Electromagnetic Accelerator Ring

Personal Project

Project Outline

The goal of this project was to build an interactive accelerator loop that would use solenoids to accelerate metal objects around a circular track as an interesting desk toy and demonstration for my brother's high school physics classroom.

Final Build

Final REnder

Operation Video

Design Features

Actuators

4 custom wound solenoids

Sensors

4 light break sensors built from IR LED's and phototransistors

Interface

I2C Display Screen
4 Buttons for menu navigation and operation
4 Status LED's
Rocker switch for power and emergency stop

Power and Control

Arduino Mega
Wall adapter and DC power jack

Operation

Operation is split into multiple different modes which are accessible through a custom programmed menu.

Sense Mode

When the light break sensor reading is greater than a set distance from the default calibrated value, the solenoid will be on.

Manual Mode

When a button is pushed by the user, the corresponding solenoid will turn on.

Game Mode

If a light break sensor is triggered and the corresponding button is pressed at the same time, the solenoid will turn on. A successful activation will add to the users score while missing the button as a ball passes through each sensor will reset the score to zero. High score is saved in EEPROM and displayed.

Delay Mode

The solenoid will activate while the light break sensor is broken as well as for a user defined period of time afterwards. The amount of time the solenoid stays on afterwards can be changed using the buttons with left/right buttons providing fine control and up/down buttons providing course control.

Trigger Mode

The solenoid will activate for a set period of time immediately when the light break sensor is broken. The amount of time the solenoid stays on afterwards can be changed using the buttons with left/right buttons providing fine control and up/down buttons providing course control.

Recalibrate

A debug mode that will show live values of each sensor and the calibrated values. The down button can be pressed at any time to set the current sensor readings as the new calibrated values. Calibrated values are stored in EEPROM for future access.

Safety Features

Current is limited to 10A and each solenoid takes ~5A to activate, so the program ensures no more than two solenoids are ever active.
Solenoids will deactivate after two seconds to prevent a solenoid staying on due to a sensor breaking or an object getting stuck. This helps mitigate coil overheating.
After 5 minutes of continuous running in any mode the accelerator will reset back to the main menu to prevent being left on and potentially overheating.