Actuator apparatus using a pin-puller

An electrically-controlled, pin-pulling valve includes a pull pin (e.g., a pull piston) and a chemical propellant. The valve is configured to, using the pull pin and the chemical propellant, actuate from a closed position to an open position to activate a downhole tool. For instance, the pin-pulling valve may, based on an activation signal, activate the chemical propellant, which may cause the chemical propellant to react. The activation of the chemical propellant may cause the pull pin to withdraw from an extended position to a withdrawn position. The withdrawal of the pull pin may cause the pin-pulling valve to open, allowing hydraulic fluids to flow through a port associated with the downhole tool previously sealed by the pin-pulling valve. The flow of the hydraulic fluids may activate the downhole tool by exerting hydraulic pressure on the downhole tool.