HotWireCNC

DroidForks

About this app

Control your hot-wire foam-cutting CNC machine directly from your phone. HotWire CNC connects over USB to any 2- or 4-axis machine running grblHAL firmware and gives you full jogging, G-code streaming, and live machine feedback — no laptop required at the machine.

CONNECT
• USB Host connection (CDC-ACM, CP210x, CH340, FTDI)
• Selectable baud rate
• Raw command console with full history, color-coded by response type

JOG
• X/Y pad, plus a second-tower pad (A/Z or U/V) on 4-axis machines
• Synchronized jog — move both towers together in a single command, not two sequential ones
• Per-axis Home buttons, gated behind a Settings checklist so you can't fire a homing command at an axis you haven't confirmed has a switch wired
• Configurable step-size and feed-rate presets, separate for metric and imperial
• Live feed-rate warning compared against your board's actual Max Rate setting
• Buttons and jog pads scale up automatically on tablets instead of staying phone-sized

RUN
• Load G-code from your phone, or push a file from a PC over Wi-Fi (no cable needed for transfer)
• Live 2D trajectory preview for both axis pairs, drawn to one shared scale with a coordinate grid
• A live position marker tracks the machine's real reported position — not just how much code has been transmitted
• Estimated run time with a live countdown that adjusts automatically to your feed-rate override
• Feed-rate override and wire-power control, plus a manual Wire ON/OFF override for quick physical control
• Choice of streaming protocol: simple line-by-line, or classic character-counting for higher throughput on files with many short segments
• Reverse path — re-traces the loaded toolpath end-to-start with one tap, correctly recomputing arc geometry and keeping each section's original speed and wire on/off state
• Edit the loaded G-code directly on your phone and save the result to a file of your choice
• Tap any line to run from exactly there, or resume automatically from the last stop point after a board error or lost connection — always a deliberate, confirmed action, never silent

SETTINGS
• Axis count auto-detected on connect
• Full grblHAL $$ settings editor — read, edit, import/export from a file, or bulk-apply Machine Limits and Acceleration per axis
• Invert axis/homing direction, and limit-switch polarity, with one tap
• Board info (firmware version, compiled options)
• All preferences are saved automatically and restored next time you open the app

RUNS IN THE BACKGROUND
The USB connection and any active cutting job keep running if you switch apps, take a phone call, or the screen turns off. A persistent notification shows live status with Pause/Stop controls.

WHAT YOU'LL NEED
• An Android phone with USB Host (OTG) support and a USB-OTG cable
• A grblHAL (or compatible grbl) controller board with a USB-serial interface

This app is built for people who already have a hot-wire CNC machine and controller — it does not include, sell, or require any particular hardware brand. A couple of advanced fields (Hot Wire start-power and relay commands) are a best-effort implementation and may need verification against your specific firmware build before you rely on them.

No accounts, no ads, no analytics, no data collection of any kind — everything runs locally between your phone and your machine, or over your own Wi-Fi network for file transfer.

What’s new

First public release of HotWire CNC — USB control for grblHAL hot-wire foam cutters.

• Jog, synchronized dual-tower jog and per-axis homing
• Load G-code from your phone or over Wi-Fi, with live trajectory preview
• Feed-rate override, PWM wire power, run-time estimate
• Edit, save and reverse G-code paths; run from any line or resume after a stop
• Full grblHAL $$ settings editor