Pink servo??

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MySolderIsOlder
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Re: Pink servo??

Post by MySolderIsOlder » Sat Mar 23, 2019 9:40 am

Talking of pink servos, does anyone know the size of the thread in the middle of the splined arbor on the s306- ie the screw that holds the arm on? I’ve tried measuring it and seems to be around 2.2 or 2.3mm but hard to tell - and not even sure if it’s a standard pitch.
Stuart (Anthony's dad)

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peterwaller
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Re: Pink servo??

Post by peterwaller » Sat Mar 23, 2019 1:27 pm

Paul I was thinking more for Cluster Bots.
The screw on the pink servo looks very slightly smaller than a M2.5.
I tried one but it wont go in more than about 1 turn so I guess it some american thread.

MySolderIsOlder
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Re: Pink servo??

Post by MySolderIsOlder » Sat Mar 23, 2019 4:55 pm

Aha - apparently US #3 machine screw is 2.3mm across the threads, which is what I make the screw supplied with the servo. So I think Peter has hit the nail, so to speak.
Cheers. Now I just need to source some threaded rod that size....
Stuart (Anthony's dad)

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LimaHotel
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Re: Pink servo??

Post by LimaHotel » Mon Apr 01, 2019 8:43 pm

The KingMax servo is tested. Ooohkay.
First off - it's too much for a DasMikro. It cuts out if I rapidly flip it backwards and forwards, and drive cuts out after a flip. This is a known problem with the DasMikro when using more powerful servos - it can supposedly be worked around by giving the servo a dedicated power supply. I mean, that'll take me seconds to do, I'd just need to deconstruct the flipper again. My god, I'm gonna make Key Grip v2 easier to work on!
As to the specs. Okay, I ain't got a clue if it's actually 10 kilos. It's a LOT of torque though. SIGNIFICANTLY more powerful than the Pink Servo. It's not battle tested, obviously, but the build quality looks solid. Gears feel smooth when manually turning the arm, uuuh... yeah. I haven't done an aggressive stall test of it or anything like that, but first impressions are good.
It's actually not quite as good at lifting heavy things as the pink was in Key Grip though - the angle of incidence between the flipper linkage and the servo arm is so inefficient in the current build of Key Grip that whilst the pink servo does kinda work, this kingmax servo just shoots straight through and warps the chassis, which is quite funny to watch actually. To be clear - that's a flaw with Key Grip v1, not with the servo.
I'll get back to you once I've stopped it from drawing power from the lemon through the DasMikro and have wired it directly into the battery, but I reckon it's gonna be REALLY impressive! I mean as it is, I can get a far more explosive / launchy flip than I ever could with the Pink!
(I'm really annoyed that this is my brother's servo now. I want one.)
Jiggy Sawdust
Jammin' Good with Weird and Flippy
The Pushbot from Mars

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MarkR
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Re: Pink servo??

Post by MarkR » Mon Apr 01, 2019 9:02 pm

I assume you use the Dasmikro to drive brushed motors, not the servo. If the Dasmikro cuts out, it's possibly due to voltage drop during the high current of the flip.

I don't really think this is Dasmikro's fault (I have not had great success with Dasmikro but I am defending it on this occasion). This should be able to be fixed by either:

* Lower resistance power wiring, to the servo. You want to create some kind of wiring loom ("Y" cable for power etc) which has nice low resistance and doesn't rely on dupont connectors etc, to ensure that the current goes to where it's needed.
* Better decoupling on the microcontroller. The Dasmikro, like all ESC, has a microcontroller in it. There is a voltage regulator and some caps on the board, but the capacitors look a bit small to me; I haven't tried to measure it. If you have a 10uF capacitor with leads, you could try soldering it across the 5v from the Dasmikro's BEC.

Are you sure it's the Dasmikro cutting out, not the receiver? I would have thought that a power interruption would affect the rx too (maybe your rx just has better capacitors in it).

Oh yes, and definitely do that thing you said "stopped it from drawing power from the lemon through the DasMikro and have wired it directly into the battery". You don't want the power going through the rx (and maybe dupont connectors)
Robots: Betsie - RaspberryPi controlled flipper bot with gyro stablisation - too clever for her own good?
Stacie - tidy flipper; 4wd driven by hair bands

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LimaHotel
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Re: Pink servo??

Post by LimaHotel » Mon Apr 01, 2019 9:20 pm

My wiring at the moment is literally: Battery into dasmikro, dasmikro into Lemon (including power to Lemon), lemon (signal, positive and negative) to Servo. Which I now realise means the servo is probably actually only running at 5v (I believe the DasMikro steps down Voltage to 5v for the rx?)
This is the basic wiring that works fine for low power servos. I... Kinda just plugged and played for a basic test of "is it juicier than the Pink?"
I'm currently pulling Key Grip apart to wire the servo straight to Lipo, so the only wire coming off the Lemon to the Servo will be the signal.
...That is how you're meant to do it, right?
Jiggy Sawdust
Jammin' Good with Weird and Flippy
The Pushbot from Mars

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MarkR
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Re: Pink servo??

Post by MarkR » Mon Apr 01, 2019 9:26 pm

Yes, definitely don't power a servo through the 5v from the Dasmikro's regulator.

I would make up a "Y" cable, with a battery connector on one end, to drive the Dasmikro on one leg and the servo on the other leg. Then you can connect the single wire for the servo pulses to the correct channel on the RX (use a dupont connector for that if you like; it will be low current).

If you borrowed the servo from your brother, perhaps make up a cable with servo connector male, so you don't need to chop off the lead.
Robots: Betsie - RaspberryPi controlled flipper bot with gyro stablisation - too clever for her own good?
Stacie - tidy flipper; 4wd driven by hair bands

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LimaHotel
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Re: Pink servo??

Post by LimaHotel » Mon Apr 01, 2019 9:28 pm

HAAAAAHAHAHAHA and I just managed to break about half the soldering trying to unplug the servo from the lemon (yeah, this is still with the end-pin lemons. I do have pinless lemons ready to swap out for, but I was waiting to do the full rebuild for that. I guess the rebuild is now happening tomorrow)
Ooohkay. Well. That's enough damage done for tonight. I'll crack on with it tomorrow.
Jiggy Sawdust
Jammin' Good with Weird and Flippy
The Pushbot from Mars

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LimaHotel
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Re: Pink servo??

Post by LimaHotel » Mon Apr 01, 2019 10:43 pm

OR I soak everything in flux and resolder it. I would deem the test a success - it holds a heck of a flip. Video on it's way.
Running on happy power straight from the Lipo it's got a smooth and snappy action, and really does hold quite the flip on my beat up Pushbot.
Jiggy Sawdust
Jammin' Good with Weird and Flippy
The Pushbot from Mars

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LimaHotel
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Re: Pink servo??

Post by LimaHotel » Mon Apr 01, 2019 11:17 pm

Jiggy Sawdust
Jammin' Good with Weird and Flippy
The Pushbot from Mars

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