Web Client

The Kinisi web client is a browser app for driving a Kinisi Motor Controller straight from your computer — no install, no SDK, no code. It is useful for bringing a new board up, checking wiring and motor direction, tuning PID gains, and driving a platform around before you write any software against it.

The client talks to the board over USB using the browser's Web Serial API. Everything runs locally in your browser; nothing about your board is sent anywhere.

Source code: vsreality/jskinisi.

Before you start

• A Chromium-based desktop browser — Chrome, Edge, or Opera. Firefox and Safari do not implement Web Serial, and neither do mobile browsers.
• The controller connected to your computer with a USB cable.
• Motors powered from the controller's motor supply, if you intend to spin them.

caution

Motors run as soon as you command a speed. Put the robot on blocks, or make sure the wheels are clear, before setting a speed for the first time.

Connecting

Open kinisiclient.vsreality.com and press Connect.

The browser then shows its own device picker listing the serial ports it can see. Choose the Kinisi controller and confirm. The client never sees any device you do not pick.

Once the link is up:

• The header shows a green Connected indicator, visible from every section.
• The sections in the left sidebar unlock, and the client opens Motor for you.
• Reconnecting later reopens whichever section you were last working in.

To finish, go back to Connection and press Disconnect. Disconnecting is not just a hang-up: the client stops the platform controller, removes all four motor controllers, and stops all four motors first, so the robot does not carry on running with the page closed.

tip

The controller keeps applying the last command it received. If you set a speed and then close the tab without disconnecting, the motors keep turning.

Motor — direct control

The Motor section drives a single motor open-loop and reads its encoder. It is the quickest way to confirm that a motor is wired correctly and that its encoder counts in the right direction.

Motor

• Motor Index — which of the four channels (0-3) the controls act on.
• Is Reverse — flips the motor's direction, so you can fix a swapped pair of motor leads in software instead of rewiring.
• Initialize Motor — configures the channel with that direction.
• Speed (PWM) — duty cycle from -100 to 100. Set motor Speed applies it (initializing the motor first if needed).
• Stop motor — sets the motor's speed to zero.
• Brake motor — engages the brake, bringing the motor to a stop far more sharply than simply commanding zero.

Encoder

• Encoder Index and Encoder Resolution (ticks/rev) — the resolution is ticks per revolution of the wheel, so on a geared motor it is the count at the output shaft rather than at the motor itself. The default, 1425.1, matches the geared motors used on the reference platforms.
• Initialize encoder — applies the resolution and direction.
• Get Encoder Value — reads the raw tick count.
• Start / Reset / Stop / Get Odometry — unlock once the encoder is initialized, and turn the tick count into distance travelled by that wheel.

If the encoder counts down while the wheel drives forward, tick the encoder's own Is Reverse and initialize it again.

Motor Controller — closed-loop speed

The Motor Controller section runs a PID loop over a single motor so it holds a commanded speed in radians per second, instead of a raw PWM duty cycle. This is the section to use when tuning gains.

1. Under Motor & Encoder, pair the motor with the encoder that measures it, set their directions, and enter the encoder resolution.
2. Under PID Parameters, set Kp, Ki, Kd and an Integral Limit. The integral limit caps wind-up so the loop recovers cleanly when a wheel is blocked and then released.
3. Controller Frequency sets how often the loop runs, from 1 to 1000 Hz. It is a global setting shared by every controller on the board.
4. Press Initialize Motor Controller, then move the Speed (radian/sec) slider and press Set motor Speed.

The chart plots the loop live, polled twice a second:

• target_speed — what you asked for.
• current_speed — what the encoder measures.
• error — the difference the loop is working against.
• output — the PWM the loop is applying.

Raise Kp until the measured speed reaches the target quickly, then add Ki to remove any steady offset. If the trace oscillates around the target, back Kp off. Reset Controller clears the accumulated error without tearing the controller down; Stop Controller removes it entirely.

Platform — driving the whole robot

The Platform section treats the wheels as one vehicle, so you command the robot's motion rather than individual motors.

Platform Settings — choose Mecanum, Omni or Differential, mark any reversed motors and encoders, enter the geometry (wheel diameter, and the platform's length and width, radius, or wheel base depending on the type) and the encoder resolution, then press Initialize.

Open-loop driving — the X, Y and T sliders command forward, sideways and rotational motion as PWM percentages from -100 to 100. The platform uses a REP-103 right-handed frame, so +X is forward, +Y is left, and +T rotates counter-clockwise. Set Platform Velocity applies them. Brake Platform holds the wheels against motion; Coast Platform lets them spin down freely. Both also stop the velocity controller if one is running.

Keyboard driving — tick Enable keyboard driving to steer with the keyboard: W/S forward and back, A/D rotate, and Shift + A/D to strafe sideways on a platform that supports it. It drives open-loop in PWM until you start a platform controller, and in real velocity units afterwards.

Controller Settings — the same PID parameters as above, applied to the platform as a whole. Once Initialize Platform Controller has run, the target boxes take real units: metres per second for X and Y, radians per second for T.

Odometry — set the update frequency and press Start Odometry; Get Odometry then reports the platform's estimated position as X, Y and Theta. Reset Odometry returns that estimate to zero, which is handy at the start of a run.

GPIO

The GPIO section exercises the board's eight general-purpose pins and the status LED — a quick way to test limit switches, endstops and indicators.

Each pin has four modes: INPUT_PULLDOWN, INPUT_PULLUP, INPUT_NOPULL and OUTPUT. Picking a mode configures the pin on the board immediately.

• Input pins show a Read button and the value last read.
• Output pins show a slider that switches the pin between 0 and 1.

ToggleStatusLED flips the controller's on-board LED, which is a fast way to confirm you are talking to the board you think you are.

Where to next

Every control in the client maps onto a command in the serial protocol, so anything you can do here you can also do from your own software. See the command documentation for the full protocol, or the Python library examples to script the same operations with pykinisi.