Either one. The reason for the pulleys is a simple redirection.
In the attached picture, the black circles are pulleys. The green one is the winch pulley, which can be moved anywhere. The red is the cable, running over the pulleys (and around the winch several times) and tying to the goalie post at both ends.
What gearbox do you recommend I go with if I use the mini CIM motor since we have it?
First of all, what OTHER motors do you have on hand?
For a MiniCIM, stock, you’ll be running at pretty close to free speed, which is rated at 6200 RPM, let’s call it 6000 RPM to account for the loading of the cable and to make some math easier–this translates to 100 revs/second. For reference, the proposed winch will feed out 7.8 inches of cable/revolution. 780 inches of cable being fed out/second is quite a lot, to say the least.
Let’s assume that you only need to feed 20 inches out to deploy the goalie post, and that you want to deploy/retract in 1 second. For this, I’ll also assume a 2.5" winch diameter, resulting in 7.8 inches of cable fed in or out in 1 revolution. That’s roughly 3 revolutions of the drum, in 1 second. 3 revs/second = 180 rpm. For a MiniCIM, that’s 6000 rpm/180 rpm or a roughly 33:1 reduction. Not too bad (I expected worse) but we gotta use a CIM-based solution due to mounting constraints, and it’s gonna be a multi-stage reduction due to gearbox design rules of thumb (no more than a 10:1 on any given stage).
VEXpro doesn’t really have anything that’ll work, unless a VersaPlanetary could be adapted to a CIM input. AndyMark has their GEM planetaries (3-stage is the only one that will work for this), AndyMark Planetaries (again, the 3-stage is the only one that will work), OR 3 Stackerboxes (1 double, 1 single) with appropriate modifications to take the CIM and stack them all. One more supplier: BaneBots. They have a P80 that you can use a PDV on that should work.
With respect to which of the above gearboxes I’d recommend, I’d probably go with the Stackerbox (which will take more work to put together), but for space reasons I’d go with a GEM 3-stage. BaneBots has gotten better, but some folks still remember past failures (and while they’re cheaper, you still need to get a mount kit).
Now here’s the thing. There are a lot of other motors allowed and/or in the kit. Some of them are lighter, some of them are slower (hint: less reduction needed), some have anti-backdrive capability. Some may be just about free (if you’ve got 15 FIRST Choice credits, the Van Door motor is a good one). Or, if your BAG motor is still available, you could throw a VersaPlanetary on there. You could also change the