pyautogui's Quartz-based keystroke path often fails on newer macOS because the Python CLI binary doesn't auto-surface in System Settings > Accessibility. User reported the daemon detected taps fine but keystrokes never landed in any window. Switch to AppleScript / System Events on macOS. Permission attaches to whatever terminal/app launched the Python process (Terminal.app, iTerm, etc.) — a familiar named app the user can grant Accessibility to in one click. Combined keystroke + Return in a single osascript call to keep latency ~100ms per tap. Fall back to pyautogui if osascript fails (handles edge cases) and on non-macOS platforms.
fusion_clock ACR122U Wedge
Turns an ACR122U (or any PC/SC ACS reader) into a USB-HID-style keyboard wedge so the fusion_clock NFC kiosk can use it.
Why this exists
The ACR122U is a fantastic 13.56 MHz reader (better range than cheap HID readers, reads MIFARE Classic/DESFire/NTAG/FeliCa/ISO15693 — basically everything Ubiquiti UA-Pockets and most enterprise cards). But it speaks PC/SC (CCID), not HID keyboard. Browsers can't talk to PC/SC devices directly.
This daemon bridges the gap: it polls the ACR122U over PC/SC, reads tag UIDs, and types them into the focused window as keystrokes — exactly like a USB-HID reader would. The fusion_clock kiosk page's existing keyboard listener picks them up the same way.
ACR122U → PC/SC → wedge.py → keystrokes → kiosk page in Chrome
Setup
macOS
brew install swig
pip3 install -r requirements.txt
python3 wedge.py --verbose
The first time the daemon tries to type a UID, macOS will pop up an Accessibility permission prompt. Grant it to Terminal.app (or whatever shell ran the script). This is one-time.
If pyscard fails to install: ensure Xcode command-line tools are installed (xcode-select --install).
Windows
pip install -r requirements.txt
python wedge.py --verbose
No swig required — pyscard ships pre-built wheels on Windows.
Linux
sudo apt install pcscd pcsc-tools libpcsclite-dev swig
sudo systemctl enable --now pcscd
pip3 install -r requirements.txt
python3 wedge.py --verbose
You may need to run with sudo or add your user to the plugdev group.
Usage
# Quiet mode — just types UIDs on tap
python3 wedge.py
# Verbose — prints every tap and reader event
python3 wedge.py --verbose
# Detect-only — prints UIDs but doesn't type them
# (use this to verify the reader is working before granting Accessibility perms)
python3 wedge.py --no-type --verbose
Output format
UIDs are typed as colon-separated uppercase hex, followed by Enter:
04:10:5B:CA:FD:22:90<Enter>
This matches what FusionClockNfcKiosk._normalize_uid() expects, so the kiosk recognizes it without any server-side translation.
Debounce
The daemon won't re-emit the same UID more than once within 2 seconds (so holding a card on the reader doesn't fire repeated clock-ins). Tap a different card, or wait 2 seconds, and the same card will re-emit.
Running as a service
For kiosk deployments, you want this to start at boot and stay running.
macOS — LaunchAgent
Create ~/Library/LaunchAgents/com.nexa.fusion-clock-acr-wedge.plist:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>com.nexa.fusion-clock-acr-wedge</string>
<key>ProgramArguments</key>
<array>
<string>/usr/bin/python3</string>
<string>/Users/USERNAME/path/to/wedge.py</string>
</array>
<key>RunAtLoad</key>
<true/>
<key>KeepAlive</key>
<true/>
<key>StandardOutPath</key>
<string>/tmp/fusion-clock-wedge.log</string>
<key>StandardErrorPath</key>
<string>/tmp/fusion-clock-wedge.err</string>
</dict>
</plist>
Load it:
launchctl load ~/Library/LaunchAgents/com.nexa.fusion-clock-acr-wedge.plist
Windows — Task Scheduler
Create a task to run python wedge.py at login. Or use NSSM to install it as a Windows service.
Linux — systemd user service
Create ~/.config/systemd/user/fusion-clock-wedge.service:
[Unit]
Description=Fusion Clock ACR122U Wedge
After=graphical-session.target
[Service]
ExecStart=/usr/bin/python3 /home/USER/path/to/wedge.py
Restart=always
[Install]
WantedBy=default.target
Enable it:
systemctl --user enable --now fusion-clock-wedge.service
Troubleshooting
"No PC/SC readers detected"
- macOS: PC/SC is built into the OS, no service to start. Just make sure the reader is plugged in.
- Linux:
sudo systemctl status pcscd— make sure it's running. - Windows: built-in.
"pyautogui can't type on macOS"
- Grant Accessibility permission to your terminal in System Settings → Privacy & Security → Accessibility.
"Reader detected but no UID on tap"
- Try
--verboseto see error messages. - The card might not respond to the standard GET_UID APDU. Most 13.56 MHz cards do; some FeliCa variants don't.
- Try
python3 wedge.py --no-type --verboseto confirm detection works without involving the keyboard layer.
Keystrokes appearing in the wrong window
- pyautogui types into whatever window has focus. Make sure the kiosk page is focused when you tap.
- This is the same behavior as a USB-HID reader — they both depend on the OS focused window.
Future packaging
This is the prototype. For client distribution we'll wrap it in:
- macOS .app bundle (PyInstaller + py2app)
- Windows .exe (PyInstaller)
- Linux AppImage
Plus autostart and an idle "no reader detected" status indicator. See parent module's todo list.