Ultrasonic Follower

This is a little stand for a phone or a device of your choosing that will use 2 Ultrasonic Sensors to try and follow you. It is inspired by this project: https://darwindelacruz.wordpress.com/2018/05/05/motion-tracking-robot-using-two-2-hc-s004-ultrasonic-sensor/

The project works by checking the distance from each sensor and if one of the sensors detects an object is close to it than the other it will rotate until they are equidistant.

Parts Needed:

• 1  Arduino Nano
• 2x HC-SR04 
• 1 28BYJ-48 5V Stepper Motor + ULN2003 Driver Board
• 9V Battery and battery clip
• Wires
• 3x M3x6 Bolts (optional - Used to screw down motor and tighten swivel onto motor shaft)

Programming the Arduino:

You will need the Arduino IDE installed to be able to program the Arduino,
Or if you would like I have made it available in the Arduino Web Editor as well.
https://create.arduino.cc/editor/dsk001785/cc647fd3-3af8-40c4-9955-fa9edc9e4fd9/preview

Adding Libraries:

One you have the IDE installed you will need to add the New Ping library to it so that the code compiles and has everything it needs.

You will go to Sketch > Include Library > Manage Library

You will search for New Ping and install (mine says update as I have it installed already)

Selecting Arduino Board:

Next select the correct board. Select Tools > Board > Arduino AVR Boards > Arduino Nano. Also change the Processor to ATmega328P (old bootloader)
You will also need to select the correct port, Once you plug in the Arduino with the USB cable the new port should appear as one of the options, select that one.

After that is done you should be able to load the Follower.ino and upload it to your Arduino.

Wiring:

DO NOT POWER THE STEPPER DRIVER THROUGH THE ARDUINO!!!!

Please wire the stepper driver like below directly to the battery. The driver can use too much current and burn out the Arduino, if you try and use the 5V pin.

Printing:

All parts should be in the correct orientation, when opened in the Slicer. You only need to print one of the swivel parts, depending on if you are willing to bend the pins on the Ultrasonic Sensor or not. (See assembly below) The only part that might need supports is the phone holder under the opening for threads, as long as you have good bridging. 

Assembly:

In my case I gently folded back the pins on the Ultrasonic sensors to have a cleaner look. But if you do not wish to do that there is a second version where you can install the sensors upside down and connect the wires to the top and not have to fold the pins at all. Use 2 of the M3 bolts to install the stepper motor and the other bolt is used like a set screw to hold the swivel onto the stepper motor shaft. The other components have their respective places. The Arduino is installed upside down and the 6 pins on the end of the Arduino that usually stick up are used to mount the Arduino, this gives it a solid mount and easy access to the pins.

Lastly slide the phone holder onto the swivel and screw in the knob to hold it in place. There is also a blank one provided in case anyone wanted to modify it to mount something else.