Below is a quick sketch of a possible craft stick arm keeping some of the servo weight off the arm. Larger servos would be located near the base and a micro servo at the elbow that would actuate the gripper via a rod or pull string.
I like it!
It does look like it could be more complicated to drive. Don’t you have to add the angle of the shoulder to the angle of the elbow (knee?) ? Something like that.
Alan KM6VV
I’m rebuilding the whole arm. I have some really light weight carbon fiber rods, about as thick as the graphite core inside a common pencil.
I just placed an order for 2 nice strong standard servos that Zoomkat linked me to.
2 of these
hobbypartz.com/kahaoubrmo14.html
Those will make up the base of the arm.
I’m going to use that push rod style that you guys just sketched up.
Since i’ll have a couple stronger base servos, i’ll be able to add a wrist rotation servo as well.
The pan/tilt sholder servos at the base will be really strong, with so much strength, i won’t have to worry about stressing the micro servos.
Since the elbow’s micro servo will be near the base, using the style that Zoomkat just displayed, that should create a bit of stability.
There isn’t a lot i can do about wrist rotation besides having a direct servo on it, but i MAY be able to rig up a cabled gripper servo. But i may not, since i really like how my gripper came out. It performs excellently, it can easily grab a tiny screw or even something as large as a 9 volt battery.
Just ordered a high quality class 1 usb bluetooth dongle from newegg too, so my robot will once again be fully wireless.
Thanks guys, this is turning out really nice. I’m really getting things together. Especially since my programming had gotten A LOT better.
Have all new servos, Was unable to use the push rod idea, i simply didn’t have the parts needed. I got the ball bearings and all that stuff, but no way to attach them. I just didn’t have the precision tools required for the task. But the arm is much nicer now.
New arm looks much like the old one, but now has wrist-rotate. Another nice feature is the new elbow servo is a tower-pro MG90 2.2kg/cm micro servo!
The strength of the elbow servo makes the arm much stronger. It’s able to lift a fully loaded keychain.
Further more the sholder servos the pan/tilt base is strong enough to lift the robot off the ground. My robot can literally do pushups.
Only problem now, my 5v 1.5A regulator is starting to pump out some heat, even with it’s fancy heatsink.
I have a new bluetooth dongle for my PC, but then my Bluetooth UART adapter went ka-poot. So i need to order one later this week.
Which i will hopefully be able to show in the next day or two. Boyfriend is coming over with a better camera, eventually.
So any pictures, it’ll be wired to a laptop.
-sigh- i really hope i don’t have to use a fan on the regulator again. That fan really drains the battery. Going to try a much larger heatsink.