I am building an Arcade cabinet with a 3-sided rotating control panel. I want the rotation of the control panel will be automated. Here's a render:


However, I have a problem: locking the control panel in place. It needs to be able to hold in place against the force of players leaning on the control panel (and angry players pounding on it). It also needs to have no play and feel very solid. It can't be rocking while players are pushing the joystick up and down (some people push somewhat hard). The front panel prevents it from rotating forward, but there is nothing preventing it from rotating backwards. Note that this will be made from wood in my shop, so exact tolerances can not be expected (may be off by up to 1/8"-1/4").

I created a test setup for my original idea that used a tension latch to secure the control panel to the front. That worked well, but I would like the whole thing to be automated. Here's a video of that: http://www.youtube.com/watch?v=KK2Xa4psLp0

I have had a couple ideas but I am not sure how feasible they are or exactly how to implement them.

One idea was to use an indexing/dividing head like the one in my lathe. The rod that locks it in place could be automated via an actuator or something. But, I am not sure how to obtain one. I don't have the tools to machine anything.

Another was to use a worm screw to drive the rotation of the control panel as I have read they are supposed to provide holding strength. However, I am not sure how much holding strength and how much play will be present.

I thought about an electromagnetic brake, but I think one that would provide enough force would be way too big (and could interfere with the CRT).

I also figured solutions could be combined. One component could be responsible from preventing the control panel from turning freely under large forces (like leaning/pounding) and another component could be used to prevent the control panel from rocking due to the smaller forces (like pushing on the joystick).

I assume the problem of holding a rotating joint in place is one that has been readily solved by robotics. But I am a babe in the woods with this stuff and I have not been able to find a good solution in my research. I am completely new to automation/ME. Please let me know if there is a better place to post this question and sorry if this is not the correct place.

Edit: While posting this I had another idea: is there a way to automate the tension latch?

  • $\begingroup$ My woodwork master would say that if you can feel the junction between the two pieces with your finger tips then it isn’t good enough.... $\endgroup$
    – Solar Mike
    Oct 6, 2018 at 19:05

2 Answers 2


The force you need to rotate the panel is tiny, compared with the restraining forces to hold it in place while it is being used (and abused) by the players.

So I would separate the two functions and devise some passive locking features, for example pins that can extend and retract from the end panels and fit into holes in the ends of the rotating part.

The force required to move the pins would also be small, so you could use small electrical devices (linear actuators, small motors driving a rack and pinion, or whatever) to deploy and retract them.

  • $\begingroup$ It appears that there may be more space inside the triangular prism of the mechanism than on the sides of the console. Solenoids and pins, rack/pinion as you suggest seems to be a solid, simple solution. The wiring from the rotating to the stationary segments seems like an additional challenge. $\endgroup$
    – fred_dot_u
    Oct 7, 2018 at 16:51
  • $\begingroup$ I agree that the two functions can/should be separate and I agree that a passive locking feature seems best. I have thought of the pin solution you described (using an indexing plate), but the issue is that the pins and holes would need a precise enough fit so that there would be no play and I don't think I can realistically get that tight of tolerances. I feel like the solution will need to pull the rotating part and the front panel together (like an automated version of a tension latch). This would transfer the movement to the front panel which would be completely stationary. $\endgroup$
    – Mike
    Oct 8, 2018 at 13:58

The class of device is called an intermittent. It is used, for example, in a film projector to advance the film one frame at a time. It is also used in the packaging industry to fill bottles and such from a stationary fill head. The gadget you are wanting is probably the cammed geneva wheel.


  • $\begingroup$ Also known as “interrupter” or synchronisation mechanism... $\endgroup$
    – Solar Mike
    Oct 6, 2018 at 22:07
  • $\begingroup$ I see how this class of device could be used to rotate the control panel in increments. But I am not sure how it solves the holding force problem. Thanks. $\endgroup$
    – Mike
    Oct 8, 2018 at 13:47
  • $\begingroup$ @Mike Look at the video. The driver wheel has a cam that locks the Geneva wheel in place. It is only free to move when the driver cam is cut away, and this is designed to correspond with the pin engagement. $\endgroup$
    – Phil Sweet
    Oct 8, 2018 at 20:56
  • $\begingroup$ What prevents the driver wheel from rotating when force is applied to the Geneva wheel? I may be missing something here. $\endgroup$
    – Mike
    Oct 9, 2018 at 22:00
  • $\begingroup$ @Mike You park the driver wheel with the pin facing away from the Geneva wheel. There is no engagement, so no torque on the driver wheel, just the cam sitting in the indent of the Geneva wheel. $\endgroup$
    – Phil Sweet
    Oct 9, 2018 at 22:05

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