Wireless Range Finder Servo

Guide Updated: November 23rd 2018

About the Project

Servo kit

When I completed my kit I started looking into mods and such to make it seems more real. I saw a few wireless servo kits but they all were bulky, expensive, or just not what I wanted. I decided to make my own.

I spent a couple weeks prototyping and finding the right parts. Finding a small yet powerful servo was difficult as micro servos are far too weak. I ended up settling on a low profile servo. Attaching this to two mini computers with custom software on it I was able to make a controllable servo utilizing small 433mhz transmission chips. I tracked down some as-close-as-possible accurate buttons from Boba Fett's gauntlets so the kit doesn't look out of place. These buttons are the alco switches on the right gauntlet and the push buttons on the ROTJ left gauntlet.

Each module is on a custom built PCB board. The receiver is inside a custom 3D printed box to keep it free of moisture and sweat. The transmitter is inside a large heat shrink wrap to make sure nothing makes contact with the electronics but still keeps it small enough to fit most places.

Notes Before Proceeding

  • This kit may not work if you have a particularly heavy rangefinder stalk and/or topper.
  • Test the servo before mounting to take note of how the servo rotates (such as which way is up and down).
  • If you servo ever gets 'out of sync', detach it from the rangefinder stalk and power cycle it. Turning on the servo will always set it to the 'up' position.
  • If the given servo extensions don't work for your situation, try these:¬†https://www.servocity.com/servo-rotary-driver¬†
  • The wires coming out of the two modules are antennas, adjust them as needed.

Included In The Kit

  • Receiver module with attached servo (in 3D printed box)
  • Transmitter module with attached button (in heat shrink)
  • 2x Servo shaft extensions (3d printed)
    • Note: These are printed so that you can shorten them if needed. Two are included as a backup.
  • 4x Curved servo mounts (3d printed)
  • 2x Flat servo mounts (3d printed)
    • Cut, dremel, and sand parts away to shape it to your helmet.

Suggestions Before Installation

Ear Cap Magnets

Being able to remove the rangefinder stalk will be very advantageous to this kit. If anything ever becomes misaligned you can remove the rangefinder stalk and reboot the servo system. Doing this will set the servo in the 'up' position.

The easiest way to achieve this option is to make your ear cap magnetic (An alternative is to make your server removable). Pictured to the right is how I have my magnets set up. I use two large rare-earth magnets and a small one. This keeps the ear cap securely in place.

Ear cap magnet locations


Drill a 3/8th inch hole in the dead center of your ear where the stalk ends. This will be where the servo will attach so make sure it is center.
This hole should go all the way though into the inside of your helmet. The hole should be marginally larger than 3/8th to ensure the servo extension has enough room to rotate, just rotate the drill around to give it a little extra room. Test to make sure one of the included servo extension fit well.

Helmet hear

Mount the Servo
With the hole drilled you should mount the servo next. This part can be tricky.
The servo will generally be mounted with the longer edge facing the front of the helmet (see below image).
You have to mount the servo with the gear head exactly in the middle of the hole, running parallel with the ear cap, and perpendicular with the rangefinder stalk. The servo extension piece needs to come from the servo to the stalk in a perfectly straight manner as to not cause stress on the servo and/or twist and turn things in way they are not meant to (see right image). Notice in the image where the gear head is.

Perfectly center and level the servo with the hole you drilled.

Gear head

Included in your kit are several mounts. They are all 3d printed. The curved ones are all generic and could fit your helmet with minimal effort. The other two mounts are flat. They are printed at a higher infill to give you the ability to cut and dremel them to the curvature of your helmet. Pick and modify which one works best for you.
Remember the servo mounts horizontally with the longer edge facing out and runs straight across (see image to right).

Servo Extension
Contained in your kit are two 3D printed extensions. They are both the same and both are printed. I give you two because you may need to cut/trim it, so you get one as a backup. Make sure when cutting it that you don't cut off the side with the gear teeth.
Insert the extension onto the servo and do a test run to make sure it rotates 90 degrees correctly. Make adjustments if necessary.
Now attach the extension to the rangefinder stalk however you wish. Make sure you mount it in the correct orientation as the servo (mount it pointing up or down depending on the servo state). If you chose the magnetic earcap route you could ignore this precaution as you can just remove the stalk, reset the servo to the up position, and reinsert.

To mount my stalk I drilled a 3/8th hole into the center base of the stalk and inserted the extension into that hole. I put plenty of superglue with 'Bob Smith Industries Insta-Set' to ensure a quick strong hold.

Servo extension attached

Final Thoughts

Hopefully you have been able to get it mounted in your helmet. If you still need assistance reach out and I can help how I can.

To operate properly, turn on the receiver module (servo). Wait for the servo make noise and possibly move. This means it is setting its default position. Now turn on the transmitter module (button). Give the system a second to start up. Pressing the button before everything has initialized may make the servo act unexpectedly for a moment.

If the kit stops working start by checking the batteries. If the batteries get low enough the kit will not work as expected.

If your servo ever becomes disconnected the yellow wire is the data cable, marked with a "D" on the board. Re-connect it to the three pins with the yellow wire on the left.

Be cautious with the servo. Do not force it to do something it shouldn't be doing. If you strip a gear or thread it will result in unwanted motions.
When transporting the helmet I prefer to remove the rangefinder stalk and reinsert it when I arrive on location. This prevents it from being bumped around and forcefully moved.

If the rangefinder manually gets moved and the servo doesn't notice, or the rangefinder gets attached incorrectly at start up, the servo will get out of sync. Remove the rangefinder and power cycle the system. This will reset the servo to the 'up' position.

The wires coming out of the two modules are antennas, adjust them as needed.

completed servo


My name is Brandon Owens, 501st Member BH/DZ-51512 and MMCC OM#1793. I have an approved Tusken Raider (ANH) and a Boba Fett (ROTJ) that I spend years researching and building. I'm here to share my progress, methods, and findings.