Determining the ripeness of fruits is a major point of interest for the fruit industry, since this dictates harvest time, storage conditions and edibility. However, the current state of the art method, which is the penetrometer, performs destructive measurements on the fruits. Recently, ripeness-estimating grippers are being developed to overcome this destructiveness. However, the extra tactile sensors used to achieve this increase complexity, costs and susceptibility to wear. Therefore, in this paper, a gripper is designed that can determine the grasped object's stiffness without using additional force or pressure sensors, but instead estimates force from actuator calibration data, position sensor readings and the control signal. The gripper is designed to be affordable and simple to fabricate to facilitate potential commercial use in the end. To achieve this, a compliant linear guide is designed with on each of the two ends a gripper finger. The mechanism is printed as a single part on an FDM 3D-printer out of PETG, which facilitates the ease of fabrication. The chosen actuator is a solenoid actuator and a Time of Flight (ToF) distance sensor is chosen for position recording. To enable the device to measure object stiffness, calibration of the actuator and the mechanism's intrinsic stiffness is performed. To test the mechanism's performance, calibrated metal compressive springs with a known stiffness are used as test object for the gripper. The stiffness value that was estimated by the gripper is then compared to the known stiffness calibration value. The measured stiffness values differ by 1.0%-8.0% from the calibrated spring stiffness values, which on the low error value side compared to general stiffness estimation methods. This implicates that the gripper works satisfactory in terms of stiffness estimation accuracy. Therefore, it can be stated that the main objective of this project is achieved, while also keeping the device low-cost and simple to manufacture.