This study used a standard keyboard with a newly developed finger-pressing position detection program (FPPDP), i.e. a new software program, which turns a standard keyboard into a finger-pressing position detector, to evaluate whether two people with developmental disabilities would be able to actively perform fine motor activities to control their preferred environmental stimulation. An ABAB design was adopted in this study. The data showed that both participants' target responses (i.e. fine motor activities) significantly increased (i.e. they performed more fine motor activities to activate the environmental stimulation) during the intervention phases. The practical and developmental implications of the findings are discussed. (Contains 4 figures.)