frames, it just keeps the screen black, so the problem may not be too apparent.

2) Microphone quality and bias: Most phone's microphones are fine tuned into human voice, but then this app needs the whole sound spectrum to achieve the most realistic audiorythmic effect. On the other hand, Tablet's microphones are overall better for such task.

3) Algorithm vs hardware: My app tries to adjust itself to the lowest and highest volume, so it can get the correct usable volume frame, but some Android devices also include a hardware autodamp / autolevel for the microphone input, which competes with the app's algorithm. This is why you can turn off the auto limit for the lowest volume necessary to trigger the audiorythm effect.