The workhorse of the low-cost arm movement. 4096-step magnetic encoder, TTL half-duplex daisy chain, aluminium gears on the 30 kg·cm variant. This is the servo inside SO-100 / SO-101 and most hobby legged bots.

Palm-sized serial servo for fingers and small joints. Same bus as the STS series so it daisy-chains into the same controller, just with a fraction of the torque.

Entry point into the Dynamixel X ecosystem: full position/velocity/current control modes, PID gains exposed over the bus, and the same protocol as the flagship XM/XH units so code ports upward unchanged.

The default joint of academic robot arms. Metal gears, full current sensing, profile-based trajectory control with acceleration ramps, and a documented register map you can drive from any language.

The XM430's bigger sibling for shoulder and hip joints. Same register map, same bus, roughly 2.5x the torque — so a design can scale up without a rewrite.

The part that made cheap humanoids possible. A BLDC with a low-ratio planetary reducer and an integrated FOC driver speaking CAN, priced like a hobby servo and behaving like a robot joint.

The Go1 joint motor sold separately — the single cheapest way to buy a properly engineered legged-robot actuator with real torque density.

A sealed, IP-rated integrated servo with a 1:6 to 1:10 planetary stage. Popular for outdoor and industrial-leaning builds where you want a bolt-on joint with a datasheet.

The cheapest repeatable motion you can buy. 1.8° per full step, 200 steps per revolution, no feedback — it either works or it silently skips and ruins the part.

The step up for routers and heavier gantries. Roughly 7x the holding torque of a NEMA 17 at 8x the current draw.

A NEMA 23 with an encoder and driver glued to the back. Fixes the stepper's one fatal flaw — it knows when it has lost position, and can correct or fault instead of silently ruining the job.

A 100-turn hollow-shaft BLDC built for camera gimbals: high torque per amp, low speed, zero cogging at low current. The standard testbed for learning FOC.

The reference hobby-to-pro FOC drive. Closed-loop torque, velocity and position control on any BLDC, with encoder and absolute-hall support and a real tuning tool.

A servo-driven leadscrew in a tube. Gives you linear motion with a standard RC PWM input, which is enormously convenient for grippers, hatches and camera lifts.

The classic fast standard-size RC servo: titanium-geared, 0.08 s per 60° at 6 V. When you need a fast small joint and don't care about absolute position feedback, this is the answer.

The gold standard for robot joints. A 100:1 reduction in a pancake the size of a hockey puck, with essentially zero backlash and high torsional stiffness.

Bolt-on torque multiplication for a stepper. Cheap ones have 1–3° of backlash, which is fine for a camera axis and fatal for a precision arm.

The lightest and cheapest way to get a 3:1 reduction. Zero backlash when tensioned, and it isolates shock loads — but it stretches and it will not hold a static torque without tension.

Turns rotation into linear motion and, with a 2 mm lead, is self-locking — it holds a vertical load with the motor off. Slow, but it will not drop your payload.

Print a 20:1 to 40:1 reduction for the cost of filament. Used all over the open-source legged-robot scene because it puts real torque behind a cheap BLDC.

A 12-bit absolute magnetic encoder on a 3 mm chip, for the price of a coffee. Stick a diametric magnet on the shaft and you have joint feedback.

The AS5600's serious sibling: 14-bit, SPI, with ABI quadrature output so it can drive both a motor controller and an MCU counter at once.

Capacitive rather than optical, so dust and oil don't kill it. Comes with a set of shaft sleeves covering 2 mm to 8 mm — one part fits almost any motor.

Does the sensor fusion for you. Onboard ARM core outputs a quaternion, gravity vector and linear acceleration — no Kalman filter to write, no magnetometer calibration nightmare.

Low-noise, low-latency 6-axis. No magnetometer, no fusion — you get clean raw rates and write the estimator yourself, which is what legged-robot people actually want.

A 4 m laser rangefinder in a 5 mm package. Uses actual time-of-flight so it is not fooled by black or shiny targets the way IR reflectance sensors are.

The LiDAR almost every hobby SLAM project starts with. 360° scan, 12 m range, spin at 5.5 Hz, and it speaks a simple serial protocol with ROS 2 drivers already written.

The A1's outdoor-capable upgrade: 30 m range and 32k samples per second, so it resolves a person at distance instead of a blob.

The cheapest way into real 3D LiDAR: 360° horizontal, -7° to +52° vertical, 40 m range, in a 265 g puck. Built-in IMU makes LIO pipelines much easier.

The default depth camera for manipulation research. Active IR stereo, 90° × 87° field of view (wide enough for a gripper's working volume), plus an IMU for VIO.

Purpose-built for the last 7 cm to 50 cm — exactly the range where a robot hand actually operates. Higher depth accuracy than the D435i at that distance.

Stereo depth plus a 4 TOPS vision processor that runs your neural network inside the camera. Depth-aligned detections come out of the USB cable already solved.

A polymer pad whose resistance drops as you press it. Crude, hysteretic, but it costs eight dollars and it stops your gripper from crushing an egg.

Measures bus voltage and current across a shunt and reports both over I²C. Ten lines of code buys you the ability to see a joint stalling before it burns.

Centimetre-level positioning outdoors given a correction stream. Multi-band, multi-constellation, and the module behind most affordable outdoor robot localisation.

The default high-level computer for a mid-size robot. Real PCIe, two camera ports, and enough CPU to run ROS 2 nodes, a web dashboard and a modest neural network at once.

67 TOPS in 25 W for under $250. The moment your perception needs a real neural network at frame rate, this replaces the Pi and everything suddenly fits in the time budget.

The step up for humanoids and mobile manipulators running multiple camera streams plus a policy network. 100 TOPS and 16 GB of shared memory.

Dual-core 240 MHz with Wi-Fi and BLE built in. Runs the control loop, drives the servos, and serves a web UI over the air for five dollars.

600 MHz Cortex-M7 with FPU and 1 MB RAM. The board legged-robot hobbyists reach for when the math needs to run at 1 kHz and a 16 MHz AVR is not going to do it.

100 MHz Cortex-M4F with excellent timers and FPU. The board behind most SimpleFOC and custom BLDC driver designs, and the one with the best free toolchain.

The PIO peripheral is the trick: eight programmable state machines that can generate perfectly-timed signals in hardware. Drives 16 servos, reads quadrature encoders, or bit-bangs any protocol without touching the CPU.

The default 18650: 3000 mAh with a 15 A continuous rating. A good balance of capacity and current, and the cell most power-tool and robot packs are built from.

4200 mAh at 45 A continuous. This is the cell that makes 6S quadruped packs work — the current headroom means the pack doesn't sag when twelve motors demand peak torque at once.

The highest power density you can buy off the shelf, at the cost of safety margin. 50C on 5 Ah is a 250 A burst rating — enough to launch anything into a wall.

Balances cells and cuts off on over-current, over-voltage and under-voltage. Non-negotiable on a hand-built pack — the failure mode without one is thermal runaway.

5 V at 5 A from up to 38 V in, with a genuinely honest current rating and good thermal behaviour. The regulator you buy when you are tired of cheap modules browning out your Pi.

350 W of clean 24 V from mains for bench testing. Every robot project eventually needs a power supply that can feed the motors on the bench without a battery in the loop.

The Lego of robot frames. Bolt-together, reconfigurable, and available in every length. Not as stiff per gram as carbon, but you can rebuild the robot in an afternoon.

Four times the second moment of area of 2020 for twice the mass. This is what a gantry that must not deflect uses.

The best stiffness-per-gram available without machining. Roll-wrapped carbon tube is what quadcopter arms and lightweight robot links are made from.

Carbon-fibre-filled nylon printed on a hobby printer gets you near-injection-moulded strength for brackets, joint housings and gearbox shells — if you anneal it and orient the layers correctly.

The industry-standard two-finger adaptive gripper. Fingers conform to the object, 85 mm stroke, and it has been integrated into more research arms than anything else.

The 2F-85's smaller sibling: 50 mm stroke, higher force density, built for cobot wrists where mass at the flange matters.

For flat, non-porous objects nothing beats suction: no grasp planning, no finger geometry, just a cup and a venturi. The standard end effector for cardboard and sheet goods.

Fingers with a ribbed triangular structure that curl around an object when pushed into it. No sensors, no control loop, and it picks up a tomato and a wrench with the same finger.

Holds steel parts with no air and no fingers, and an electro-permanent design keeps holding after power is cut — which is the safety property that matters.