UDP Sender is a simple application to allow sending UDP packets either directly or, as I use it, by acting as a plugin for Tasker/Locale.
It is completely free, no ads are used. Please do rate/review it if you find it useful.
If you encounter any Issues please log them on Github (via https://github.com/hastarin/android-udpsender/issues) rather than giving poor reviews!
For apps not supporting the Tasker/Locale plugin format you can use an implicit Intent Intent.ACTION_SENDTO with a udp://host:port/data format URI to send packets.
I'm using it to control my lights from Limitless Led (http://www.limitlessled.com/ aka Mi-Light / Easybulb) via the Wi-Fi bridge and have included a couple of screenshots of the custom Tasker Scene I'm using. I use this scene along with gestures in my launcher to provide quick control of my lights.
Source code and more information, including the Tasker project shown, is available on Github: