Circuit Design Assistance

I plan to use NRF52840

I need a circuit that would use wire wrapped around spark plug lead to sense spark impulses and return number of them via I2C

rambros

Hey, could you help me to design a cirquit?

rambros

I plan to transmit the number with those RPMs over BLE, please use proper noise reduction techniques to improve BLE transmissions

Thought

flux

I'd be happy to help design your circuit! To get started, I'll need to ask just one key question:

Question 1:
What is the primary function of the circuit you want to design? For example, is it for signal amplification, filtering, power regulation, oscillation, or something else?

Feel free to provide any specific requirements or details, or let me know if you'd like me to make a reasonable assumption.

Thought

flux

Great choice with the NRF52840. To further refine the design, I have one additional question:

Question 2:
Do you require electrical isolation (e.g., using an optocoupler) between the spark-sensing element and the MCU for safety and signal integrity, or should the sensor interface couple directly to the NRF52840?

Feel free to provide any specific details or let me know if you'd like me to suggest a standard approach.

Direct interface

Use optocoupler isolation

Direct coupling initially

Files

Schematic

Layout

3D View

Schematic of [2-layer] JLCPCB Constraints

Resistance

500 Ω

Capacitance

100uF

Inductance

1uH

[2-layer] JLCPCB Constraints