IRR BlocksIoT & Robotics Rwanda
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Water Tank Level Indicator

Build a water tank level monitor using a rotary potentiometer as an abstracted depth sensor. Illuminate a Red alert LED when reservoir fullness is below 20%.

Water Tank Level Indicator

Objectives

  • Wire a 10 kΩ potentiometer to 5V, GND, and analog pin A0.
  • Wire a 330 Ω resistor and Red alert LED to digital pin D8.
  • Program the alert LED to turn ON below 20% fullness and OFF at 20% and above.

Expected behavior

The Red alert LED turns ON when water fullness drops below 20%, and stays OFF at 20% or higher.

What this simulation can and cannot show

Educational abstraction: the potentiometer models a float sensor in normalized percentage (0–100%, not liters). The LED is an alert indicator, NOT a motorized pump or water valve.

Choose how to start

Start blank to place every part yourself, or load the starter: board, breadboard, resistor, LED and an unbound blink program. You still insert parts, make each connection and bind the blocks.

Build steps

0 / 10 steps complete

  1. Place UNO R3 (Not yet)

    Provides 5V, GND, A0 and D8.

  2. Place breadboard (Not yet)

    Houses the potentiometer and alert LED.

  3. Insert 330 Ω resistor (Not yet)

    Limits current to the alert LED.

  4. Insert pot & LED (Not yet)

    Insert the 10 kΩ potentiometer and Red LED into breadboard strips.

  5. Wire potentiometer (Not yet)

    Leg 1 to 5V, leg 2 to GND, and wiper to pin A0.

  6. Wire D8 to LED (Not yet)

    Wire digital pin D8 through the 330 Ω resistor to the Red LED anode (+).

  7. Return cathode to GND (Not yet)

    Return the Red LED cathode (−) to GND.

  8. Build decision loop (Not yet)

    Read potentiometer; if level < 20% turn alert ON, else OFF.

  9. Bind blocks (Not yet)

    Bind analog read to the potentiometer and write blocks to the alert LED.

  10. Observe level boundary (Not yet)

    Verify that simulated levels below 20% trigger the alert and ≥ 20% clear it.

Lesson check

Run the circuit when every build step is done. Completion needs three observed ON/OFF cycles with both one-second waits.

Cycles observed: 0 of 2

Completion is saved only in this browser. It is not synced to an account and is not a certificate.

Open the Code tab to read the generated C++: both delay(1000) waits appear inside the repeat loop. It is not compiled or flashed.

Hints
  • Connect the potentiometer outer legs to 5V and GND, and the middle wiper leg to A0.
  • Divide the analog reading by 10 to compare with 20% (or compare to ~205).
Bill of Materials
  • arduino-uno-r3-a000066 (v1) × 1 — Microcontroller board (5V logic)
  • fritzing-half-breadboard-420 (v1) × 1 — Half-size prototyping breadboard
  • potentiometer-trimmer (v1) × 1 — 10 kΩ rotary trimmer (simulated tank level sensor)
  • resistor-axial-series (v1) × 1 — 330 Ω LED current-limiting resistor
  • led-5mm-colour (v1) × 1 — 5mm red LED (low-water alert indicator)
Wiring Explanation

Connect UNO 5V and GND to the breadboard. Connect potentiometer leg 1 to 5V, leg 2 to GND, and wiper to pin A0. Wire digital pin D8 through a 330 Ω resistor to the Red LED anode (+), and return cathode (−) to GND.

Draft lesson and translations — fluent educator review pending.

Board inspector

This project has no board yet.

Add a supported board to check wiring, simulate and preview code. Physical compatibility is unverified.

Lessons keep their board. Use a free project to try another board.

Wiring checks

Limited virtual teaching rules — not physical safety certification or a general electrical solver. Passing wiring checks does not run code or award completion.

Draft explanations and translations — fluent educator review pending.

Wiring checks blocked

Error: 0 · Warning: 0 · Unsupported: 1

  • Unsupported · missing-board

    This draft has no programmable board.

    Repair hint: Add a supported board and connect its named terminals explicitly.

    Involved IDs

    Parts tray

    Planned boards and parts

    Shown for planning only. They cannot be added, simulated or exported yet.

    • Raspberry Pi Pico W · RP2040 · Not available yet · Planned gate C
    • Raspberry Pi Pico 2 · RP2350 · Not available yet · Planned gate C
    • Raspberry Pi 4 Model B · other RAM sizes and PCB revisions · Not available yet · Planned gate D
    • BeagleBone Black Wireless · Not available yet · Planned gate D
    • Analog temperature and water-level circuit inputs · Not available yet · Planned gate C
    • Motors, servos, other displays and SPI/UART bus modules · Not available yet · Planned gate C

    Terminal inspector

    None

    Connections

    Use these labelled controls instead of dragging or selecting small terminals. Wires cross without joining.

    No wires yet.

    Select a part, then drag it or use arrow keys to move it. In Wire mode, choose two terminals. Visual overlap never creates electrical contact; use the attachment form to occupy a breadboard hole.

    Limited circuit simulation for the published UNO R3 and ESP32-DevKitC V4 teaching profiles. Code view offers qualified C++ and JavaScript previews (plus MicroPython for ESP32) with wiring manifests, plus document JSON. No CPU, Wi-Fi or Bluetooth is simulated, and physical compatibility is unverified.

    Draft learning copy and translations — fluent educator review is still required.

    Guest circuit projects

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    Local save pending

    Draft explanations and en/rw/fr translations need fluent educator review.