Antweight Servo speed

Hi. Building my first Antweight with a flipper powered by a 2H SV metal geared Antweight servo from the BBB shop and a Fly Sky FS-i6X. The flipper is controlled by channel 3 throttle control. Is there a way to speed up the movement of the servo? I’ve set the throttle curve to 0-100-100-100-100% so it moves immediately the throttle lever is moved but the motion is slower than I need. I can look at the length of the servo arm etc. but is there a way to speed it electronically?

Typically it’s a mechanical solution with linkages to help with speed once you’ve set the transmitter to go max speed in one go.

Great diagram from Shakey here: Newbie from the North East - #2 by Joe

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Also worth asking, are you running the servo off 2s directly or though a 5/6v BEC? Won’t be worlds apart but every little helps. Hard agree it’s going to be mostly sorted with linkages.

Pictures might help too.

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Really helpful link the geometry. But can you help me with the “set the teansmotter to go max” bit. As i said, ive set the throttle curve to go straight from 0% to 100% so theres no lag when the lever is moved but thats a position adjustment. Can I adjust the speed of channel 3 on the FS-i6X?

I think if you’ve already set it to go from 0-100 then that’s as fast as you can probably get it transmitter side on FS-i6 (see section 5.8 in the manual) On other transmitters I’ve found you can set the % to like ±125%

You can also extend the range of the servo with a servo extender or malenki’s servo stretcher mode but I don’t think that would increase the speed.

Thanks. Im not using a BEC, the servo is plugged direct into the BBB 4 chanel receiver. Is that the best scenario? We seem to have plenty of power and the desired degree of movement but the time for the move is too long.

Nice looking bot! I think you’re using one of our dual ESCs and if you are then there’s a built in BEC powering the receiver (and servo) at 5V.

You want to wire the red and black wires of the servo in line with the battery to get the full 8.4V and you’ll get extra beans out of the servo :slight_smile: @Nick_DSC is making a new wiring diagram for me for this at the moment in fact!

Diagram for malenki for now but the same red and black wires apply:

Hope that makes sense.

Yes, most helpful. The only difference here is that we are using a 7.4v 450mAh battery, would you recommend swapping the battery for a higher voltage. It’s our first bot and we’re weighing in at 153g so need to shave a bit of weight anyway. Direct soldering the wires to the receiver is on the cards too!

Higher voltage won’t really help. 2s is 7.4v nominal or 8.4v fully charged and honestly that’s the sweet spot for ants. Just wire in your servo so it’s seeing full battery voltage not regulated and you’ll notice the difference.

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The battery is 7.4v nominal - it’ll go up to about 8.4v at full charge, down to 6ish fully discharged. Echoing what Joe and Harry have said, wiring it to the battery connector rather than the receiver will give a decent boost. The receiver runs off a 5v battery elimination circuit in the dual esc, so you should get a 40%ish speed boost

I wouldn’t recommend swapping the battery out for a higher voltage one. Once the servo is running off of unregulated battery voltage it’s pretty close to its maximum.

Unfortunately I think you’re somewhat limited with how much of a flip you’re going to get from the servo. My back of napkin maths says a good throw could probably manage about 10cm horizontally max. Most people use them more as lifters than flippers because they don’t have enough power in them to properly throw a robot. Swapping to the new silver BBB servo would give you that extra bit of power, at the cost of a chunk of extra weight (and cost!)
I’m aware that’s a bit of a downer, but lifters are super viable! I’d say do an event or two and see how you feel about the bot after that

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Thanks for all your replies, it has been really very helpful. I will report back.

Awesome stuff!

Early exclusive preview of the new diagram for ya :wink: (you’d want the HV servo wiring)

edit: now live on our ant guide page.