The present disclosed technology relates to a downhole tool activation device, and a method of using the device, where the valve is configured to open when the counter device has moved an activation distance in an activation direction, a piston engaged with the counter device, having a wellbore pressure from a fluid source applied to a first side, and a pressure in a fluid reservoir applied to the second side, the piston configured to move a step distance in a first direction when the wellbore pressure exceeds the pressure in the fluid reservoir, and configured to move a step distance in an opposite direction driven solely by a greater pressure in the fluid reservoir than the wellbore pressure, and a flow restrictor in fluid communication with the fluid reservoir and fluid source, configured to restrict the flow of fluid between the fluid source to the fluid reservoir.