Pllease help me decide which servo to buy!

Lynxmotion Legged Robots
1

lynxmotion.com/Product.aspx? … egoryID=38

the 5955 has a built in heatsink, how important is this? ive been staring at the 3 best servos LYNX has to offer for hours now and im not sure which to buy.

5955 - 115 bucks, 333 torque, 140 degrees, TG…
lynxmotion.com/Product.aspx? … egoryID=38

5980 - 110 bucks, 417 torque, 180 degrees, SG …
lynxmotion.com/Product.aspx? … egoryID=38

5990 - 125 bucks, 417 torque, 180 degrees, TG …
lynxmotion.com/Product.aspx? … egoryID=38

Im so confused, what the heck should I buy that will work with SES brackets and requires no extra bracket work (such as enlargening bracket holes)?

I want metal servo horns, with the first one does not come with, yet it has a heat sink which I do not know the importance of. Please help im so frustrated :imp: !

2

I would say that the heatsink is essential because the non-heatsink versions have been shown to smoke, but I have no direct experience with this. Evolution and others do. Of the above three, the 5990 is the best choice despite the higher cost. The 5980 and 5990 are the newer (supposedly more reliable) models, and the 5990 is the best option since it has the heatsink. If you are spending $110 on a servo, you might as well spend $125 and get the heatsink plus lighter weight titanium gears. I’m going to use the 5990 when I get up the gumption to build my humanoid.

The 5645 is another popular option, and metal horns are available.

lynxmotion.com/Product.aspx? … egoryID=93

I wouldn’t expect to be competetive in Robo-One type competitions with the 5645, but it would definitely get around if you just want platform for experimentation. And by all accounts the 5645 is extremely reliable.

3

Good reply!

How much noticable difference is there between 417 and 333 oz/in torque (and I dont mean the math)?

How do you know the 5990 has a heatsink? It doesnt say that anywhere on the spec pages. Is the 5990 also competitive during ROBO-ONE?

TG is better than SG right? Also, will the 5990 work with SES? It has that stupid pivot thing in the back, any way to get rid of it? Or make it work without any tools?

4

I recommend running them at 6V, which would yield the lower torque number. It’s a huge number either way, so torque won’t be your problem in any case. 8)

Well, I’ve held them in my hand, and I’ve seen the pics, so it has the heatsink. It could definitely be competetive if you are competetive. :slight_smile:

I would say the weigth difference makes it worthwhile. It’s not a deciding factor though; the heatsink is the clincher.

You would be wise to embrace the bottom pivot. It makes for much stronger joints. All you have to do is make the hole bigger with a reamer. It’s very easy to do … just put it in the hole and turn it back and forth until the pivot fits. Trust me, this is the solution you want. Just buy this $10 tool:

www2.towerhobbies.com/cgi-bin/wt … XVJ31&P=ML

Good luck. Oh, and buy your servos from Lynxmotion. I believe in supporting the folks who support us. :wink:

5

Hmm, that tool will make the hole bigger I see, but it wont look “homemade” will it? I dont want the hole becoming another shape and looking terrible if you get what Im saying.

Another question, the 5990 specs state it runs on “Voltage = 6.0 - 7.4vdc” … will the SSC-32 equipped with a MINI-ABB+BASIC ATOM PRO 28 PIN work with these?

I always thought servos ran on 4.8 - 6V? What kind of battery do I need for these to work awesomely? A 7.2V one?

Oh and yes, I plan to buy EVERYTHING from lynxmotion from now on. Ever since my RN1 came in, I trust no one but them. Thanks for the help man, you’re great.

6

Lower left corner of the spec sheet]: MOTOR HEATSINK

7

Reamers only make round holes. You’d have to be a complete fumble-fingers to screw it up. Once the hole gets close to the right size, slow down and check it every couple turns. Make the hole just big enough.

That’s a non-issue.

These servos are rated for a higher voltage, but more volts means more heat, and heat leads to smoke. I’d play it safe with my $125 servos and run at 6V. They will have plenty of torque and a longer lifetime.

8

Cool, what kinds of brackets do I need to be able to make a robot using these servos?

Will the LONG C and the MULTIPURPOSE be enough?

And A-BOT: Running at 6V wouldnt be considered “low voltage” would it?

9

This is a loaded question. There are a lot of different ways to do it. You need to hunker down, look at some pics, and think it through. If you can’t do CAD, just design each limb in your mind (or draw sketches) and write down the parts you would need, then add it all up. There might be some parts lists on the forum, but you really should try to come up with your own configuration.

Or if you have the cash, you could just buy a whole bunch of brackets and treat it like a Lego kit, you know just work through it, then sell off the extras. You will need more than just multi’s and C’s to make a whole humanoid.

As you originally posted, it’s 333 oz/in at 6V. That’s not “low” anything.

10

Of course, such as feet, electronics carrier, etc…but Im talking about the joints in general with relation to the extra pivot the servos come with.

I havent seen a picture yet of a full joint made with these servos, only one with a MULTIPURPOSE attached to it after being reamed. To be honest, I cant imagine how these joints will look with this type of servo. I will try a CAD, hopefully LM offers downloadable 5990 models.

11

Beware of the specs on the digital servos. A while back a former poster apparently bought a bunch of them for the extra “strength” they spec and then found that they burned out under extended load in his application. You probably can do a search for the discussion. At $125 a pop, you need to do some research up front.

12

You have a misunderstanding somewhere. These servos are not used any differently. All the configurations are the same as with “standard” servos. :wink:

13

I think you are referring to a thread on the older 5995, which the 5990 replaces:

lynxmotion.net/viewtopic.php?t=2152

Also, in that thread it was a large arm, not a humanoid. I’ve not seen a thread where someone has smoked the 5990, but it’s certainly possible to smoke any servo.

I just wanted to reiterate that it was the older servo that smoked consistently, and Hitec replaced it. But I agree with zoomkat’s core point, which is that we don’t have much anecdotal information on the 5990. Maybe no news is good news in this case. :laughing:

14

I hope I have a misunderstanding, because the way the spline in the bottom of the servo looks, it seems like SES needs to be modified like hell. But I’ll take advantage of the spline through more research.

A-Bot, Im reading other threads and I noticed you were asking how long these things run before they need a cool time. Now say the 5990 ran for 20 minutes before needing a cool time, does the word “ran” here mean consistently changing degrees with load on the servo or does it mean just talking a walk in the park, then bam you better cool off or it dies?

& Trust me, Im doing as much as research as I can on how to handle these babies so they dont kill themselves and so they can last long time. $125 dollars a pop, I’ll treat these servos like they are gold. Well, these things actually are engines in a box, or titanium gold :laughing:.

15

Yup, I’ve been down this road. I’m going to build a 5990TG humanoid, but I’m going to wait until December at the earliest. I’m building an aluminum CH3-R hexapod with 645MG servos first.

These servos have overload protection, so the servo will just shut down if it gets too hot. In theory it shouldn’t smoke, so your investment is safe.

My conclusion is that these servos should be very reliable at 6V. Look, here is a thread with video of a large, complex 5990TG SES humanoid:

lynxmotion.net/viewtopic.php?t=1989

Watch that video and then try to tell us that the 5990TG is not compatible with the SES. He uses practically every bracket in the kit, and that thing kicks butt! :slight_smile:

16

Just a couple more factors in the comparison.

The 5995, and also the 5645 are based on the standard Hitec digital servo, and are programmable by the HFP-10 for endpoint, deadband, zero, etc…

The 5995 does not have a heatsink, nor does it have any motor cutoff if the motor has high current for too long.

While the 5995 previously represented the best perfomance top end to the Hitec digital range, the 5990 is so much better, it would now be best to avoid the 5995 unless you really want the ability to program with the HFP-10.

The 5990 and 5980 are HMI based servos. They comply to HMI v1.1, which besides normal PWM operation, the can also read position by PWM, change performance parameter sets by PWM, and are serial controllable as well. However they are not programmable by the HFP-10, and Hitec have not yet made the HMI serial programming software available.

The SCC-32 cannot use any of the additional HMI features, but other controllers can, and maybe the SCC-24 will too.

The capability to get feedback from the servos for load sensing is becoming much more commonly used in bipeds, that it is worth having if you are spending a lot of money on servos, even if you don’t use it initially

I have tested the 5990 and it does indeed have overload protection and full HMI v1.1. I beleive the 5980 will also. The heatsink is also an advantage to the 5990, since the aluminium body is more conductive, so you can feel more quickly if a servo is under heavy load and warming up

The 5990 is noisy, and the noise is at rather a high pitch. Some find this annoying.

The only robot that I am aware of using the 5990 is Rooks Pawn 3 from Matt Bauer. Maybe he could give you some input on living with these in a biped.

Finally, you might also consider the Open Servo based Gearhead motor servo that is being developed.

17

ribbotson:

Alright before I go on blabbing ignorantly, please tell me what the heck HMI is, and why is it so important? Ive never heard of HMI for other servos, and what is this “cable” you’re speaking off? Can I not program the 5990 using a DB9 CABLE?

If the SSC-32 cannot handle the 5990’s full power, what can? When wil the SSC-24 be releasing? Please recommend me somewhere because Im trying to make a large order list from LM but I see i might have to extend to one more site for electronics.

Im new to servo purchasing, so if Im going to be buying something this high-quality I need something controlling it high quality as well. Thanks.

18

HMI is the Hitec Multiprotocol Interface, which is why no other servos have it yet. It is designed to be compatible with simple PWM controllers (SCC 32), yet extensible to Hitec C3024 for PWM position reads, through future serial control at 19.2K.

The servos have the serial protocol, but Hitec, have yet to release their cable and software to configure the servos. The cable is trivial, but the software is more important.

Your major investment is in the servos, not the controller, so if the SCC-32 does what you want for now, then use it.

I have seen mention of the SCC24 in other parts of this forum, though having less ports it will have bidirectional processor access to all ports which is required for HMI or other feedback protocols.

The open servo can use the SCC32 for control, whille using a seperate I2C connection for feedback.

You may not acheive the best combination in one step, but I think you will find the 5990 and 5980 the best future proof investment as far as Hitec servos are concened.

19

Well Im going to purchasing these servos at the end of the year, so hopefully by then lynxmotion will offer everything I need to get these servos working. Ill keep the SSC-32 in mind for now incase the SSC-24 doesnt release but hopefully it will.

Does anyone know much about the three ROBOT SERVO BRACKET sets in the bottom of this page: lynxmotion.com/Category.aspx?CategoryID=87

They are specifically made for the 5990/5980 and im wondering what so different between the 3 sets, and whats so different between these 3 and the lyxnmotion brackets? I mean, are the long “C” and “multipurpose” LM brackets not enough for these servos?

20

hey guys,

how about the “Hitec 24 Servo MR-C3024 Microcontroller Board” thats included in the RN1? That has HMI capabilities, wouldnt it be enough for the HSR-5980/5990?