Circuit Editor

The circuit editor is the canvas in the simulation panel. Every project starts with its board on the canvas; you add parts and connect them with wires.

Working with parts

Adding parts

Click the blue + button at the top left of the simulation panel (next to the Play button).
Browse the categories or type in Search parts... (names and keywords work, for example temperature or i2c). Press Enter to add the first result.
Click a part to place it on the canvas. The view zooms out if needed so the new part is visible.

Moving parts

Drag a part to move it. When you drop a part on a breadboard, its legs snap to the nearest holes.

Selecting a part

Click a part to select it. The part toolbar appears with the options for that part:

Option	Parts
Color swatches	LEDs, buttons, LCDs, wires and more
Value list	Resistor values, capacitor values, logic analyzer range
Sliders	Sensor values such as temperature, humidity, distance, light, gas or weight
Text field	Notes, RFID card UID
Message box	HC-05 Bluetooth: send a message from a virtual phone
Card contents	microSD: files written by your program
Rotate (R)	All parts that can rotate
Flip	Parts that can be mirrored
Delete	All parts except the board

While a part is selected, the hint bar at the bottom of the canvas shows its wiring hint, for example which board pins an I²C display needs.

Rotating and deleting

Press R to rotate the selected part by 90°.
Press Delete (or Backspace) to delete the selected part or wire. Wires connected to a deleted part are removed too. Click Undo in the message that appears, or press Ctrl + Z, to bring them back.
The board itself cannot be deleted.

Working with wires

Drawing a wire

Click a pin. All pins on the canvas are highlighted while you draw.
Optionally click empty spots on the canvas to add bends.
Click the destination pin to finish.

While drawing, press Backspace to remove the last bend or Esc to cancel.

Editing a wire

Click a wire to select it. Then:

Action	How
Change the route	Drag the round handles at the bends.
Add a bend	Double-click the wire.
Move an end	Drag the blue dot at either end to another pin.
Change the color	Press 0–9, or pick a swatch in the toolbar.
Straighten the route	Click Straighten route in the toolbar.
Delete	Press Delete.

Wire colors

Breadboards

Breadboards (mini, half and full size) are in the Breadboard & Power category. When a part's legs sit over breadboard holes, they connect automatically, just like pushing a component into a real breadboard:

The five holes in each column of the top half (rows a–e) are connected, and so are the five holes in each column of the bottom half (rows f–j).
The half and full breadboards have power rails at the top and bottom; each rail (+ and −) is connected along its whole length.
The gap in the middle separates the two halves, so chips and modules can straddle it.

In diagram.json, breadboard holes are named by column and row, for example 12t.a (column 12, top half, row a) or 5b.j. Rail holes are named tp.3 (top +), tn.3 (top −), bp.3 (bottom +) and bn.3 (bottom −).

Draw wires from board pins to any breadboard hole to bring power and signals to your parts.

Navigating the canvas

Action	How
Zoom	Scroll the mouse wheel, or use the + and − buttons.
Pan	Drag an empty area of the canvas.
Fit to view	Click Fit to view, the third zoom button.
Deselect	Press Esc or click an empty area.

Editing the circuit as text

Everything on the canvas is stored in diagram.json. Open the diagram.json tab to edit positions, colors or wires directly; valid changes are applied immediately. The format is described in diagram.json Format.

Ready to try it?

Start simulating free