wirenerd
← All Build Guides
Build Guide · Motor Control

Counter

Press a button three times to turn on a light — then wire a reset. The exact circuit to learn how counters behave.

Difficulty: IntermediateBuilds on: a simple input circuitLesson: read the theory →

What you’re building

L1L2/NCA1RSTBTNRSTA2C
Button (with actuator cap) pulses the counter at A1; a reset switch ties to RST; A2 returns to L2/N. The counter's contact turns on the light at the target count.

Parts to add

  • 1Power Source
  • 1Push Button NO
  • 1Counter
  • 1NO Contact
  • 1Light
  • 1Single-Pole Switch (reset)

Steps

  1. Add the parts

    Click Power Source, Push Button NO, Counter, NO Contact, Light, and a Single-Pole Switch (for reset). Spread them out.

  2. Set up the counter

    Click the Counter. When prompted, type a number for the target count (e.g. 3), then click it again and type a letter (e.g. C). Click the NO Contact and type C so it follows the counter’s output.

  3. Wire the count input

    To wire, click the first terminal (it highlights), then click the second — a wire connects them. Click empty space to deselect. The counter’s A1 and A2 are its input; each pulse on A1 adds one to the count.

    Power Source L1 Push Button (left)
    Push Button (right) Counter A1
    Counter A2 Power Source N
  4. Wire the reset

    Wire a switch to the counter’s RST terminal. Energizing RST clears the count back to zero.

    Power Source L1 Reset Switch (left)
    Reset Switch (right) Counter RST
  5. Wire the output circuit

    When the count reaches the target, the counter energizes its letter C, closing the C contact and lighting the lamp.

    Power Source L1 C NO Contact (left)
    C NO Contact (right) Light (left)
    Light (right) Power Source N
  6. Energize and count

    Click Energize. Press the push button and watch the counter climb: 1/3, 2/3, 3/3. On the third press the light comes on. Flip the reset switch to clear it back to 0.

  7. Remember: edge-triggered

    Holding the button down only counts once. The counter counts the moment the input turns on (the rising edge), so you must release and press again for each count.

✓ Test it

  • Press the button 3 times: on the 3rd press the light comes on.
  • Flip the reset switch: count clears to 0, light goes off.
  • Hold the button down — it only counts ONCE. Counters are edge-triggered: release and press again to count.
Tip: Pair a counter with a timer for batching: count parts, then time a sealing cycle. That is real automation.

Open the Sandbox and build it

Follow the steps above with the trainer open in another tab.

Open the Sandbox →