感心 and 感動: admiring an action and being moved by a scene or memory
Compare admiration for regular practice or self-initiated tidying with emotion prompted by a scene or letter. Read the target of the response without ranking the words solely by intensity.
Admiring a worthwhile action
感心（かんしん） means admiration or being impressed. 毎日欠かさず練習する姿に感心した。 describes admiration for the way someone practices every day without fail.
弟が自分から部屋を片付けたので母は感心していた。 says that the mother was impressed when the younger brother cleaned his room on his own. 自分から preserves his initiative, while 母 identifies the person reacting.
A scene or memory that moves someone
感動（かんどう） describes being moved or the resulting emotion. 舞台の最後の場面に深く感動した。 expresses being deeply moved by the final scene of the play, naming both the scene and the degree 深く.
祖父の手紙を読むと、当時の感動がよみがえった。 says that reading the grandfather's letter brought back emotions felt at that time. Keep the letter as the trigger and the earlier emotion as what returned.
Compare the focus of the response
In these examples, 感心 recognizes the merits of consistent practice or self-initiated tidying. 感動 names a moving experience involving a scene or recalled emotion. Both responses can occur together.
Do not restrict 感心 to people and 感動 to works, or say that one is always stronger than the other. Spoken praise and tears are also separate actions that these sentences do not necessarily report.
In 弟が自分から部屋を片付けたので母は感心していた。, who acted on their own and who was impressed?
Show the answer and why
The younger brother cleaned his room on his own, and the mother was impressed. Keep the initiative marked by 自分から separate from the mother's response.