I'm currently working on a robot spider which would walk thanks to servo motors.
I'm using an Arduino Uno card with a mini-maestro 18 microcontroller
So i've plugged all of the componements, put the working program into the arduino but nothing happens and also I put 8V in the maestro, it started to smoke a bit.
That is a pretty picture but it is not of much use, schematics are far better and easier to read. It would help if you posted links to the technical data on the hardware you used. I am not going to burn a lot of time looking up the parts. You might reread the data sheets and plan on purchasing another board, when smoke comes out the board is damaged and will fail, we just do not know when.