The volume control is on the backside. You can adjust the volume of the button sound and the alarm. However, since it is an analog rotation system, a small second hand noise may be generated when the motor is moved.
2. Are time cards compatible with the minee card version?
No, the time card is only compatible with the card version.
3. Can it be compatible with iPads, Galaxy pads, etc.?
No, it is not compatible with the pads.
4. When the colorboard is full, there is a bit of white part. Is it normal?
It is normal. It's the area to allow space for the color board to rotate.
5. I want to open the backboard easily.
If it's your first time receiving it, it might not open well because it's new. Press hard on the middle of the cover, and open it by hanging your fingertips on the groove of the cover.