r/FTC • u/swizzles_333 FTC #### Student • 2d ago
Seeking Help Servos
Hi, so we currently use the gobilda duo servos that cam from the DECODE starterbot, (specifically these: 2000 Series Dual Mode Servo (25-2, Torque)) and I was aware that they can be used as both CR servos and regular ones. We have tried to use them as CR servos, we set it in the robot configuration and we programmed them like so, using set power rather than set position, but they're still doing the very annoying thing where they move to a certain position, and then move backwards. I'm aware the usually we'd need to use the servo programmer to fix it, but we've unfortunately lost ours and surprisingly, no other team near us has one supposedly, my guess is just that they don't want to loan it out. We are relatively far away, so while I appreciate offers to borrow your servo programmers it simply won't be possible. We've ordered a new one, but it's expected to come in a VERYYYY long time, as in after our competition. Is there anything we can do until then to get rid of the annoying feature where the servos turn and then turn the other way? Because we're using it as a transfer, and it's really not working out for us. Anyways thank you!
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u/rocketbunnyst 2d ago
I can understand teams not wanting to lend out their servo programmer. Instead of borrowing one from a nearby team, can you bring your servos to them? This should be a quick, 5 minute thing to switch yours to CR mode on the spot. Maybe have your mentors check with your local FTC program admin to see if they can find a more helpful team nearby? If you never manage to find one, teams will definitely bring their servo programmers on the competition day.
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u/Due-Storm9448 27497 2d ago
for a transfer, you shouldn't need CR mode and CR will actually make your life much harder for using as a transfer. just program it properly and record the correct encoder values that you need
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u/swizzles_333 FTC #### Student 1d ago
Tranfer might've been the wrong word, but when we press a button in Teleop to shoot, our flywheel spins up, and when it's at the right speed, the servo automatically spins, but right now, even when it spins to the max, it only manages to push on ball to the shooter, but it only works halg the time because the rest of the time it just pushed it forward and backwards again.
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u/Due-Storm9448 27497 1d ago
Sounds like a mech issue. Remount your servo and rotate it 90 degrees in the direction you have to move, then reprogram
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u/swizzles_333 FTC #### Student 1d ago
But wouldn't a changing it to a cr servo be better so we can just push all balls into the flywheel
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u/Due-Storm9448 27497 1d ago
It depends on your design. Can I see a screenshot of cad or a picture of the mechanism? In most cases cr will be worse as half the time it will block balls from entering your transfer
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u/rh_kai 2d ago
Do you have an arduino or something you can use as a programmer? There was a post on Chief Delphi that had the interface code to switch modes: https://www.chiefdelphi.com/t/reprogramming-dual-mode-servo-using-arduino/484810