Joel Diccion’s Work Log

Joel Diccion’s Work Log

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  • Post last modified:April 27, 2024
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  • Post category:Work Logs

Tesla Coil (Spring 2024)

Work Log 1 (1/21/2024 – 1/27/2024)

Personal To-Do list for the week:

  • Become familiar with the analog portion of the drive circuit
  • Design a single-layer board for the drive circuit in KiCad using available component footprints
  • Prepare for group discussion on the integration of our three subsystems
  • Design a Faraday cage to enclose the secondary circuit

The following sketch is what an ideal final product may look like. The control unit has three subsystems, the digital controller, interrupter, and drive circuit.

Work Log 5 (2/18/2024 – 2/24/2024)

Accomplished this week:

  • Chose feedback topography
  • Constructed prototype driver circuit
  • Validated prototype driver circuit function using expected inputs

It was observed that a sinusoidal feedback signal causes the duty cycle of the resonating signal to stray significantly from 50%. As such, the final circuit will utilize two logic inverters in series in order to modify the sinusoid into a square wave of equal frequency (precise amplitude feedback is not necessary).

The images below detail the findings in the previous paragraph. The yellow signal is the simulated feedback from the Tesla coil, and the green signal is the output to the gate drive transformer.

Work Log 6 (3/3/2024 – 3/9/2024)

Accomplished this week:

  • Determined method to have direct drive of the Tesla coil using an analog audio input.

Goals for this week:

  • Prototype analog driver circuit in simulation.
  • Construct physical circuit on a breadboard and validate with expected inputs.

Work Log 9 (3/24/2024 – 3/30/2024)

This week we attempted to connect the Arduino nano to the driver circuit, but we ran into a problem. I probed the enable pin of the driver circuit to make sure the voltage is compatible and found the enable pin to be at 12V. This would damage the nano as it can only handle VCC+-0.5V, where VCC is 5 volts in our circuit. As such, a logic-level converter will need to be added to the circuit. I believe this can done with a simple BJT circuit, since the enable pin only needs to be pulled down to ground, and will pull itself up to 12V. Developing this circuit will be the goal of next week.

Work Log 10 (3/31/2024 – 4/6/2024)

Some BJT’s in the lab were found to be appropriate for the logic-level converter application, so no new parts needed to be ordered. The circuit was prototyped with theoretical inputs and was found to be effective at pulling the enable pin of the driver circuit to ground without subjecting the input signal to high voltages. For next week, my goal is to combine this with the rest of the driver circuit on a prototype board to integrate it with the rest of the tesla coil systems.

Work Log 11 (4/7/2024 – 4/13/2024)

With final subsystem integration imminent, it was time to design and build the enclosure. Design of the enclosure was designed to use as many of the 3D printed parts we already had as possible to save time. Below is the final CAD render.

Work Log 12 (4/14/2024 – 4/27/2024)

This work log includes work from finals week as the project bled over. For the final week

The breadboard driver circuit continues to operate as expected, but extra electrical noise and difficulty with form factor are sufficient reasons to justify moving the driver circuit to a Protoboard. Due to the relative complexity of the circuit, and the numerous modifications made from the base schematic, I decided to make a new schematic in KiCad for clarity. This also allowed me to find the optimal component layout for protoboard integration.

With these KiCad documents, soldering began. The resulting protoboard was verified similarly to the breadboard circuit, and all outputs worked as expected. One revision that was made was to invert the input logic signal so the Tesla Coil would be off when the Arduino is off, otherwise the Coil would be on all the time if the Arduino is disconnected. This inversion was achieved by using the extra inverters on the 74HC14 chip before feeding the signal to the PN2222A for amplification. The final board is below:

Finally, the Tesla coil was assembled with the printed parts from Work Log 11 and the other’s subsystems.

Tesla Coil (Fall 2023)

Work Log 1 (Week of 9/18/2023)

Over the past week, we have successfully determined the initial sizing for our secondary circuit. The bulk of the work has been on the sizing of components in order to maximize safety and audio reproduction characteristics. After the secondary circuit has been tuned, the values can be used to determine the tuning of the primary circuit to maximize the efficiency of the energy transfer. Parts have been ordered for the windings of the primary and secondary circuits.

Our main goal for the next week is to assemble and tune the secondary circuit ASAP, then we can choose components for the primary circuit.

Work Log 3 (Week of 10/23/2023)

I successfully acquired and scaled CAD files for the semiautomatic coil winding machine. Printing is ready to commence over the next week, and the secondary coil can finally be wound. This, combined with work in parallel on the driver circuity, will ensure we are making progress towards a functioning tesla coil.

Work Log 4 (Week of 10/30/2023)

Accomplished:

  • Printed and assembled parts for semiautomatic coil winder (See attached image).
  • Reviewed BOM for digikey order.

Immediate Goals:

  • Wind secondary circuit inductor
  • Assemble secondary circuit
  • CAD frame for the primary circuit and attachment for the secondary circuit