Motion Sensor Activated Space Anchor

The "Space Anchor" is a part of the video game Honkai: Star Rail that is used to transport the player around the game and restore HP. When the player comes near it, it lights up and lets out a sound. In this project I tried to recreate this game part with a combination of CAD and electronics.

I got an Arduino Starter Kit from Amazon which contained all the hardware I needed.

Hardware:

1. Breadboard
2. Blue LEDs
3. 220k and 10k resistors
4. Arduino UNO
5. Jumper wires
6. Phototransistor
7. Potentiometer

Software:

1. Arduino IDE
2. Fusion 360

Printing:

1. 3D Printer (Any should work, I used the Prusa MK4)
2. Blue and Brown PLA Filament

To start off, you can CAD the space anchor so it can be 3D printed.

Open a new file in Fusion set in mm and upload the first picture on this step as a canvas to be used as a template. Calibrate the image so the top side is 100mm long.

Make a torus centered about the origin with a diameter of 5mm. Then, move it so it matches the position of the rings in the image. It should be a combination of different angling and translation. Once you have the first ring set, you can duplicate that ring for the second inner ring and follow the same process.

For the larger rings follow the same process but the torus has a diameter of 10mm.

Now the rings are done with construction, you just need to add an appearance. The best appearance I found is the Matte Brass found in the fusion appearance library, but I ended up printing in a simple brown so this is more of an extra step.

Now you are done with the rings!

Start off with making a loose point spline with a similar shape to the bottom pieces, but only do half of a piece. Since the shapes are not symmetric it will be a little bit off from the game, but it should be mostly correct. Once the splines are completed you can revolve it through the center line of the sketch. For the appearance try to change the basic steel appearance into a blue that is closer to the image. When I 3d printed the project I did it in a basic blue, so the appearance in CAD does not matter too much.

You're halfway done with the CAD now!

The center piece of the CAD is in fragments, so to make it easier you can start off with a sphere. It should have a diameter of 20mm. Then, construct offset planes to the sphere and draw sketches on the plane in the shape of shards. Once done, emboss these shards onto the sphere. This process should be completed multiple times around the sphere with variety to make it more realistic. When embossing make sure to vary the length of extrusion from 1mm to 2mm.

Now you're ready to print!

I separated the STL files per color to make it easier to print. If you would like the CAD to be bigger you can scale it larger in your slicing software, but this was the size I preferred.

Attach your Arduino UNO to the breadboard with the appropriate wires.

Start off with getting 3 blue LEDs and place them in the middle of the bread board. The anode of the LED should be connected to a digital pin (9,10,11) with a jumper wire, and the cathode connected to a 220k resistor. Next, place the phototransistor further down the board, with the emitter connected to the 5V and the collector connected to a 10k resistor and jumper wire connecting it to GND.

For the LCD, start off with connecting the VSS, E, LED- to GND and VDD, LED+ to 5V. Place the potentiometer at the top of the bread board, and have the V0 connect to the middle pin of it. The other two pins should be connected to 5V and GND. The RS, R/W, DB4, DB5, DB6, DB7 should connect to the 2, 3, 4, 5, 6, 7 digital pins. Make sure when wiring everything to not cover the phototransistor or the LEDs.

I have attached the code the Arduino will run on to light up and show the message on the LCD. If the LCD is on but no text is being displayed make sure the contrast is high enough by adjusting the potentiometer. Otherwise, the light might need to be recalibrated to better be sensitive to the average lighting in the room. To do this change the "const int DARK_THRESHOLD = 200;" line based on what the serial monitor displays as the average light without covering the phototransistor.

The LCD should be facing the person, with the LEDs behind it and CAD on the Arduino. To make the CAD stick upright you can tape it down or wrap the wires around it. When a person comes near, covering the phototransistor, the LEDs should turn on like the game mechanics. That's it!!!