Comparison table
| Unit | Price | Torque | Speed | Weight | Voltage | Status |
|---|---|---|---|---|---|---|
| "TT" yellow plastic gear motor (1:48) | $1 – $3 per motor | 0.078 N·m | about 250 rpm no load at 6 V | 30.6 g | 3–6 V | Available |
| N20 micro metal gear motor (GA12-N20, generic) | $2 – $9 per motor | about 0.04 N·m at 6 V (varies) | 30–3,000 rpm by ratio | about 10 g | 3 V | Available |
| Pololu Micro Metal Gearmotor HPCB | $27.45 | 0.20 N·m at 6 V (150:1) | 220 rpm at 6 V (150:1) | – | 6 V or 12 V versions | Available |
| Pololu 37D Metal Gearmotor with 64 CPR encoder | $60.95 | 2.06 N·m at 12 V (50:1) | 200 rpm at 12 V (50:1) | – | 12 V or 24 V versions | Available |
| JGB37-520 encoder gear motor ("520 motor") | $8 – $22 | 0.81 N·m stall at 12 V (1:56) | 205 rpm at 12 V (1:56) | – | 12 V rated. Aslong's datasheet… | Available |
| goBILDA 5203 Series Yellow Jacket Planetary Gear Motor | $54.99 | 2.38 N·m | 312 rpm no load at 12 V | 437 g | 12 V nominal | Available |
| LEGO Technic Large and Medium Angular Motors (SPIKE Prime / Powered Up) | $27.99 – $39.99 | 0.08 N·m rated (Large) | about 213 rpm (Large) | 49–71 g | 7.2 V nominal | Discontinued |
| 28BYJ-48 geared stepper with ULN2003 driver | $3 – $5 per motor and driver | 0.029 N·m at 5 V | about 9–15 rpm | 37 g | 5 V | Available |
| NEMA 17 stepper motor (e.g. StepperOnline 17HS19-2004S1, generic 17HS4401) | $8 – $15 per motor | 0.4–0.59 N·m holding | depends on driver | 390 g | 12–24 V driver supply | Available |
| NEMA 23 stepper motor (e.g. StepperOnline 23HS45-4204S) | $28.70 | holding 3.0 N·m | depends on driver | 1.6 kg | 24–48 V driver supply | Available |
| MKS SERVO42D closed-loop stepper driver (NEMA 17) | $22.99 – $33.99 | set by the NEMA 17 motor | 3000 rpm+ maximum | – | 12–24 V | Available |
| Hoverboard hub motor (6.5 in, 36 V, brushless) | $20 – $60 per wheel | – | about 500–600 rpm at 36 V | – | 36 V nominal | Available |
"TT" yellow plastic gear motor (1:48)
Adafruit #3777 lists $2.95 each (October 2026 check). Amazon multi-packs checked October 2026 run $6.99–$9.99 for 4–8 motors (some with wheels). Typical range across sellers.
The yellow "TT" gearbox motor is the default drive motor of beginner Arduino and micro:bit cars. It is a small brushed can motor in a plastic two-shaft gearbox, sold in huge volumes by unnamed factories, so specs vary between batches. Wheels with a matching double-flat bore are sold everywhere, which is a large part of its popularity.
- Torque
- 0.078 N·m (0.8 kg·cm) at 6 V, 0.039 N·m (0.4 kg·cm) at 3 V (Adafruit)
- Speed
- about 250 rpm no load at 6 V, 185 rpm at 4.5 V, 120 rpm at 3 V (Adafruit #3777). Many sellers list 200 rpm at 6 V, Yahboom lists 245 rpm
- Weight
- 30.6 g (Adafruit)
- Size
- 70 × 22 × 18 mm (Adafruit)
- Voltage
- 3–6 V
- Current
- no load 150 mA ±10 %, stall 1.1 A at 3 V to 1.5 A at 6 V (Adafruit)
- Gearing
- 1:48, plastic spur gears (1:120 and other ratios also sold)
- Motor
- brushed DC (130-size can)
- Feedback
- none (some versions add a slotted disc or Hall encoder)
- Interface
- two wires, needs an H-bridge driver such as TB6612 or DRV8833
- Other
- single- or dual-shaft versions. The dual shaft carries a wheel on one side and an encoder disc on the other. Adafruit's version comes with 200 mm 28 AWG leads
Cheap wheeled robots and classroom car kits where a few dollars per motor matters and precise speed control does not.
Heavy robots, arms or anything needing repeatable odometry, since the plastic gears wear and there is no encoder on most versions.
Robots in the guide that use it
mBot$69.99 – $149.99
ELEGOO Smart Robot Car Kit V4.0$79.99
SunFounder GalaxyRVR Mars Rover Kit$129.99
Yahboom Raspbot V2$114.99 – $144.99 (no Pi)
ACEBOTT ESP32 Mecanum Camera Car$69.99
WeeeBot miniQuote only
Freenove 4WD Smart Car Kit for Raspberry Pi$69.99 (no Pi)The standard motor of countless Arduino 2WD/4WD car kits and the original NVIDIA JetBot-style chassis kits (unconfirmed).
Sources Adafruit #3777 TT motor (specs) ↗ · Yahboom motor introduction (TT and 520 motor specs) ↗ · Amazon TT motor search ↗
Buying Adafruit ships from New York. Amazon multi-packs usually ship with Prime in 1–2 days. AliExpress 1–3 weeks.
N20 micro metal gear motor (GA12-N20, generic)
Google Shopping/RobotShop/AliExpress checked October 2026. AliExpress about $3.50, Handsontec $3.40, Canada Robotix with encoder CA$16.99 (about US$12), RobotShop Aslong 6 V 300 rpm $6.95 ($8.85 with encoder, unconfirmed since RobotShop blocks automated checks), ABRA $9.88. Typical range across sellers.
The N20 (also sold as GA12-N20) copies the 10 × 12 mm form factor that Pololu popularized with its Micro Metal Gearmotors, so brackets and wheels are interchangeable. Generic versions cost a fraction of the Pololu parts but quality and published specs vary between sellers. Versions with a small magnetic encoder are popular for PID-controlled school cars.
- Torque
- varies widely by ratio and seller. One documented example is 0.040 N·m (0.41 kg·cm) stall at 6 V for a 300 rpm version (Canada Robotix). Handsontec's claim of 16 kg·cm stall for its 300 rpm version is not credible
- Speed
- ratios from about 30 to 3000 rpm no load (sold as 3, 6 and 12 V versions). 300 rpm at 6 V is the most common pick for small cars
- Weight
- about 10 g (Handsontec)
- Size
- gearbox 12 × 10 mm cross section, about 34 mm long including the motor (Handsontec), 3 mm D shaft
- Voltage
- 3 V, 6 V or 12 V versions
- Current
- no load about 50–70 mA, stall about 0.4–1 A at 6 V depending on seller data (Canada Robotix 419 mA, Handsontec 1 A)
- Gearing
- metal spur gearbox, many ratios. Sellers quote different ratios for the same rated speed (Handsontec lists 1:97 for its 300 rpm version)
- Motor
- brushed DC (N20 can)
- Feedback
- optional magnetic Hall encoder on the rear shaft. Canada Robotix's 300 rpm version gives about 358 pulses per output revolution across both channels, which is roughly 7 pulses per motor turn (unconfirmed)
- Interface
- two wires (six with encoder), needs an H-bridge driver
Small cars, line followers and compact mechanisms where a 12 mm motor with real metal gears is needed for a few dollars.
Loads above a few hundred grams per motor or anything needing trustworthy datasheets, since generic specs are inconsistent.
Robots in the guide that use it
DFRobot Maqueen Plus V3$69.90
ELECFREAKS Cutebot / Cutebot Pro$29.90 – $49.90
AlphaBot2$97.99 – $146.99Common in micro:bit cars, mini-sumo robots, line followers and small robot grippers.
Sources Canada Robotix N20 with encoder (specs) ↗ · Handsontec GA12-N20 6V 300 rpm ↗ · RobotShop Aslong N20 6V 300 rpm ↗
Buying RobotShop (US warehouse, unconfirmed) and Amazon ship within the US in a few days. AliExpress 1–3 weeks.
Pololu Micro Metal Gearmotor HPCB
Pololu store, October 2026 check, item #3076. The 50:1 HP 6V with 12 CPR encoder (#5160) is $29.95. Prices vary with ratio and encoder option.
Pololu's Micro Metal Gearmotors set the 10 × 12 mm form factor that generic N20 motors copy. The HPCB versions use carbon brushes for a much longer life at high current than the precious-metal-brush HP, MP and LP versions, which Pololu says have lower friction and suit lower-current use. Pololu publishes full performance data for every ratio, which generic N20 sellers rarely do. The 3pi+ Hyper edition uses the 15:1 HPCB 6V, while the Zumo 32U4 (50:1, 75:1 or 100:1 HP) and the other 3pi+ editions (30:1 MP, 75:1 LP) use sister versions of the same family.
- Torque
- 0.20 N·m (2.0 kg·cm) stall at 6 V for 150:1 HPCB 6V. Range across the line 0.09 kg·cm (5:1) to 10 kg·cm (1000:1 HPCB 12V), with Pololu warning that the 380:1 and 1000:1 gearboxes can damage themselves above 25 kg·mm
- Speed
- 220 rpm no load at 6 V for 150:1. Line covers ratios 5:1 to 1000:1, about 35 to 6800 rpm no load
- Size
- 10 × 12 mm gearbox cross section, 3 mm D shaft 9 mm long
- Voltage
- 6 V or 12 V versions
- Current
- 150:1 HPCB 6V, no load 150 mA, stall 1.5 A
- Gearing
- 5:1 to 1000:1 metal spur gearbox (150:1 is 150.58:1, 50:1 is 51.45:1)
- Motor
- brushed DC with long-life carbon brushes (HPCB). Sister lines HP, MP and LP use precious-metal brushes
- Feedback
- optional 12 CPR magnetic quadrature encoder on the extended 1 mm rear motor shaft (about 617 counts per output turn on the 50:1)
- Interface
- two motor wires, needs an H-bridge driver
- Other
- max power 1.1 W for 150:1 HPCB 6V
Small competition robots that need consistent, documented performance and a matching encoder in a 10 × 12 mm package.
Budget builds where generic N20 motors cost a tenth as much, or loads that would stall the gearbox for long.
Robots in the guide that use it
Used across mini-sumo, micromouse and line-follower robots built from Pololu parts.
Sources Pololu Micro Metal Gearmotors (line overview) ↗ · Pololu #3076 150:1 HPCB 6V ↗ · Pololu #5160 50:1 HP 6V with encoder ↗
Buying Pololu ships from Las Vegas, Nevada (same-day shipping on in-stock orders), typically within a few days in the US.
Pololu 37D Metal Gearmotor with 64 CPR encoder
Pololu store, October 2026 check, item #4753. Other ratios and 24 V versions are priced similarly. The same motor without encoder is #4743.
Pololu's largest brushed gearmotor family, sold in 12 V and 24 V versions with nine ratios and an optional built-in encoder. The current version adds a helical first gear stage for lower noise and better efficiency. It is a well-documented alternative to the generic 37 mm "520" encoder motors.
- Torque
- 2.06 N·m (21 kg·cm) stall at 12 V (extrapolated) for 50:1. Pololu recommends keeping continuous loads under 10 kg·cm and momentary loads under 25 kg·cm. Line covers 0.5–49 kg·cm stall
- Speed
- 200 rpm no load at 12 V for 50:1. Line covers 67–10,000 rpm
- Size
- 37 mm diameter, 70 mm long (50:1), 6 mm D shaft 16 mm long
- Voltage
- 12 V or 24 V versions (the 24 V motor draws about half the current)
- Current
- 50:1 12 V, no load 200 mA, stall 5.5 A
- Gearing
- 6.3:1 to 150:1 metal gearbox (nine ratios plus a 1:1 version), helical first stage
- Motor
- brushed DC
- Feedback
- two-channel Hall quadrature encoder, 64 CPR at motor shaft, 3200 CPR at output for 50:1, encoder supply 3.5–20 V
- Interface
- six color-coded leads with a 1×6 female header (motor + encoder)
- Other
- max power 10 W (50:1, 12 V)
Medium wheeled robots (a few kg) that need reliable encoders and documented specs.
Tiny robots or projects on a tight budget, where Chinese JGB37-520 motors cost about a sixth as much.
A common drive motor for medium hobby rovers, balancing robots and university robotics labs.
Sources Pololu 37D Metal Gearmotors (line overview) ↗ · Pololu #4753 50:1 12V with encoder ↗
Buying Pololu ships from Las Vegas, Nevada (same-day shipping on in-stock orders), typically within a few days in the US.
JGB37-520 encoder gear motor ("520 motor")
Yahboom MD520 $7.90 (motor only) on Yahboom's store, October 2026 check. RobotShop $9.90–$11.90 and Oz Robotics JGB37-520B $22 (both unconfirmed, RobotShop blocks automated checks).
The "520" encoder motor pairs a 520-size brushed motor with a 37 mm metal spur gearbox and a small Hall encoder. It is the default drive motor of Chinese ROS education rovers from Yahboom and Hiwonder. Specs differ between factories, so Yahboom's published figures are used here. Yahboom also sells an L-shaped 1:40 version rated 4.4 kg·cm at 150 rpm.
- Torque
- Yahboom MD520 1:56 at 12 V, rated 0.64 N·m (6.5 kg·cm), stall 0.81 N·m (8.3 kg·cm). 1:30, rated 3.3 kg·cm, stall 4.8 kg·cm. 1:19, rated 2.2 kg·cm, stall 3.1 kg·cm
- Speed
- 205 rpm (1:56), 333 rpm (1:30), 550 rpm (1:19) at 12 V (Yahboom). Aslong's JGB37-520 datasheet lists ratios from 6.3:1 to 810:1, roughly 10 to 1600 rpm no load at 12 V
- Voltage
- 12 V rated. Aslong's datasheet also lists 24 V versions, and some sellers offer 6 V (unconfirmed)
- Current
- rated 0.3 A, stall 3 A (1:19, 1:30) to 4 A (1:56) at 12 V (Yahboom)
- Gearing
- 37 mm metal spur gearbox, 1:19, 1:30, 1:56 and many others
- Motor
- brushed DC (520 can) with carbon brushes
- Feedback
- AB-phase incremental Hall encoder, 11 pulses per motor revolution (Yahboom)
- Interface
- 6-pin PH2.0 cable (motor + encoder) on Yahboom versions
- Other
- 6 mm D output shaft (eccentric on Yahboom's drawing)
ROS rovers of 2–8 kg that need wheel odometry at low cost.
Quiet indoor robots or precise motion, since gearbox backlash and noise are high and datasheets vary between factories.
Robots in the guide that use it
ROSMASTER M1$349.90 – $1,169.90
ROSMASTER A1$339.90 – $1,179.90
ROSMASTER M3$779.90 – $2,409.90
ROSMASTER R2$655 – $2,375
ROSOrin$299.99 – $1,499.99
ROSOrin Pro$769.99 – $2,349.99
Hiwonder JetTank$659.99 – $1,239.99
Hiwonder JetAcker$399.99 – $2,389.99
Hiwonder JetAuto$439.99 – $2,429.99
Hiwonder LanderPi$429.99 – $1,039.99Used in many Chinese ROS education cars and balancing robots.
Sources Yahboom 520 motor specs (tutorial page) ↗ · Yahboom store MD520 ↗ · Aslong JGB37-520 datasheet (scanned PDF) ↗
Buying Yahboom ships from Shenzhen, China, with free standard shipping on orders over $50 and most orders arriving within 6 working days of dispatch. Amazon and AliExpress also sell generic versions, and RobotShop lists the Yahboom version (unconfirmed).
goBILDA 5203 Series Yellow Jacket Planetary Gear Motor
goBILDA store, October 2026 check. Other ratios in the series are priced similarly (unconfirmed). FTC teams get a 25 % discount on most of the store.
The Yellow Jacket is goBILDA's planetary gearmotor line, built around an RS-555 brushed motor with steel planetary gears and a built-in encoder. It is a staple of FIRST Tech Challenge robots, and goBILDA's site carries FTC legality notes, an FTC starter kit and an FTC team discount. Its 8 mm REX shaft fits goBILDA's hubs and channel system.
- Torque
- 2.38 N·m (24.3 kg·cm) stall at 12 V (19.2:1)
- Speed
- 312 rpm no load at 12 V (19.2:1)
- Weight
- 437 g
- Voltage
- 12 V nominal, encoder 3.3–5 V
- Current
- no load 0.25 A, stall 9.2 A at 12 V
- Gearing
- 19.2:1 planetary, steel gears (other ratios sold in the series)
- Motor
- brushed DC, RS-555 size
- Feedback
- relative quadrature magnetic Hall encoder, 537.7 pulses per output revolution (19.2:1)
- Interface
- 3.5 mm bullet connectors for power, 4-pin JST XH for encoder, 470 mm leads
- Other
- 8 mm REX output shaft 24 mm long, 18 AWG leads
Competition and mid-size robots that need a tough planetary gearmotor with an encoder and a modular mounting system.
Small or battery-light robots, since it weighs 437 g and stalls at over 9 A.
Very widely used in FIRST Tech Challenge (FTC) competition robots.
Sources goBILDA 5203 19.2:1 product page ↗ · goBILDA shipping information ↗
Buying goBILDA ships within the US by USPS Ground Advantage (5–10 business days), flat rate (3–5 days) or FedEx, after 1–2 business days of handling. Its warehouse is in Winfield, Kansas (unconfirmed, the site does not state a city).
LEGO Technic Large and Medium Angular Motors (SPIKE Prime / Powered Up)
LEGO.com, October 2026 check. Powered Up 88017 Large Angular Motor $27.99 (reduced from $34.99) and 88018 Medium Angular Motor $39.99, both marked "Retired Product" but still showing an Add to Bag button. LEGO Education versions 45602/45603 are listed as retired.
These motors came with LEGO Education SPIKE Prime and were reused by Mindstorms Robot Inventor. Each one has an absolute angle sensor, so a robot knows the shaft position at power-up. LEGO Education has retired the SPIKE versions, and LEGO.com now marks the Powered Up 88017/88018 motors (released 2021) as retired too, although they could still be ordered in October 2026. The Powered Up motors use the same design and connector as the Education ones.
- Torque
- Large, rated 0.08 N·m (8 N·cm) at 135 rpm and 7.2 V (LEGO spec sheet, matched by Philohome's 7.2 V measurement), stall about 0.335 N·m (33.5 N·cm) at 9 V (measured). Medium, rated 0.035 N·m (3.5 N·cm) at 135 rpm and 7.2 V (LEGO spec sheet, unconfirmed), stall about 0.135 N·m (13.5 N·cm) at 9 V (measured)
- Speed
- no load about 213 rpm (Large) and 228 rpm (Medium) at 9 V (measured)
- Weight
- Large 71 g, Medium 49 g (measured)
- Voltage
- 7.2 V nominal (SPIKE hub battery)
- Current
- no load 110 mA (Large), 100 mA (Medium). Stall about 1.8 A (Large), 0.85 A (Medium) at 9 V (measured)
- Motor
- brushed DC with internal gearbox
- Feedback
- built-in relative rotation sensor with 1° resolution plus absolute position, with a zero mark on the hub
- Interface
- LPF2 / Powered Up 6-pin connector to a LEGO hub
- Other
- measured figures from Philippe Hurbain's LEGO motor comparison, which he says match LEGO's official spec sheets. Mechanical power is under 1 W (Medium) and almost 2 W (Large)
LEGO-based robots, FIRST LEGO League and classroom builds that need position-controlled motors with no extra electronics.
Non-LEGO robots or anything needing more than about 2 W of mechanical power per motor.
Robots in the guide that use it
Also used with the LEGO Technic Large Hub and Pybricks-based custom builds.
Sources LEGO Education 45602 Large Angular Motor (retired) ↗ · LEGO Education 45603 Medium Angular Motor (retired) ↗ · LEGO.com 88017 Large Angular Motor ↗ · Philohome LEGO motor measurements ↗
Buying LEGO.com ships within the US while retired stock lasts. BrickLink sellers carry used and sealed units.
28BYJ-48 geared stepper with ULN2003 driver
Amazon 5-packs with ULN2003 boards checked October 2026 cost $13.99–$16.99 (ELEGOO $14.99, HiLetgo $14.59). Adafruit sells its 1/16-geared bare motor (#858) for $4.95. Typical range across sellers.
The cheapest stepper motor on the market, almost always sold bundled with a ULN2003 driver board. Its internal gearbox (1/64 on the common version, 1/16 on some) gives fine resolution but very low speed. Many hobbyists convert it to bipolar for more torque.
- Torque
- pull-in torque 0.029 N·m (300 gf·cm) at 5 V (datasheet). Adafruit quotes 150 gf·cm holding torque for its 1/16 version
- Speed
- rated stepping frequency 100 Hz, maximum pull-in frequency above 600 Hz (datasheet), which is roughly 9 rpm in half-step mode on the 1/64 version. Hobbyists often run it at 10–15 rpm (unconfirmed)
- Weight
- 37 g (Adafruit)
- Size
- 28 mm diameter, 19 mm body (datasheet), 5 mm flatted shaft about 10 mm long
- Voltage
- 5 V (12 V version also sold)
- Current
- coil resistance 50 Ω ±7 % (datasheet), so roughly 100 mA per coil at 5 V
- Gearing
- 1/64 nominal internal plastic gear train (datasheet). Adafruit's #858 is a 1/16.128 variant with 516 steps per turn, so the ratio depends on which version a seller supplies
- Motor
- 4-phase unipolar permanent-magnet stepper
- Feedback
- none (open loop)
- Interface
- 5-wire unipolar, driven by a ULN2003 Darlington board from four GPIO pins
- Range
- continuous, 2048 full steps or 4096 half steps per output revolution on the 1/64 version (stride angle 5.625°/64)
Learning stepper control and slow positioning tasks like dials, blinds and turntables.
Driving wheels or arm joints, since it is slow, weak and its plastic gears have noticeable backlash.
Common in Arduino starter kits, small clocks, camera sliders and simple plotters.
Sources 28BYJ-48 datasheet (Mouser PDF) ↗ · 28BYJ-48 datasheet (Components101 PDF copy) ↗ · Adafruit #858 ↗ · Amazon 28BYJ-48 + ULN2003 packs ↗
Buying Amazon packs ship with Prime in 1–2 days. Adafruit ships from New York. AliExpress 1–3 weeks.
NEMA 17 stepper motor (e.g. StepperOnline 17HS19-2004S1, generic 17HS4401)
StepperOnline 17HS19-2004S1 $9.62 (single, $8.03 at 100+) on omc-stepperonline.com; Amazon 17HS4401 singles about $12, 5-packs $32.99, October 2026 check. Typical range across sellers.
NEMA 17 is a 42 mm frame standard, not one product, and the 17HS-series parts from StepperOnline are among the most common. The 3D printer boom made them cheap, which is why most open-source desktop arms use them with gearboxes. The AR4 build manual specifies StepperOnline 17HS15-1684D NEMA 17 motors with 10:1 and 50:1 planetary gearheads on J1 and J3 and a NEMA 23 on J2, PAROL6 uses NEMA 17 motors with 10:1 or 20:1 reductions, Thor uses NEMA 17 motors with 5:1 planetary gearboxes on its lower joints, and the Moveo BOM lists NEMA 17, NEMA 23 and NEMA 14 motors.
- Torque
- holding 0.59 N·m (17HS19-2004S1, 48 mm body) or about 0.4 N·m (17HS4401, 38–40 mm body, unconfirmed)
- Speed
- depends on driver and supply voltage. Torque drops off at higher speeds
- Weight
- 390 g (17HS19-2004S1)
- Size
- 42 × 42 mm frame, 48 mm body (17HS19-2004S1), 5 mm D shaft 24 mm long
- Voltage
- driven by a current-limiting chopper driver at 12–24 V typical
- Current
- 2.0 A per phase (17HS19-2004S1), about 1.5–1.7 A (17HS4401, unconfirmed)
- Motor
- 2-phase hybrid stepper
- Feedback
- none (open loop). Closed-loop versions add an encoder
- Interface
- 4-wire bipolar to a step/dir driver such as A4988, TMC2209 or DM542. The 17HS19-2004S1 comes with a 1 m cable and 4-pin Harwin connector
- Range
- continuous, 200 full steps per revolution (1.8°)
- Other
- 17HS19-2004S1, 1.6 Ω and 3.0 mH per phase
Open-loop positioning in DIY arms, printers and camera rigs, usually with a belt or planetary reduction.
Fast or backdrivable joints, battery robots that idle a lot (it draws current while holding), or anything that must detect missed steps without an encoder.
Robots in the guide that use it
Annin Robotics AR4$1,189 kit + motors/drivers
PAROL6~$2,500 kit / ~$3,800…
ThorDIY, < €350 parts
BCN3D MoveoDIY (parts only)Also the standard motor in 3D printers and CNC routers, and in many other DIY arms.
Sources StepperOnline 17HS19-2004S1 ↗ · Annin Robotics AR4 build manual V1.6 (motor list, PDF) ↗ · Hackaday on PAROL6 (NEMA 17 + 10:1/20:1) ↗ · BCN3D Moveo BOM (PDF) ↗ · Amazon 17HS4401 search ↗
Buying StepperOnline ships from US, German, UK, Australian, Japanese, Russian and Chinese warehouses, dispatching within 24 hours (except Sunday) when in stock. US warehouse deliveries are quoted at 4–7 working days. Amazon Prime packs ship in 1–2 days.
NEMA 23 stepper motor (e.g. StepperOnline 23HS45-4204S)
omc-stepperonline.com, October 2026 check, single unit ($23.97 at 100+).
NEMA 23 is the 57 mm frame step up from NEMA 17, used where a desktop arm needs much more holding torque. The 23HS45-4204S is among StepperOnline's strongest 57 mm motors. The AR4 uses a shorter NEMA 23 (23HS22-2804D) with a 50:1 planetary gearbox on its J2 shoulder joint, and the Moveo BOM lists two 112 mm NEMA 23 motors.
- Torque
- holding 3.0 N·m (23HS45-4204S)
- Weight
- 1.6 kg (23HS45-4204S)
- Size
- 57 × 57 mm frame, 113 mm body, 10 mm shaft (23HS45-4204S)
- Current
- 4.2 A per phase
- Gearing
- none (gearbox versions sold)
- Motor
- 2-phase hybrid stepper, insulation class B
- Feedback
- none (open loop)
- Interface
- 4-wire bipolar to a step/dir driver such as DM556 or DM542, 400 mm leads
- Range
- 200 full steps per revolution (1.8°)
- Other
- 0.88 Ω, 3.4 mH per phase
Shoulder and base joints of larger DIY arms and CNC axes that need several N·m.
Light or mobile robots, since a single motor weighs over 1.5 kg and needs a large driver.
Robots in the guide that use it
Common in CNC routers and larger DIY arms such as Arctos.
Sources StepperOnline 23HS45-4204S ↗ · Annin Robotics AR4 build manual V1.6 (motor list, PDF) ↗ · BCN3D Moveo BOM (PDF) ↗
Buying StepperOnline ships from US, German, UK, Australian, Japanese, Russian and Chinese warehouses, dispatching within 24 hours (except Sunday) when in stock. US warehouse deliveries are quoted at 4–7 working days.
MKS SERVO42D closed-loop stepper driver (NEMA 17)
MakerBase3D official store, October 2026 check (variants, driver board with or without motor, unconfirmed). Resellers list it from about $11 to $58.
The SERVO42D is a driver board that bolts to the back of a NEMA 17 motor, reads the shaft with a magnetic encoder and runs field-oriented control. That turns a cheap open-loop stepper into a closed-loop actuator with bus control. Makerbase released the first manual version in March 2023 and has updated firmware regularly since, reaching V1.0.9 in November 2025.
- Speed
- 3000 rpm+ maximum (manual), 1500 rpm in closed-loop pulse mode
- Voltage
- 12–24 V (manual)
- Current
- 0–3000 mA in 200 mA steps, default 1600 mA for the 42D (manual)
- Motor
- mounts on the back of a standard NEMA 17 hybrid stepper
- Feedback
- 16384-line (14-bit) magnetic encoder, position, speed and torque loops with FOC (manual)
- Interface
- step/dir pulse input (up to 160 kHz) plus RS485, Modbus RTU or CAN depending on version
- Other
- stall detection and limit/homing inputs. 20 kHz loop update rate (reseller data, unconfirmed)
Upgrading NEMA 17 arms and gantries so missed steps are caught and corrected, and daisy-chaining joints over CAN.
Builds that need a true servo's torque-to-weight or backdrivability, since it is still a stepper underneath.
Used in DIY arms such as Arctos and in printer and CNC upgrades (unconfirmed).
Sources Makerbase MKS-SERVO42D/57D manuals (GitHub) ↗ · MKS SERVO42D/57D CAN user manual V1.0.9 (PDF) ↗ · MakerBase3D store ↗
Buying MakerBase3D ships from Guangzhou, China (Liwan District address on its site). Also sold on AliExpress (1–3 weeks) and Amazon.
Hoverboard hub motor (6.5 in, 36 V, brushless)
Google Shopping, October 2026 check. AliExpress $19.84–$40.86, eBay $34.99 single, Amazon listings similar. Used hoverboards are a cheaper source.
Hoverboard wheels are brushless, gearless hub motors with Hall sensors and a solid tire, built in huge numbers, so a pair costs less than most robot gearmotors of similar torque. They are the one brushless entry in this category and need a three-phase controller rather than an H-bridge. Open-source firmware for the stock hoverboard controller (EFeru's FOC firmware, started October 2019) and ODrive's hoverboard guide made them a standard part for DIY rovers.
- Speed
- KV around 16 rpm/V (ODrive docs), so roughly 500–600 rpm unloaded at 36 V (calculated, unconfirmed)
- Size
- 6.5 in (165 mm) wheel with solid tire
- Voltage
- 36 V nominal
- Motor
- outrunner brushless DC hub motor, 30 magnet poles (15 pole pairs). Not a brushed gearmotor
- Feedback
- three built-in Hall sensors, 90 counts per revolution (15 pole pairs × 6 Hall states, ODrive docs)
- Interface
- three phase wires plus Hall cable, needs a BLDC controller (stock hoverboard board with FOC firmware, ODrive, VESC)
- Other
- 350 W rating per seller listings (unconfirmed). Phase resistance about 0.18 Ω, inductance about 0.34 mH (ODrive calibration example)
Cheap direct-drive wheels for heavy DIY rovers and carts that need real torque and quiet operation.
Small robots or precise low-speed odometry, since 90 Hall counts per turn is coarse.
Used in many DIY rovers, telepresence robots and carts built on the hoverboard-firmware-hack-FOC firmware.
Sources ODrive hoverboard motor guide ↗ · hoverboard-firmware-hack-FOC (GitHub) ↗
Buying Amazon and eBay ship in the US in a few days. AliExpress 1–3 weeks. Used hoverboards from local sellers.