My uncle gave me his Lynx 5 arm a few days ago. My guess is that this arm is from 1998 since that is the copyright date on the manual. The design of the arm is A LOT different from the current one. It uses a black enclosure box to hold the servo for the rotation and for the electronics. I noticed that the arm is built with 6x Hobbico Command CS-51 servos rather than the Hitec servos used today. I spoke with ItalianGuy on MSN and he said that Lynxmotion did use Hobbico servos back in the day. I tried to find specs on these servos but haven’t been very successful. I haven’t found many signs of these servos ever existing.
So, I was wondering if anyone remembers these servos and if they have a specs sheet for these servos. Would you say these servos are ok for making arms or modifications for a BRAT? What sort of torque would you need to make a 2dof arm for a BRAT?
The CS-51 is a Hitec HS-300. Open it, you’ll see a Hitec on the chip on the control board. It was the worst servo they ever made. Didn’t know it at the time, but it proved to be a real POS. We switched to the HS-422 when we started noticing the trouble. The problem with the servo is the potentiometer IS the output bearing. So pressure added to the final gear was supported by the pot alone. It was ok for some apps, but real bad for others. If they work for you, then have a nice day. If they jitter or have trouble holding position, then use the control board to power other devices, or pitch it in the trash.
Maybe… Arms for a BRAT is not a problem. Exspecially of you don’t plan on doing push ups. However adding 4 servos and brackets will add 12 ounces to the BRAT. This may be a problem if you are using 422 servos on the legs.
What if I am using 5645s on the legs? What “rules” are there to follow when picking out a servo? I remember that the ozin rating is the amount of oz the servo can handle at x inches (so for example if there is a 50ozin servo it can take 5oz 10inches away from the servo) Or something like that…
These CS-51 servos are about 50ozin at 6v if the interwebs is correct.
As with most complicated Physics scenarios, there’s ways to figure that out.
Usually, though, it comes down to people buying the best they can afford and finding out the hardway.
So… the rule of thumb in this case is to ask others what they think.
Methinks 5645’s will have no problems with an added 4DOF.
I’ve a 20DOF bot of entirley 5645’s, so that should give you an idea of how well they bear weight.
Keep in mind… my bot isn’t exactly agile, but it doesn’t fall over, either.
Just keep the battery weight to a minimum and in an unstressing place and you should do fine.
Hmmm, good point. If 5645s can be used to build a 20DOF humaniod why wouldn’t they support 4DOF of arms. My bad >.< didn’t realize it. In order to build the arms I am going to need to order more parts. Don’t exactly have a lot of money left. =
Didn’t know it at the time, but it proved to be a real POS. We switched to the HS-422 when we started noticing the trouble. The problem with the servo is the potentiometer IS the output bearing. So pressure added to the final gear was supported by the pot alone. It was ok for some apps, but real bad for others. If they work for you, then have a nice day. If they jitter or have trouble holding position, then use the control board to power other devices, or pitch it in the trash. 
However adding 4 servos and brackets will add 12 ounces to the BRAT. This may be a problem if you are using 422 servos on the legs. 
