Nintendo Switch 2 Pro Controller → PF400

Jog a Precise Automation PF400 robot with a Nintendo Switch 2 Pro Controller plugged into your computer via USB. Pure Python, no Steam, no extra drivers — just hidapi and pyusb.

The NS2 Pro Controller doesn't speak standard HID out of the box. This package includes a small USB-init routine (adapted from dannydarvish/Switch2ProMac) that flips it into HID mode, plus the jog script that talks to the robot's TCP Command Server (TCS) on port 10100.

What's in the box

File	What it does
ns2_init.py	Sends a magic USB sequence that switches the NS2 Pro into HID streaming mode. Run this every time the controller is plugged in or powered up.
ns2_pf400.py	The main script. Opens the controller via HID and streams movej commands to the robot.
ns2_dpad_probe.py	Helper. If your D-pad fires the wrong joint, run this — it asks you to press each direction and prints the bit each one toggles. Patch decode_buttons in ns2_pf400.py accordingly.
requirements.txt	Two pip packages: hidapi, pyusb.

Setup

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

On macOS, pyusb needs libusb:

brew install libusb

On Linux, you'll likely need a udev rule so the script can claim the USB interface without root. Drop this at /etc/udev/rules.d/99-ns2pro.rules and reload (sudo udevadm control --reload && sudo udevadm trigger):

SUBSYSTEM=="usb", ATTRS{idVendor}=="057e", ATTRS{idProduct}=="2069", MODE="0666"

Usage

1. Plug in the controller via USB-C.
2. Initialize HID mode (every plug-in / power-cycle):

   python3 ns2_init.py

   You should see ~300 reports stream in over 4 seconds — proof it's working.
3. Make sure your robot is reachable and TCS is up on 192.168.0.1:10100 (the default). Robot must be homed and the Virtual MCP in Computer Control mode.
4. Run the jog script:

   python3 ns2_pf400.py

Stop with the B button on the controller.

Controls

Input	Action
D-pad up / down	J1 vertical column (up = raise)
Left stick X	J2 shoulder
Right stick X	J3 elbow
L / R	J4 wrist rotate (digital, hold to jog)
ZL / ZR	J5 gripper close / open
YL / YR (3rd L/R pair / back paddles)	Speed scale − / +
Plus	Reset speed scale to 1.0
A	Print current pose (for teach points)
Y	Toggle motor power (HP) on/off
B	Halt and quit
Minus	Emergency stop (halt + HP off, then quit)

The left stick Y-axis and right stick Y-axis are ignored (J1 lives on the D-pad).

Configuration

Everything you'd reasonably want to tune is in the CONFIG block at the top of ns2_pf400.py:

• ROBOT_HOST / ROBOT_PORT / ROBOT_NUM — TCS connection.
• JOINT_MIN / JOINT_MAX — joint soft limits. These are measured for one specific PF400. Yours will differ — sweep yours and update these. The script clamps targets to these bounds, but allows the robot to remain at out-of-range positions and only refuses to push further out.
• RATE — per-axis jog rate at full deflection (J1 mm/s, J2-J4 deg/s, J5 mm/s).
• DEADZONE — stick deadzone (0..1).
• TICK_HZ — command rate. 40 Hz is a good balance.
• TCS_PROFILE / TCS_MSPEED — motion profile and system master-speed. InRange=-1 enables continuous-path blending — this is what makes jogging feel smooth. Don't change it to a positive value unless you want the robot to decelerate to a stop after every commanded segment.

Mapping varies by controller (probably)

The NS2 Pro's HID layout is reverse-engineered, not documented. The bit positions in decode_buttons were verified empirically on one specific unit. If your D-pad fires the wrong joint or you get unexpected behavior:

python3 ns2_dpad_probe.py

It walks you through pressing each D-pad direction and prints the bit each one fires. Patch the four if hat & 0xXX: lines in decode_buttons to match.

For other buttons, set NS2_DEBUG=1 and watch the button bitmap as you press things:

NS2_DEBUG=1 python3 ns2_pf400.py

Why does the controller keep losing HID mode?

The init isn't persistent. The Switch 2 Pro Controller reverts to its native Nintendo protocol every time it loses power (USB unplug, battery dead, system sleep). Just re-run ns2_init.py whenever the script can't find the controller.

Smoothness — the boring details

If you've used a similar script before and it felt stuttery, three settings dominate:

1. InRange = -1 (blended motion) vs the default positive value. With a positive InRange, the controller decelerates to a near-stop at every commanded target, producing jerkiness when you stream commands rapidly. -1 lets segments flow into each other.
2. High accel (500 in the profile). Without it, the robot can't track rapid stick-direction changes.
3. mspeed 100. Many systems default to 50, which silently halves all profile speeds.

All three are pre-set in TCS_PROFILE and TCS_MSPEED.

Credits

• USB-mode init reverse-engineering by @dannydarvish in Switch2ProMac.
• Robot control loop and TCS protocol from the Precise Automation PF400 / TCP Command Server documentation.