Ultrasonic Relay Switch
Monitor and calibrate your board
Plug the board into this computer with its USB cable and press Connect device. Everything runs inside your browser. Nothing is uploaded anywhere.
- Plug inConnect the board with a USB data cable.
- Pick the portChoose FT232R USB UART (Windows: a COM port) in the browser list.
- Wait 2 secondsThe board restarts when it connects. The relay stays off.
Firmware update needed
The update is a one-time step done with the Arduino IDE (see the README, section "Updating the firmware"). After updating, connect again.
Help: connecting on Windows
1. Use Chrome or Edge
Web Serial works in Google Chrome and Microsoft Edge (version 89 or newer) on Windows, macOS, Linux and ChromeOS. Firefox and Safari do not support it.
2. Driver for the USB chip
The board uses an FTDI FT232R USB chip. Windows 10 and 11 usually install the driver automatically through Windows Update within a minute of plugging in.
If the board does not show up, install the FTDI VCP driver from ftdichip.com/drivers/vcp-drivers (Windows "setup executable"), then plug the board in again.
3. Find the COM port
Open Device Manager (right-click Start) and expand Ports (COM & LPT). You should see USB Serial Port (COM3) or similar. Pick that port in the browser list.
4. Port busy?
Only one program can use the port at a time. Close the Arduino IDE Serial Monitor, PuTTY, other browser tabs with this app, and try again.
5. Good to know
Connecting restarts the board (about 2 seconds). This is normal and the relay stays off during the restart.
Live view
IdleThe 3D view is not available on this computer (WebGL is turned off). All readouts and settings still work.
Readouts
- Trigger distance
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- Hold time
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- Hysteresis
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- Settings from
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- Signal quality
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- Knob 1 / Knob 2
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- Connection
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- Firmware
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Distance chart
Put a flat object (a book, a board) at a distance you have measured with a tape, straight in front of the sensor. Then capture for a few seconds. The app shows how steady the reading is and can correct the sensor.
| Reading |
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Correct the sensor
Use this distance as the trigger
Sets the trigger to the measured distance plus a margin and switches to software values.
Some knobs do not reach the very ends of their range. Press Start, turn each knob all the way left and all the way right, then press Apply. The full knob travel then maps to the full 5 to 200 cm and 1 s to 1 min.
Knob 1 - distance
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Knob 2 - hold time
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Relay pulse
Switches the relay ON for a short time, then OFF. A connected load (light, motor, lock) will switch too. Not possible while an object holds the relay ON.
Status LED
Blinks the LED fast for 2 seconds so you can find it on the board.
Profiles keep complete setups (mode, distance, hold, hysteresis, sensor and knob correction) in this browser.