How to motorize expansion

Hello, my team and I find a lot of string launchers on youtube but not many with motors. Also, we don’t have pneumatics and aren’t able to use them. We tried motorizing on our own but the motor had too much resistance against the rubber bands, and because of that we weren’t able to launch them. Does anyone know how to motorize the string launchers? For example Vex spin up expansion tutorial! - YouTube
New smaller version of the string launcher vex spin up - YouTube

It would help if you included a picture of your creation - it may well be that it can be made to work.

Mb, the second video is the launcher that my team made.

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I give you awful sketch!

Have motor under purple area , yellow shaft through hole with green rigid bar (c-channel, lock bar, … anything to replace your thumb in video). Rotate green bar clockwise and your mechanism might release…

just one of a million different solutions…

work it through and find a solution that works for you.

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Thanks, this helps a lot we have been looking for a solution for a while now.

Our team used this for a while. It can get up to 27 points

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Oh, yeah I have seen your expansion on youtube we just could figure out how to build it since the gearing really weird.

I would use a gear ratio that adds torque (power) and add that on somehow, perhaps a 60-36 gear ratio (input output) with slipped gears that release the mechanism? You could also try releasing the tension of the rubber bands slightly if it is too much on the motor.

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My team has a similar issue, is there any way to build a good multi-string expansion with just one motor? We also don’t have a whole lot of open volume to build it in, so we’re struggling to make a functional design.


So slipped gears allow the expansion properly launch?

Worked for me. Use rubber bands/other to add tension, and when it reaches the slipped part it’ll launch forward as it tries to release the tension. you might have to experiment with the number of gears you slip though…

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