Pink servo??

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Paulmchurd
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Pink servo??

Post by Paulmchurd » Sat Mar 09, 2019 9:56 pm

Stumbled across this on AliExpress while trying to find a replacement for the pink servo, which was discontinued apparently.

http://s.aliexpress.com/Njmiiaii

Seems to have all the same stats...happy buying!

Paul

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Shakey
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Re: Pink servo??

Post by Shakey » Sat Mar 09, 2019 10:23 pm

You can find a large variety of alternatives by searching for '450 servo' or '450 heli servo'. There's a whole tree of servos copying each other. :D Saying that KST is a good name that keeps cropping up.
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Paulmchurd
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Re: Pink servo??

Post by Paulmchurd » Sat Mar 09, 2019 10:33 pm

Ah that’s the key detail I’ve been missing, 450... I was searching HV or HT...so been stuck for what to use since the pink servo disappeared off hobbyking.

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peterwaller
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Re: Pink servo??

Post by peterwaller » Sun Mar 10, 2019 9:24 am

I have used these and they seem about the same spec but the wires come out the bottom.
https://www.servoshop.co.uk/index.php?p ... area=Servo

Paulmchurd
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Re: Pink servo??

Post by Paulmchurd » Sun Mar 10, 2019 6:15 pm

Why do people talk about the pink servo so much? When it seems there are plenty of alternatives that don’t seem to appear on this forum.

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Shakey
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Re: Pink servo??

Post by Shakey » Sun Mar 10, 2019 6:26 pm

The pink servo basically was the first fully fledged ready to go actual flipper servo we had. Now 'flippers' existed before then and some were capable of actual flips. But for the most part you'd really call them a lifter by today's standards, they didn't really have a 'throw' to their flips. Linkages were a bit of a struggle with a range of frankly pathetic powered servos, servos that'd die too easily or servos that while they had a lot of torque where frankly too slow (The 'Green' servo was the one before the pink servo that had ~6kg/cm of torque but was very slow). To add nearly all previous servos required a BEC to power them or were risky on straight 2S (Like the Park servos). There were some favourites like the HS82MG but I found it lacking in torque but it did have good average speed.

The pink servo was a bit of a game changer in that regards and was very easily available from hobbyking for quite cheap when it first appeared. I recall picking them up for £12. The weight of it wasn't too bad and by being happy on a 2S you eliminated the need for robust powerful BECs which are either large off the shelf or just not good enough. The range of alternatives grew over time but when you have a tried and tested that is cheaper then no real reason to try others. Plus one thing about the robotics community is that parts are only adopted once a number of 'early adopters' have proven them, such is going on with HW brushless drive and was happening to FW brushless drive (which has now found its feet). There is not really anything standing out much from experimenting people in regards to choice of servo right now, a lot of other stuff but not servos right now.

As to why people don't really tend to use anything other than it and the servos it copies/copies from/copied the same thing, frankly a lot of them just don't stack up. I personally love the pink servo as it really hit a balance of torque vs speed for our needs. Fairly cheap and lightweight I used it heavily in commissions as it'd make just about any linkage work.

In essence the pink servo (Hobbyking variant) was the preferred servo of it's group of identical servos. And that group of identical servos just had a really solid balance of stats for our needs over all the other groups.

EDIT: Eventually a new favourite will come along, and just like it's passed from component to component people will adopt the new one en masse because they get battle proven and trusted. Park HPX F's, HS82MGs, MG90's, Dys 1806s (Now Quanum 1806's), N20's (I remember when these weren't the go to!), 2s 180mah Turnigy Nanotech, Sabertooth 2x5A, NanoTwo's, Pololu 32mm Wheel; All trusted components that were used in a majority and have already been or will one day be superseeded.
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Paulmchurd
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Re: Pink servo??

Post by Paulmchurd » Sun Mar 10, 2019 8:56 pm

Thank you for all the information, I’ve learnt a lot through reading it. I wish I’d started making robots years ago now, as I’ve not had to “discover” anything but use all the recommended parts instead...N20, polycarbonate and the pink servo.

I’ve been searching for a new servo since February, I thought I had discovered an unheard of servo... how wrong I was 😅.

I’ve been testing this recently, a little slower then the pink servo but it only costs £11, weights 7.3grams and the size of a micro servo. It certainly does not flip as well but it can flip and selfright the robot. It’s pretty close to being just as good as the pink servo. I had to 3D print a strengthening horn as the 20T supplied one was very weak.

http://s.aliexpress.com/EBzENJZf

Paul

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peterwaller
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Re: Pink servo??

Post by peterwaller » Thu Mar 21, 2019 12:11 pm

I just got 3 of these D0474HT servos and they look and feel like a really nice little servo but I still need to try them in combat. As Paul says not quite as powerful as the pink ones but at full 2 cell operation and half the cost and weight well worth a try and only 10 days from order to arrival quite quick for china plus I got emails telling me when it was dispatched, received in the Uk and arrived at the local post office so great service.

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LimaHotel
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Re: Pink servo??

Post by LimaHotel » Thu Mar 21, 2019 2:00 pm

Can someone give me a real quick breakdown as to why this one would be a bad idea? From my understanding of the numbers, it just looks... good. And I highly suspect I'm missing something.
https://www.aliexpress.com/item/FATJAY- ... 88572.html?
Jiggy Sawdust (Grabber)
Jammin' Good with Weird and Flippy (Rear-hinged Flipper)
The Pushbot from Mars (4wd Pushbot)

Key Grip (Retired)

Paulmchurd
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Re: Pink servo??

Post by Paulmchurd » Thu Mar 21, 2019 5:21 pm

@Peter I think they will be very good for nanoweights.

@lima. They look amazing...The 10kg of torque could be a lie though, Chinese sellers have been known to lie...it is definitely worth a buy and do a test on them. Nice find.

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 (Grabber)
Jammin' Good with Weird and Flippy (Rear-hinged Flipper)
The Pushbot from Mars (4wd Pushbot)

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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)
Robot: Betsie - RaspberryPi controlled flipper bot with gyro stablisation - too clever for her own good?

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