We have developed a prototype for a instrument that is able to calculate the size of a load on a lorry. The measurement is done by monitoring the acceleration and retardation of the carrying vehicle and subsequently calculating the resulting load. Our assignment was to verify this theory by creating a prototype for the collection of measuring data and calculation of load. The instrument was developed using a PIC16F873 RISC-processor. We developed a program for the PIC-processor to achieve a measuring instrument that is easy to use and presents diagnostic information and the results on a display. Additionally, the user can also by the use of different menus, input calibration values or make a measurement. Our results show that the prototype validates the theory and reaches our requirements when simulated in a laboratory environment. However it is not tested in a real-life environment and therefore it will need additional development before it is viable as a commercial product.