"Karma" comes from Sanskrit "To do". If you perform any action willfully and awareness is involved, then it is karma. So mobile and any instruments don't have any awareness, so it cannot be considered as karma. Yog meaning unite to greater goal. Karma yoga is a method to convert everyday action to elevate our consciousness.
What bhagavath geetha says about Karma.
अधिष्ठानं तथा कर्ता करणं च पृथग्विधम् |
विविधाश्च पृथक्चेष्टा दैवं चैवात्र पञ्चमम् || 14||
adhiṣhṭhānaṁ tathā kartā karaṇaṁ cha pṛithag-vidham
vividhāśh cha pṛithak cheṣhṭā daivaṁ chaivātra pañchamam
Bhagavad Gita 18.14
"The body, the doer, the various senses, the many kinds of efforts, and Divine Providence—these are the five factors of action. "God is seated within the body of the living being as the witness. Based on their past karmas, he also grants different abilities to different people to perform actions. We can call this Divine Providence."
For example, some people possess the acumen for earning huge amounts of wealth. Their acquaintances become astonished by them Brilliant financial analysis of complex situations. They also seem to be lucky with The risks they take. This special intellect is granted to them by God.
Similarly, Others seem to have God-given talents in fields such as sports, music, art, literature, etc. It is God who bestows people these special abilities, in accordance with their past karmas. He also grants the results of the present karmas. Hence, he is listed as one of the factors responsible For action."