How to Build Project North Star Simplified Version

Introduction

On June 6th, Leap Motion open sourced an AR headset, “Project North Star.”

http://blog.leapmotion.com/north-star-open-source/

While a lot of exciting teaser movies came out, unfortunately most of the main parts are still not available.

At exiii, we did not stop there. By replacing with currently available parts in the market, we built a simplified version of Project North Star. Although the quality is not as good as the one we can see from the official movies, you can see and experience the possibility of this device.

In this blog post, we want to introduce how to build “Project North Star Simplified Version.”

License

Leap Motion open sourced Project North Star under Apache License 2.0. Project North Star Simplified Version also uses data open sourced under this license.

http://www.apache.org/licenses/LICENSE-2.0

We publish 3D data and document about Project North Star Simplified Version under CC BY 4.0. You can use these data under following condition.

https://creativecommons.org/licenses/by/4.0/

If you would like to use these data, please credit as follows:

CC BY 4.0, exiii Inc.

Overview

You can access the original mechanical guide of Project North Star from here.

https://leapmotion.github.io/ProjectNorthStar/mechanical.html

We changed followings for Simplified Version.

Leap Motion Controller

Leap Motion published 2 types of design data, data for the next generation model of Leap Motion Controller (LMC) and data for existing LMC. As we don’t have access to the next generation model yet, we used the latter.

3.5-inch 120Hz LCD

Although the original specifies VS035ZSM-NW0, it looks difficult to get this model. The maker of this display, BOE, only accepts large quantity order. After searching for substitutes, we found a 3.5-inch Raspberry Pi LCD which also includes driver circuits. Since it is also affordable, we decided to use this panel.

Display Driver

As the substitute panel above includes one, we simply decided to use it.

Reflectors

We CNC machined acrylic based on the 3D data Leap Motion provided.

Anti-Reflective Coating

The original seems to do 50-50% anti-reflective coating as acrylic transmit light as it is. We pasted window mirror film to get proper transmittance and reflectance.

OEM Headgear

The original suggests to use a welding headgear. As it’s affordable and comfortable to wear, it can be used for various headset-related projects, not just for Project North Star. The one specified by Leap Motion was not available from where we are located (Tokyo, Japan), we selected something similar.

Al Bar

Aluminum rail connecting the housing and headgear. It’s not impossible to get, but we decided to 3D print instead.

3D Printed Parts

We modified the data so that it can hold a new LCD and pass through HDMI and USB cables. While the original data used multiple types of screws, we made the headset buildable with just M2L6 self tap screws. Finally, we also made several modifications to strengthen the headset.

Parts List

Refer to the following gsheet for parts list. You can download the 3D data for each item from the URL.

https://docs.google.com/spreadsheets/d/17OPl2oNZefMu_XfwKp9CA5PygzD6_z3uMTJ1lndurGw/edit?usp=sharing

You can also download the necessary data from here.

https://drive.google.com/open?id=0B2oZ6b7iG9fWVkJybUYtYXV0V0E

If you want to see the assembled data, go to following.

https://a360.co/2NZxsos

How to Build

Polish the CNC machined acrylic with waterproof sandpaper. It looks like below before polishing.

Go from rough to fine so that you don’t see lines and patterns on the surface. As you finish with abrasive and paper towel, it should look like this. We went from 400 grit, 1000 grit, 1500 grit, and to abrasive.

Cut mirror film and make 8 of 20x80mm bands. Paste the films onto the inside of Reflector L/R.

It is not possible to perfectly align with bands next to each other, but keep going. Cut the areas sticking out from the Reflector’s edge. For the best results, we recommend to use a design knife.

Put Reflector into Reflector Holder, apply adhesive to the red circle, and fix the parts.

Put 3.5 inch LCD between LCD Holder A and B and screw together. Build 2 sets of the same thing.

Attach the LCD unit to Reflector Holder. Screw together at 6 points from the back.

Attach Reflector Holder to LCM Holder. Screw together at 5 points.

Connect a cable to Leap Motion Controller. Pass the cable through the hole first, and attach Leap Motion Controller to LMC Holder.

Attach Left Slide Rail and Right Slide Rail to Slider. Then screw to LMC Holder.

Attach Top Cover. Screw together at 2 points from the top.

Screw together at 4 points from the bottom.

Connect HDMI and USB cable to LCD.

Disassemble side dials of the headgear and remove parts like washers.

Put Slider in-between and tighten the dial again.

By adjusting the headgear to the stable position, it’s completed! We recommend using cable ties for better cable handling.

Setting Up

There are total 5 cables to connect: 2 of HDMI cables and 2 of USB cables from 3.5 inch LCD, and a USB cable from Leap Motion Controller. Connect all of them to PC. If you don’t have enough HDMI ports, use HDMI-Display port adopters.

Download Unity Package which Leap Motion made available.

Calibrate your device according to the following:

https://github.com/leapmotion/ProjectNorthStar/tree/master/Software

Summary

How was it? If you could successfully make it work or have any comments, please share on SNS with hashtags like #LeapMotion #ProjectNorthStar #exiii.

Leap Motion commented in their blog post, “by open sourcing the design and putting it into the hands of the hacker community, we hope to accelerate experimentation and discussion around what augmented reality can be.”

exiii really wanted to support this idea and made Simplified Version. We hope a lot of AR enthusiasts try building this headset and movement spread out.

Recruit

Project North Star showed us the future where physical world and virtual world naturally co-exist.

But in such environment, we believe that haptics is critical element for human-computer interaction.

If you are interested in building the future of computer interaction with haptics, please let us know! We have a lot of exciting projects coming up.

https://exiii.jp/recruit/