SG90 mini robot arm S9 by FrN (Robot Arm for everyone!) by Francis128

Last crawled date: 3 years, 1 month ago

Here is a US10 dollars DIY mini-robot which designed for HK student. It uses the most common SG90 mini-servo motors and was powered by Ardurino Pro-mini or Nano.
Each servo have added a different step-down gear to increase the torque and reduce the speed to a reason manner.
Engineering Notes:
The waist servo have a speed reduction of 1:2 and 90 degree of rotation.
The upper arm servo have a speed reduction of 1:3 and 60 degree of rotation.
The lower arm servo have a speed reduction of 1:4 and 45 degree of rotation.
The base turning servo have a speed reduction of 1:5 and had extended the servo 5K VR from the servo in order to provide sufficient torque and 180 degree angle of rotation.
Six 4mm dia metal ball are required to support the base turning gear.
All servo motors are using the same gear of 9 teeth. This gear of 6 different tolerance/clearances are provided.
Enjoy!
Demo:https://www.youtube.com/watch?v=EqWLwB4PkA4
Where to buy?
20mm shaft: https://item.taobao.com/item.htm?spm=a1z09.2.0.0.38a12e8deTecbK&id=548322518504&_u=52bdisfs539b
90,180,360 degree SG90 servo: https://item.taobao.com/item.htm?spm=a1z09.2.0.0.36822e8d82V8ZH&id=39560573589&_u=52bdisfs41e7
4mm ball bearing: https://item.taobao.com/item.htm?spm=a1z09.2.0.0.36822e8d82V8ZH&id=549201779704&_u=52bdisfs8819