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Project Notes

#601 Low Power Mini Servos

Testing a few low power mini servo motors with an Arduino and MOSFET level shifter.


Here’s a quick demo..



So-called low power / mini servos are generally designed to work from lithium battery packs in RC vehicles - so voltages in the 3.7 to 4.2V range. I have a few of these servos, and the notes that follow document some quick tests using an Arduino Uno as a driver.

2.2g Mini Digital Servo

Available from, aliexpress and other sources.

Item Specification
No-Load Velocity 3.7V: 0.07 ± 0.01 sec/60˚ , 4.2V: 0.06 ± 0.01 sec/60˚
No-load current 3.7V: 60 ± 15mA , 4.2V: 65 ± 15mA
Stop Torsion 3.7V: , 4.2V:
Stop Current 3.7V: 210 ± 30mA , 4.2V: 310 ± 30mA
Standby Current 3.7V: 2 ± 1mA , 4.2V: 2 ± 1mA
No-load life 3.7V: >6000 times , 4.2V: >4000 times
Limit angle of mechanism 180˚ ± 10˚
Weight 2.2 ± 0.2g
Wire Length 110 ± 5 mm
Size 20mm x 16mm x 8mm / 0.78in x0.62in x 0.31in


In practice, the servos I got worked smoothly from ~3.5V

1.7G Mini Digital Servo

Available from, aliexpress and other sources.

Item Specification
Brand T-power
Operating voltage 2.8V-4.2V (No more than 4.2 V, or be damaged)
Operating speed 0.06s/60°2.8V, 0.05s/60°3.7V
Torque value 0.06Kg/2.5V, 0.075Kg/3.7V
Gear type plastic
Connector mini JST
line length 10cm
Size 20206mm
Weight 1.7g


In practice, the servo I got seemed to need at least 4V to rotate smoothly.


Since the Arduino runs at 5V, the PWM control signal is put through a MOSFET level shifter to prevent damage to the servo. NB: I suspect the servo control pin is probably 5V tolerant, but I’ve not put that theory to the test!

The servos are also separately powered from a bench power supply - I varied the voltage to test the impact on performance.



Credits and References

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This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.