Digital movement measuring device

A device for measuring movement of a mobile element moving in at least one direction, comprising:

• a light source adapted to emit a light beam;
• at least one optical member adapted to intercept the light beam emitted by the light source and adapted to be attached to said mobile element in order to have a same movement as the mobile element relative to the light source;
• at least one pixel-type sensor, separate from the optical member and fixed with respect to the light source, adapted to capture a modified light beam emerging from the optical member, the optical member arranged on a path of the light beam emitted by the light source such that the modified light beam emerging from the optical member is determined by a relative position of the optical member relative to the light source,
• the sensor comprising light-sensing pixels disposed so that at least some of the pixels receive illumination from the modified light beam that varies with the relative position of the mobile element in accordance with the movement of the mobile element;
• a comparator module adapted to compare values obtained from the pixels of said at least one sensor with first and second distinct thresholds, and to assign logic values to the values as output data, such that:
• all luminous values below the first threshold are assigned a same first logic value,
• all luminous values above the second threshold are assigned a same second logic value, and
• all luminous values situated between the first and second thresholds are respectively assigned converted values adapted to be processed by the calculation means;
• and
• a calculation module adapted to determine and produce an output indicative of the relative position of the mobile element from the output data from the comparator module.