Source: https://mokxi.com/learn/path/servo-and-actuators Updated: 2026-11-11 All paths # Servos, solenoids and actuators Everything that moves a thing to a place: servo pulses measured and calibrated, big servos and their supply, easing curves, solenoids with a flyback diode, linear actuators, vibration motors, and an animatronic face on a PCA9685. Arduino Uno R3 Free 7 lessons 6 h 4 chapters 2,011 XP Robotics · Intermediate +150 XP 0 of 7 done Start the course free Servo pulses: measure, predict, calibrate Lesson plan for teachers What you will build ## 2 projects, built step by step 7 lessons in 4 chapters, about 6 hours on a simulated Arduino Uno R3. Free, in your browser, every step checked by the simulator. Chapter 1 project ### Easing: motion that looks alive The same servo move three ways: linear, smoothstep and ease-out-back. Predict where each curve puts the horn at a quarter of the time, then make the move slower. Open it in the simulator Chapter 2 project ### Linear actuators and end stops A 12 V linear actuator on an L298N. Drive it to its end switches, place it by the clock alone, and see dead reckoning come up short the moment the load changes. Open it in the simulator The map ## Chapter by chapter Each lesson opens when the one before it is done, and each chapter ends in a project. Chapter 1 ## Servos for real Pulse widths you can predict, a window you can calibrate, a big servo’s supply, and motion that eases. Open 236 XP ### Servo pulses: measure, predict, calibrate Send a servo any pulse width you like from the Serial Monitor, predict the angle before you press Enter, read the current it draws while it moves, and calibrate for a servo with a different window. 0 of 6 steps Start What is in it Locked 200 XP ### Big servos: the amps are the hard part An MG996R metal-gear servo on its own 6 V pack. The same pulses as an SG90, but a supply that has to give amps, a speed that falls with the voltage, and a servo that gives up below 4 V. 0 of 6 steps Project Locked 436 XP ### Easing: motion that looks alive The same servo move three ways: linear, smoothstep and ease-out-back. Predict where each curve puts the horn at a quarter of the time, then make the move slower. 0 of 6 steps Chapter 2 ## Push and pull A solenoid and the diode that saves its MOSFET, and a linear actuator placed by the clock. Locked 218 XP ### Solenoids and the flyback diode A 12 V push-pull solenoid on a logic-level MOSFET. Predict the coil current from Ohm’s law, watch the diode carry the kick when the MOSFET lets go, and tap faster. 0 of 6 steps Project Locked 436 XP ### Linear actuators and end stops A 12 V linear actuator on an L298N. Drive it to its end switches, place it by the clock alone, and see dead reckoning come up short the moment the load changes. 0 of 6 steps Chapter 3 ## Feel it A coin vibration motor: its start voltage, a kick-start, and patterns that carry meaning. Locked 236 XP ### Vibration motors: haptics A coin vibration motor on a 2N2222. Predict its current, find the duty where it will not start, kick-start it, and play and tune haptic patterns. 0 of 6 steps Chapter 4 ## Boss build An animatronic face on a PCA9685 with moods, blinks, glances and a jaw that talks. Locked 249 XP ### Boss: an animatronic face Eyes, eyelids, brows and a jaw on four servos through a PCA9685. Moods from a table, blinks and glances on millis(), a talk command, and a face you make your own. 0 of 7 steps Syllabus ## Every lesson in the course All 7 lessons, in order, each with what it covers. Any of them opens in the editor right away. Chapter 1 ### Servos for real - Servo pulses: measure, predict, calibrate Send a servo any pulse width you like from the Serial Monitor, predict the angle before you press Enter, read the current it draws while it moves, and calibrate for a servo with a different window. - Big servos: the amps are the hard part An MG996R metal-gear servo on its own 6 V pack. The same pulses as an SG90, but a supply that has to give amps, a speed that falls with the voltage, and a servo that gives up below 4 V. - Easing: motion that looks alive The same servo move three ways: linear, smoothstep and ease-out-back. Predict where each curve puts the horn at a quarter of the time, then make the move slower. Chapter 2 ### Push and pull - Solenoids and the flyback diode A 12 V push-pull solenoid on a logic-level MOSFET. Predict the coil current from Ohm’s law, watch the diode carry the kick when the MOSFET lets go, and tap faster. - Linear actuators and end stops A 12 V linear actuator on an L298N. Drive it to its end switches, place it by the clock alone, and see dead reckoning come up short the moment the load changes. Chapter 3 ### Feel it - Vibration motors: haptics A coin vibration motor on a 2N2222. Predict its current, find the duty where it will not start, kick-start it, and play and tune haptic patterns. Chapter 4 ### Boss build - Boss: an animatronic face Eyes, eyelids, brows and a jaw on four servos through a PCA9685. Moods from a table, blinks and glances on millis(), a talk command, and a face you make your own. Keep going ## The next course on your track Servos, solenoids and actuators is part of the robotics track, a ladder of courses from zero to expert. Next course ### Sensors and measurement Intermediate: thermistors and RTDs, strain gauges in a Wheatstone bridge, light and IR, current on a shunt and an INA219, ADC resolution and noise, and calibration, finished with a power instrument you check against Ohm's law. Open the next course Track ### Robotics track Motors, servos, sensors and PID control loops, then a rover, a claw machine and a balance bot, every lesson checked on a simulated board. See every course on the track Kits ## Build it on your bench too Every lesson runs in the simulator with nothing to buy. When you want the real thing, these kits have the parts. Have a kit already? ### Find your kit Pick the starter kit you own and run every lesson in its manual with the same parts on the same pins. See every kit Questions ## About Servos, solenoids and actuators Is Servos, solenoids and actuators free? Yes. All 7 lessons of Servos, solenoids and actuators are free and run in your browser, with nothing to install and no parts to buy before you start. Do I need a real Arduino Uno R3? No. Every lesson runs on a simulated Arduino Uno R3 with its parts on the canvas, and the simulator checks each step as you go. When you want to build it for real, the same wiring and code work on a real board. How long does Servos, solenoids and actuators take? About 6 hours: 7 lessons in 4 chapters, each one a few short steps. Your progress is kept, so you can stop after any lesson and pick up where you left off. What will I build? Each chapter ends in a project that puts it together: Easing: motion that looks alive and Linear actuators and end stops. Where do I start? With "Servo pulses: measure, predict, calibrate", and each lesson builds on the one before it. New to circuits? Electronics basics is the course that starts from zero.