A new update to the Soundboard application on Google Play has been released.
A new Tone Generation feature, which allows the user to generate sine-wave tones and play them back.
Also a bug fix - on the DTMF screen, swiping between the screens would effectively have the effect if the DTMF buttons being stuck in a pressed state, causing a continuous playing of the tone. The layout of that screen has been amended to reduce the occurrence of this happening.
From the app's start screen, use the Tone Generator button, or swipe across to access the tone generation module.
On that screen, use the slider or text box to select your chosen frequency, set the duration, and hit generate to play the tone
The module is also subject to the volume controls of the rest of the application - go to preferences in the menu and you'll be able to choose whether or not to dynamically set the volume level on playback, and set the volume level if you so wish.
As with all my apps, it is free, and as such, I am not in a position to offer any kind of official support, so use entirely at your own risk.
If you have any trouble with it, then feel free leave a comment or tweet and I'll try to help as and when I can, but I make no guarantees.