One alarmed by wheels in old scanner (4,6)

I believe the answer is:

card reader

'old scanner' is the definition.

'one alarmed by wheels' is the wordplay.
'one alarmed' becomes 'dreader' (someone who dreads perhaps).
'by' is a charade indicator (letters next to each other).
'wheels' becomes 'car' (car wheel is a kind of wheel).
'dreader' put after 'car' is 'CARD READER'.

'in' acts as a link.

I've seen this clue in The Guardian.

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