I grew up with earthmovers and I have operated excavators for many years. My favorite machine is the hydraulic excavator. However, I changed jobs so I don't operate excavators anymore. Unfortunate, because I still regularly get itchy hands when I see these machines running. Unfortunately, buying a real excavator is not an option for me. Now there are remote controlled excavators for sale that run on model-hydraulics, but they cost a fortune. So there was only one thing to do, build one myself!
First i looked on the Internet if there were more people that had this idea. Sure enough, after some searching I found several videos and pictures of working RC excavators that did not cost thousands of dollars.
They were converted excavator models from "Bruder". Yes, childrens toys, but I must say that these models are very detailed. So i bought one and got to work.
Step 1: How it works
This excavator works with hacked servos
, that can spin indefinitely. These servos are connected to wooddrillbit thats running in an aluminum tube, with a steel pin in it which engages in the drill. This makes the turning movement from the servos to a Linair movement for the cylinders.
Step 2: Servo placement and controle
You could use the controllers that are in the servo's. There are allot of people that operate the excavator just with the hacked servo's. But i prefer the use of CTI controllers. They just give more smooth and faster movements.
So you have to replace the servo controllers for a CTI controllers.
You will need six hacked servo's in totall. Three for the boom, one for swinging and two for driving the tracks. In the pictures you can see how i placed the servo's in the boom.
You have to reinforce the boom with aluminium plates in serveral places, otherwise it will twist when you are digging.