The “C51 4 Bits Electronic Clock Electronic Production Suite DIY Kit” from banggood (link: link) is a nice kit and it is pretty forward to assemble it. Just follow the printing on the board. Only thing I did wrong was the resistance cascade. Watch for it, it is important to choose the right direction. Voltage is 3V to 6V.

After it is working you might wonder how you can set it. As the document in dropbox can’t be reached, here are the settings instructions.

Hold S2 briefly to change the display to show minutes and seconds. S1 is the mode switch and S2 is then used to select correct time. Hold S1 down for 2 seconds to set the clock. Set according to the following: A=Hour, B= Minute, C=”Chime” On/Off, D=Alarm 1 On/Off, E=Hour Alarm 1, F=Minute Alarm 1, G=Alarm 2 On/Off, H=Hour Alarm 2, I=Minute Alarm 2