System Mode
AUTO manages pumps from sensors automatically.
Tank Selection
Tank Size (Ultrasonic)
Used to compute water level %
Cooling Fan (Test)
Fan Override
Force fan ON/OFF for testing
Communication Log
Waiting for connection…
💧
AquaCtrl
Version 1.2.0 · Bluetooth Water Level Controller
About This App
AquaCtrl connects wirelessly to your WLC-16U4-BT water level controller via Bluetooth LE.
It shows real-time water levels for two tanks, controls two pumps, and lets you change
modes, tank sizes, and force pump states from your phone. When no hardware is connected,
the app runs a live simulation so you can explore all features.
Hardware
MCU
ATmega16U4 @ 8 MHz
Bluetooth Module
KT6368A (BLE 5.0)
Baud Rate
115200 8N1
Inputs
Float switch + HC-SR04
Outputs
2 × relay + fan
Legal
This software is provided “as is” without warranty. Do not rely on it as the sole
safety mechanism for your water system. Always provide physical overflow protection
and inspect wiring regularly.
Getting Started
Connecting to the controller
1. Power on the controller. The MODE LED should be green.
2. Make sure your phone’s Bluetooth is ON.
3. Tap the Connect pill in the top-right corner.
4. Choose the device named
5. When connected, the dot turns green.
No device? The app runs a live simulation automatically.
2. Make sure your phone’s Bluetooth is ON.
3. Tap the Connect pill in the top-right corner.
4. Choose the device named
KT6368A.5. When connected, the dot turns green.
No device? The app runs a live simulation automatically.
Operating Modes
AUTO mode
The controller monitors both tanks and turns pumps ON/OFF automatically.
• Pump 1 uses the float switch.
• Pump 2 uses the ultrasonic sensor.
• Pump 1 uses the float switch.
• Pump 2 uses the ultrasonic sensor.
MANUAL mode & Force ON / OFF
Switch to MANUAL to reveal the Force ON and Force OFF buttons in Settings.
• Force ON pumps water regardless of level.
• Force OFF stops the pump immediately.
• Return to AUTO when done.
• Force ON pumps water regardless of level.
• Force OFF stops the pump immediately.
• Return to AUTO when done.
Tank Selection
Why tank size matters
The ultrasonic sensor only measures distance. To convert that to a
water percentage, the controller must know the tank’s height.
Choose the correct tank from Settings → Tank Selection.
Choose the correct tank from Settings → Tank Selection.
Reading the indicators
Water color meaning
The fill color is computed continuously from the percentage:
• Green — near 100 % (full)
• Yellow — around 50 %
• Orange — around 25 %
• Red — near 0 % (empty)
• Green — near 100 % (full)
• Yellow — around 50 %
• Orange — around 25 %
• Red — near 0 % (empty)
Status cards
Right side of each tank shows:
• Water level — dot color tracks the fill color
• Pump — glows green with ON text when running
• Tank — currently selected tank size
• Input — float switch or ultrasonic sensor
• Water level — dot color tracks the fill color
• Pump — glows green with ON text when running
• Tank — currently selected tank size
• Input — float switch or ultrasonic sensor
Simulation
What is simulation mode?
When no Bluetooth device is connected, the app simulates both tanks filling and draining
so you can preview all features. The header shows Simulation to remind you.
Connecting a real controller stops the simulation immediately.
Connecting a real controller stops the simulation immediately.
Troubleshooting
Cannot connect via Bluetooth
• Ensure the module isn’t paired to another phone.
• Restart Bluetooth on your phone.
• Move closer (within 5–10 m).
• Power-cycle the controller.
• Restart Bluetooth on your phone.
• Move closer (within 5–10 m).
• Power-cycle the controller.
Wrong water percentage
• Re-select the correct tank size.
• Verify the ultrasonic sensor is 20 cm above the max water line.
• Clean the sensor face.
• Verify the ultrasonic sensor is 20 cm above the max water line.
• Clean the sensor face.
Safety
Important warnings
• Mains voltage is dangerous — use a qualified electrician.
• Always provide physical overflow protection.
• Do not rely on Bluetooth alone for safety.
• Keep the controller dry.
• Always provide physical overflow protection.
• Do not rely on Bluetooth alone for safety.
• Keep the controller dry.