Recently I brought this assembly kit Bluetooth led clock at Banggood:
Here are some pictures showing the process:
The assembly was relatively easy. Except the SMD leds, resistors, transistors and capacitors! They were a little bit harder to solder.
Unfortunately the Bluetooth feature didn’t work with my actual mobile phone, that has Android 4.4 (KitKat) installed. The managing App only works with Android 2.0 to 4.0.
Here are the assembly instructions and the Android app: