Stability or insanity
Tim Wescott presents a hands-on exploration of oscillator stability using a custom electromechanical pendulum. He converts a hard‑drive head actuator into a pendulum resonator, winds a 220‑ft #40 coil, and mounts the assembly on low‑friction ball bearings before integrating it into an electronic oscillator. Iteration and careful modeling—treating the pendulum as a resonator and including coil inductance in the circuit—prove essential to obtain sustained oscillation. The resulting prototype functions as an intentionally inaccurate electro‑mechanical clock driven by a "tick‑toc" circuit that minimizes load to preserve a high loaded Q and requires manual start to demonstrate a hard limit cycle. The project highlights practical tradeoffs between stability, Q, and the realities of prototyping.
Data Types for Control & DSP
Control engineers often default to double precision, but Tim Wescott shows that choice can waste CPU cycles on embedded targets. He separates numeric representation into floating point, integer, and fixed-point, then walks through the tradeoffs, including quantization, overflow, and performance. A concrete PID example highlights why integrator precision and ADC scaling should drive your choice of data type rather than habit.
PID Without a PhD
You do not need control theory to implement useful PID loops in embedded projects. Tim Wescott walks through simple, ready-to-use C code, clear explanations of P, I and D terms, and a practical tuning recipe you can apply to motors, precision actuators, and heaters. The article highlights anti-windup, sampling-rate guidance, and when to call in a control expert.
Levitating Globe Teardown, Part 2
Tim Wescott opens up a budget levitating globe and shows why it seems magical: a massive 30 mm rare-earth magnet and a deliberately cheap magnetic circuit. He documents a bolt used as the flux core, a likely microcontroller and hall sensor in the head, very fine winding in the electromagnet, and a single-transistor unidirectional drive. Part 3 will measure forces and sensor voltages to build a better controller.
Levitating Globe Teardown, Part 1
Tim Wescott buys a $30 floating-globe desk toy and walks through first impressions, hands-on magnet experiments, and a frank critique of its control system. He highlights the toy's underdamped response, uni-polar electromagnet tradeoffs, and simple hacks that reveal clues about the pole pieces and magnet layout. This is a practical, engineer-forward preview before the actual teardown in part two.
PID Without a PhD
You do not need control theory to implement useful PID loops in embedded projects. Tim Wescott walks through simple, ready-to-use C code, clear explanations of P, I and D terms, and a practical tuning recipe you can apply to motors, precision actuators, and heaters. The article highlights anti-windup, sampling-rate guidance, and when to call in a control expert.
Levitating Globe Teardown, Part 1
Tim Wescott buys a $30 floating-globe desk toy and walks through first impressions, hands-on magnet experiments, and a frank critique of its control system. He highlights the toy's underdamped response, uni-polar electromagnet tradeoffs, and simple hacks that reveal clues about the pole pieces and magnet layout. This is a practical, engineer-forward preview before the actual teardown in part two.
Data Types for Control & DSP
Control engineers often default to double precision, but Tim Wescott shows that choice can waste CPU cycles on embedded targets. He separates numeric representation into floating point, integer, and fixed-point, then walks through the tradeoffs, including quantization, overflow, and performance. A concrete PID example highlights why integrator precision and ADC scaling should drive your choice of data type rather than habit.
Levitating Globe Teardown, Part 2
Tim Wescott opens up a budget levitating globe and shows why it seems magical: a massive 30 mm rare-earth magnet and a deliberately cheap magnetic circuit. He documents a bolt used as the flux core, a likely microcontroller and hall sensor in the head, very fine winding in the electromagnet, and a single-transistor unidirectional drive. Part 3 will measure forces and sensor voltages to build a better controller.
Stability or insanity
Tim Wescott presents a hands-on exploration of oscillator stability using a custom electromechanical pendulum. He converts a hard‑drive head actuator into a pendulum resonator, winds a 220‑ft #40 coil, and mounts the assembly on low‑friction ball bearings before integrating it into an electronic oscillator. Iteration and careful modeling—treating the pendulum as a resonator and including coil inductance in the circuit—prove essential to obtain sustained oscillation. The resulting prototype functions as an intentionally inaccurate electro‑mechanical clock driven by a "tick‑toc" circuit that minimizes load to preserve a high loaded Q and requires manual start to demonstrate a hard limit cycle. The project highlights practical tradeoffs between stability, Q, and the realities of prototyping.
PID Without a PhD
You do not need control theory to implement useful PID loops in embedded projects. Tim Wescott walks through simple, ready-to-use C code, clear explanations of P, I and D terms, and a practical tuning recipe you can apply to motors, precision actuators, and heaters. The article highlights anti-windup, sampling-rate guidance, and when to call in a control expert.
Levitating Globe Teardown, Part 1
Tim Wescott buys a $30 floating-globe desk toy and walks through first impressions, hands-on magnet experiments, and a frank critique of its control system. He highlights the toy's underdamped response, uni-polar electromagnet tradeoffs, and simple hacks that reveal clues about the pole pieces and magnet layout. This is a practical, engineer-forward preview before the actual teardown in part two.
Levitating Globe Teardown, Part 2
Tim Wescott opens up a budget levitating globe and shows why it seems magical: a massive 30 mm rare-earth magnet and a deliberately cheap magnetic circuit. He documents a bolt used as the flux core, a likely microcontroller and hall sensor in the head, very fine winding in the electromagnet, and a single-transistor unidirectional drive. Part 3 will measure forces and sensor voltages to build a better controller.
Data Types for Control & DSP
Control engineers often default to double precision, but Tim Wescott shows that choice can waste CPU cycles on embedded targets. He separates numeric representation into floating point, integer, and fixed-point, then walks through the tradeoffs, including quantization, overflow, and performance. A concrete PID example highlights why integrator precision and ADC scaling should drive your choice of data type rather than habit.
Stability or insanity
Tim Wescott presents a hands-on exploration of oscillator stability using a custom electromechanical pendulum. He converts a hard‑drive head actuator into a pendulum resonator, winds a 220‑ft #40 coil, and mounts the assembly on low‑friction ball bearings before integrating it into an electronic oscillator. Iteration and careful modeling—treating the pendulum as a resonator and including coil inductance in the circuit—prove essential to obtain sustained oscillation. The resulting prototype functions as an intentionally inaccurate electro‑mechanical clock driven by a "tick‑toc" circuit that minimizes load to preserve a high loaded Q and requires manual start to demonstrate a hard limit cycle. The project highlights practical tradeoffs between stability, Q, and the realities of prototyping.
