Hi,
I was just wondering something for the BRAT I’m hopefully going to get soon (maybe somebody from US can bring it to France when he comes, and the price it will be more affordable):
Will the 422 servos still work well when I add a bot board + another 422 for a turning GP2D12? Hope they will… And BTW, are there better servo choices for a sensor-turning servo?
I am building a BRAT now. I am not going to use the HS-422 servos though. I’m going to use HS-475 servos instead because I don’t think the 422s are powerful enough and I don’t want a lot of 422s I can’t use for other stuff. The HS-475 is going to be the minimum servo I will use for most things.
I have a custom pan/tilt turret on my current robot and it uses 422s. The tilt (up/down) servo can’t hold the weight of a 3" U channel and two sensors with their mounting brackets in position, even when controlled by an SSC-32.
I suggest not using 422s for any robot. The 475s are not that much more expensive - just $5.00 difference in price for a beefier servo.
8-Dale.
Has anyone used the SG5010s?
Yep - any good… yes I know cheap means lower quality but are they too low? Too jittery? Too well, ■■■■■■
I don’t know if they are any good since I have never heard of them before now. I wonder how they can be sold for $9.95 each when they supposedly normally sell for $39.95 each if they are really good servos.
The specs claim they have a coreless motor and dual ball bearings. I am tempted to order a couple if I can get them for $9.95 each and try them out.
8-Dale
TowerPro also makes the infamous MG995 “Digital” servos for 12-15 bucks. They are junk for any leg applications such as biped or hexapod. Very jittery and poor gear construction. Caveat Emptor!!!
Ah, OK, things make more sense now, so I think I will steer clear of these and stay with HiTec all the way. I want reliable servos, not flakey ones. 
8-dale
But the BRAT combo kit (which I’m about to get) and the other no electronics kit have 422s included!
And since they should work, will their torque be alright to hold the sensor turret too?
If you are just using the servo to pan side to side, I’d think the 422 would be alright for that. But like linuxguy said, 475’s are better. If you already have a 422 for your turret, try it.
Towerpro is well known in the R/C plane world. They make brushless motors and ESC’s (speed controllers) for airplanes that look like exact copies of other leading brands but are half the price. They have a well esablished reputaion for their products being below average in performance. For the price they are not bad, but don’t expect any of their stuff to perform like the original they are trying to imitate. Basically, all their stuff is cheap for a reason.
So… the SG5010 are cheap and probably jittery but no-one has used them yet… I just need some servos for my biped but I’m on a low budget. Hmmm looks like I’m gonna have to start saving to increase the budget… 
What now causes the jittery behavior? Is it because the control board uses cheaper less powerful components or is it mechanically flawed? i.e., gear train, motor. What if you took the servo and swapped out the control board with something like a OpenServo control board and convert them to digital servos. The OpenServo board has a built in H-bridge, Control over servo position and speed, Feedback of servo position, speed, voltage and power consumption. or is motor itself just not able to hold the precision?
The boards are fairly cheap so to do a swap would be less than new servos. openservo.com/
the servo jitter as they try and hold posistion, its a mechanical thing
yes, its because of the motor
The jitter also happens when you try to have a servo lift or move a load that is too heavy for it. It jitters if it can’t hold position and an SSC-32 is trying to make it hold there. The servo might drop down a bit and the SSC-32 would try moving it back into position, same thing happens again and again.
8-Dale
Jittering can also be caused by RF interference or loose servo leads.