What is ARPen?

Ever wanted to 3d print a dock for your phone? Or maybe a coffee cup holder that can be attached next to your car dashboard? If so, you would have to measure the dimensions of your phone and dashboard, construct 3d models using CAD-like software, convert these models to appropriate format, and print them in 3d. As you can see, this is an arduous process.

ARPen is an iOS app that allows you to use a mobile pen to perform free-hand 3D modeling directly in the real world. The app uses the in-built iPhone camera to do the tracking. ARPen uses the ARKit framework to track a special 3D-printed pen, called ARPen, in 3D. Instructions to build this pen can be found below.

This project is sponsored by the German Federal Ministry of Education and Research (BMBF) as part of their Open Photonics call (Personal Photonics, 13N14065).

Instructions

1. Building the ARPen

You can 3D print the whole ARPen on your own. The 3d models can be found under the ARPen 3d Models and Marker folder.

1. Print the 3d models for the ARPen.
   • If you are using a multi-material printer, which allows you to use more than one print material, print the following models
     • Pen.stl in black or white color.
     • Box_white.stl in white color and Box_black.stl in black color. Note: These two models may need to be merged before printing using appropriate software.
     • Cap_white.stl in white color and Cap_black.stl in black color. Note: These two models may need to be merged before printing using appropriate software.
   • If you are using a single-material printer:
     • Print these models: Pen.stl, Box.stl, and Cap.stl.
     • Print Sticker.pdf on an A4 paper using a normal 2D printer, cut out the individual marker codes (6x), and paste them around the printed box.
2. Insert three momentary switches or buttons into the holes in the ARPen as shown below and solder them to cables, which will be connected to a Bluetooth chip as described in step 4.
   
3. Glue the box to the pen.
4. Add the Arduino Sketch under ARPen/Bluetooth Software to a Bluetooth chip. We used RedBear BLE Nano v2. To add the Arduino Sketch to the RedBear BLE Nano v2, please follow the instructions here.
   • Note: RedBear has been acquired by Particle Mesh and is currently not available for sale. It is expected to be available for purchase on the Particle Mesh catalog soon.
   • Make sure that the BLE chip is inserted into the loader as shown in below -- inserting it the other way would cause the BLE chip to heat up and won't allow you to load your Arduino Sketch to the BLE chip.
5. Connect the Bluetooth chip and lithium-ion battery (110 mAh, 3.5V, link to a sample battery) to the momentary buttons as shown below.
   
6. Place the chip and battery inside the box, and then glue the pen to the box.

2. Using the iOS App

You can build the ARPen iOS app like every other iOS project.

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Interested in Contributing to ARPen?

Feel free to submit pull requests, create issues or spread the word. Also take a look at our developer guide.