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 simulatorAll 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.
0 of 7 done
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.
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 simulatorThe 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.
- Open236 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
- Locked200 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
- ProjectLocked436 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.
- Locked218 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
- ProjectLocked436 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.
- Locked236 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.
- Locked249 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.
Servos for real
- Servo pulses: measure, predict, calibrateSend 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 partAn 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 aliveThe 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.
Push and pull
- Solenoids and the flyback diodeA 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 stopsA 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.
Feel it
- Vibration motors: hapticsA 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.
Boss build
- Boss: an animatronic faceEyes, 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.
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 courseRobotics 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 trackKits
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.
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 kitQuestions
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.