Boba Fett helmet arm - build guidance

Support
1

Hi,
I am a beginner and hoping to make this Boba Fett helmet sight arm move at the touch of a button :)

The aim is to push a button = arm moves down 90deg and stops / push button again = arm moves up 90deg and stops.

I have some parts at the moment (hopefully correct but others may be needed), as on the image.

Please let me know where I can find out how to connect all the hardware:

  1. Connect motor driver board (SparkFun TB6612FNG) to the pico board.
  2. Connect motor (12V / 18RPM) to motor driver board.
  3. Where to connect the start stop push switch.
  4. Where to connect the 2 limit switches (for the end of the up/down arm travel).

(The battery I have is a lipo 18650, 3.7V)

Many thanks in advance, any help much appreciated.

03
032073×1165 439 KB

2

How are you going to drive the 12V motor with a 3.7 V Battery?
How heavy is the arm?
IMHO, a servo may be a better and easier option.

EDIT: Forgot to say, really nice project. =)

3

Thanks for the comments - yes good point, a servo would probably be ok instead.

The arm weighs 73g. Would need at least 0.11 N-m (1.12 kg-cm) torque to rotate it up from horizontal. So I will look into using a low profile servo instead - I guess the speed of rotation can be adjusted with the pico board?
And sounds like with the servo it will stop when stalled at the stop positions at horizontal and vertical, so limit switches probably not needed :) . will have a look into it…

4

You can get high torque servos, if need be. And ones with metal gears for added strength. I have Pi and Pico servo setups here at home. On the Pi side I use Pan Tilt Hats, and on the Pico side I have an Inventor 2040. Both of these have dedicated servo controllers built in. It saves you from having to mess with PWM, Pulse Width Modulation. I can move the servos to a specific positions.