The **PiBot CNC Pendant V4.0** is a handheld controller that connects via Bluetooth or RJ12 to CNC machines with FluidNC and GRBL-HAL firmware. Developed by PiBot with software input from ESP3D creator Luc, it allows manual control and monitoring of CNC routers, laser engravers, and other systems based on GRBL/FluidNC. It can connect through a wired RJ12 or Bluetooth and has a capacitive touchscreen, an industrial-grade encoder, a potentiometer knob, a band switch, three independent switches, and a speaker, housed in a dual-PCB design enclosure for IO expansion. It communicates at 115200 baud over Bluetooth or up to 1,000,000 baud in wired mode and uses a flat-top 18650 battery with onboard charging and power level indication.
PiBot CNC Pendant V4.0 specifications:
– Main Controller: ESP32
– Storage: MicroSD card (future one-click upgrade)
– Display: Capacitive touch screen (approx. 3.5 inches)
– Audio: Built-in speaker
– Connectivity:
– Wired: RJ12 port
– Wireless: Independent Bluetooth TX/RX modules
– USB: 1x USB Type-C port for updates and charging
– Misc:
– 3x Independent physical switches
– Industrial-grade encoder
– Band switch
– Power switch
– Boot and reset button
– Indicator light function button
– Battery level indicator LED
– Potentiometer knob
– Power:
– 5V from USB-C
– 18650 flat-top battery (not included)
– Charging circuit
– Dimensions: 165 x 60 mm
– Weight: 365g
– Enclosure: 3D-printable casing (STL files provided)
**Manufacturer Warning:** Do not insert the 18650 battery when using the RJ12 wired connection to avoid damaging the ESP32 chip due to a voltage imbalance. The battery is intended for Bluetooth use only.
**Note:** GPIO25 and GPIO27 are used, so the pendant cannot be used simultaneously with 0.96-inch OLED displays on most FluidNC controllers.
The pendant is pre-installed with firmware set to 115200 baud, making it “plug-and-play.” It is compatible with FluidDial (CYD button version) and works with FluidNC v3.9.7+ after configuring UART pins (GPIO25 and GPIO27) in the YAML file. A PiBot UI co-developed with the ESP3D author will soon support microSD card upgrades. The firmware is open-source, though the hardware is not fully open-source, except for the enclosure STL files.
A safety and performance issue was noted by Lumen Works Engineering regarding buffer overloading from the encoder wheel, possibly causing stalled movements or crashes. To address this, they developed a custom FluidDial firmware fork for the PiBot, resolving the buffer issue and enabling additional features like a 4-position band switch and potentiometer-based jog speed control. The modified firmware is available on the Fluiddial repo.
As the pendant supports CNC controllers with FluidNC firmware, it could work with the 6x CNC Controller and TMC2209 Pen/Laser CNC Controller, but using a PiBot CNC router controller is recommended for best compatibility.
The PiBot CNC Pendant V4.0 is priced at $70.58 on AliExpress and $79.99 (discounted from $99.99) at the PiBot Store, with the package including the main unit, two Bluetooth TX/RX modules, a Bluetooth adapter, an RJ12 module, and a 1-meter communication cable.