Measurement system for use in an exercise machine

1. A measurement system for use in an exercise machine, which exercise machine comprises a lifting mechanism and an engaging member for selectively engaging a number of stacked weights to the lifting mechanism such that the engaging member moves jointly with the lifting mechanism, the measurement system comprising a pair of cooperating members including a range meter and a reflector member, wherein one of the cooperating members is connected to the lifting mechanism and the other of the cooperating members is connected to the engaging member, wherein the range meter is directed to measure a distance to the reflector member to determine a distance which correlates to the weight of the selectively engaged weights.

2. The measurement system according to claim 1 , wherein the range meter is connected to the lifting mechanism and the reflector member is connected to the engaging member.

3. The measurement system according to claim 1 , comprising an operation detection mechanism communicatively connected to trigger the range meter to make a distance measurement responsive to detection of operation of the exercise machine.

4. The measurement system of claim 3 , wherein the operation detection mechanism comprises a motion sensor connected to sense movement of the lifting mechanism.

5. The measurement system of claim 4 , wherein the motion sensor mechanism is wirelessly connected to the range meter.

6. The measurement system of claim 4 , wherein the motion sensor is connected to a member of the lifting mechanism so as to sense rotational movement about a non-vertical axis upon operation of the exercise machine.

7. The measurement system of claim 3 , wherein the operation detection mechanism comprises a motion sensor connected to the engaging member, configured to detect movement or placement of the engaging member with respect to the stack of weights for detecting operation of the exercise machine.

8. The measurement system of claim 3 , wherein the operation detection mechanism comprises a proximity sensor connected to the engaging member, configured to detect movement or placement of the engaging member with respect to the stack of weights for detecting operation of the exercise machine.

9. The measurement system of claim 8 , wherein the proximity sensor comprises a magnetometer for detecting that the engaging member is inserted in the weight stack.

10. The measurement system of claim 3 , wherein the operation detection mechanism is configured to trigger the optical range meter to make a single distance measurement for an exercise sequence comprising any number of lifting repetitions without alteration of weight.

11. The measurement system of claim 1 , comprising an auxiliary sensor to detect a position of a movable auxiliary selector member of the exercise machine, which auxiliary selector member is configured to engage an additional amount of weight to the lifting mechanism.

12. The measurement system of claim 11 , wherein the auxiliary sensor comprises a proximity sensor connected to sense proximity of detection element connected to the auxiliary selector member.

13. The measurement system of claim 11 , wherein the auxiliary selector member comprises a rotatable selector member and the auxiliary sensor includes a rotation sensor mechanism connected to detect angular position of the rotatable selector member.

14. The measurement system of claim 1 , wherein the range meter comprises a time of flight sensor.

15. The measurement system of claim 14 , wherein the time of flight sensor comprises a light emitter configured to emit a periodic signal, a light detector, and a measurement circuit configured to measure distance dependent on an emitted signal and a reflected signal received by the detector.