Funny Toy : Oscilloscope

I got this electronic toy from Taobao, i want to have more experience on soldering and putting different components on the PCB and making them work. After 3 hours in soldering and 1 hour in debugging, i finally make it works

https://v.youku.com/v_show/id_XNjAyNDAwNDY2OA==.html?spm=a2hje.13141534.1_3.d_1&scm=20140719.manual.240103.video_XNjAyNDAwNDY2OA==

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