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  1. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    The calculations so far have assumed the cam presents a constant slope to the cam follower. In reality that won't be the case (at least for the usual spiral forms), so your refinements need to take actual slope into account in calculating force, torque and acceleration. Sorry, but I don't have...
  2. Alec_t

    Can you help me deactivate bluetooth from my mobile smart fridge (with picture) ?

    That zig-zag trace top right is the antenna. You could remove a chunk of the trace at its lowest point (as viewed here) to reduce signal strength.
  3. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    Have you decided on your cam profile yet? I didn't realise how many spiral forms there are.
  4. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    The post #124 figures look good (apart from all those decimal places!). I see how the discrepancy arose. In post #109 you have typed 1.125.... as the distance s, but instead used 1.25.... in the calculation.
  5. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    t^2 = 0.25^2 = 0.0625. 2*s = 2*1.126 = 2.252. 2.252/0.0625 = 36.032. If your calculator says otherwise, treat it to a new battery or bin it :). How did you get the 9.80665 figure?
  6. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    Yes, assuming you have ten scissor stages (levels).
  7. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    Agreed. It's made the same error. I suspect that, in the absence of anything similar in its training database, ChatGPT may have simply regurgitated the text you posted ! Yes. Btw, your calculations assume you are lifting the load 1.26m, but the cam will only move the load by (Rmax-Rmin) *...
  8. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    Your value for a is wrong. The force also has to overcome gravity (I've edited post #108).
  9. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    Yes. To lift move anything a distance s in time t involves an acceleration a given by a = 2s/t^2. That requires a force ma, where m is the mass of the thing. {Edited}
  10. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    Average slope = (0.126-0.05)/(2 x 3.14 x 0.088) = 0.137. Since this mythical frictionless slope is linear and constant, the horizontal force to move the cam-follower up it will be constant (the same at Rmin and Rmax) at ~ 3.05N x 0.137 = 0.42N. So the torque at Rmax would be ~ 0.42 N x 0.126 m...
  11. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    ... because you are not taking the slope factor into account. Unless you know the cam profile (i.e what is the relationship between radius and rotation angle) and allow for friction you can't expect an accurate answer for the torque.
  12. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    That's where the maths starts getting tricky. Think of the cam-follower climbing a slope presented by the cam spiral. The precise shape and length of the spiral will affect the relation between torque and vertical force at any rotational angle of the cam. The formula for the length of the...
  13. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    It won't. As I said originally, "If the platform is stationary and there are no horizontal forces acting on the mechanism, then the vertical upward force at each of those pivots must equal the weight of the (loaded) platform.". The applied upwards force must exceed the downward load if you want...
  14. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    I can't, but I'm sure Google can.
  15. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    Yes.
  16. Alec_t

    Micro parts

    You would have to check the datasheet for the Bluetooth module, but I'd be surprised if the module also had LED control features.
  17. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    Yes and yes.
  18. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    I didn't say that at all. I said there is no mechanical advantage, meaning the applied upward force = 1 x the downward load. To get a mechanical advantage you need to apply a horizontal force between the left and right pivot points at the bottom leve, such as is done with a screw mechanism in a...
  19. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    For the arrangement in post #34 your input force is applied to the pivot at level 4. If that pivot moves a distance dy vertically, then the corresponding pivots at level 3, 2, and 1 will move vertically by 2*dy, 3*dy and 4*dy respectively. The load platform is a half-level above level 1, so the...
  20. Alec_t

    I want to know all of the maths concerning this scissor mechanism!

    I think if you swot up on the lever principle and the moment of inertia of a rotating body, plus Newton's Laws, you will have all you need to do your calculations.
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