Low-Power Electromagnetic Coilgun:

This is a science/STEM project that uses mainly physics, electronics, and programming to accelerate a projectile with the power of electromagnetism, the same forces that move maglev trains and create sound in your phone speaker, like a temporary magnet. One of the goals was to create it so it would be accessible to build, to potentially increase STEM education opportunities. This was kept in mind throughout the project, making the design accessible and relatively simple.

This time lapse shows most of the coil winding process.

It took roughly just over 2 hours to wind both coils, each with 5 full compacted layers and a 6th layer for the rest of the magnet wire. Each layer was secured with electrical tape. The enameled magnet wire was 0.6mm in diameter and 10 metres in length for each coil.

I made it on the free app Fritzing. The battery represents the power input and the solenoid represents the coils. For my final product, I put the high current part of the circuit (transistor part) on a separate perfboard, as a breadboard is unsuitable for high current applications.

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Some information is on the presentation, but here are some of the basic features:

- MOSFET transistor for the coils

- freewheeling/flyback diode on coils (to stop voltage spikes)

- pull down resistor for transistor and switches (to avoid false presses)

- CNY70 optical sensor (for detecting projectile)

- hardware sensor adjusting (trimmer potentiometer)

- safety switch

Here is the table I made to compare which transistor to use. I ended not going for the most suitable one, as I already had another transistor from the table that was sufficient for the task. The information was taken from the datasheet.