Quantity   Component name
2 × Servo SG90 Cheapest and smallest I could find
1 × Arduino UNO I had these laying around, but for the final version I'll change it for a Nano or another smaller and cheaper board
5 × Buttons One for each tool + one to extend/retract the tools
2 × Limit switch As the servos can't do 360 degrees and aren't precise, just used two of this to check that the tool is properly aligned with the hole