And the new planimeter is here : orthogonal planimeter.
The planimeter is equiped with a disc / wheel integrator, which is more precisely than the pritz planimeter.
Concerning the functionning, the polar arm can be rotate, and when the planimeter is pulled, the yellow disk rotates. The combinaison of the displacement of the disk and the angular position of the wheel integrates the curve. And thansk to green's theorem, the line integral of the curve is equal to the surface below therefore the area.
As a consequence, the system for moving the disk is not a bevel gear but a tyre bevel gearing, which has not dead-point.
This device is more accurate than the pritz, because of the integrator system, which is not an approximation of the area but the real value.
On his website, Nico71 (Nicolas Lespour) recently posted this Lego Technic All-Wheel-Drive Rally Car. He wrote that "This supercar has the following functions :
Steering with Hand Of God and Steering Wheel
All wheel drive Transmission with 3 differentials
Fake V8 Engine
Openable Door and roof
Removable optional motorization
"The removable motorization is made with a special translated frame, on which the motors are connected. The two L motors are mounted on this frame, the lever operates a 12-tooth gear on a rack pinion, then the rack moves the frame. In first position, the motors are not meshed with the transmission, in the second position, the 24-tooth gears on the motors are meshed on the central differential of the transmission which drive the car."It has a lot of features -- see more on his webpage and on his YouTube video.
Many thank to you David, I have really no time to make update on this topic. I am very gratefull that you did.
Concerning the car, thank you for the comment, as said, it is an interesting concept at this scale, and for the building instructions, there are on the way. Stay tunned to the youtube account or facebook.