Patterndo Features

2D · 3D views and flipping sides

The default is the 2D view, with parts and wiring on a grid. Zoom with the wheel, pan by dragging with the middle button or holding Space while dragging, and press 0 to fit the whole board on screen.

Flip the board with the [Component side]/[Copper side] button at the top or the F key. On the copper side the board is mirrored left to right, so you see it in the same orientation you will have while soldering. The mirroring rules for the two sides are explained in Reading a Layout Diagram.

Press 3 (or the 3D button at the top) to open the 3D view, where you can turn the board to judge part heights and layout. Drag an empty area to orbit, drag with the middle button to pan, drag a part to move it, and press R to rotate it 90°. 3D uses WebGL, and in environments where it cannot be opened you are returned to 2D with a message.

2D and 3D views guide →

Parts and properties

Press A or [Add part] to open the list, search by name, and place a part. The supported parts are as follows.

With a part selected, the properties panel lets you change its value (resistors and capacitors), LED color, Zener voltage, a transistor's polarity and pin roles (E, B, C), the IC model, and more. Copy, cut, and paste (Ctrl+C Ctrl+X Ctrl+V) and rotation (R) are also supported.

Wires · jumpers · net aliases

• Wire (W): drag from a start hole to an end hole to draw horizontal, vertical, or 45° lines. If the direction does not line up, it bends once to connect. Where bare wires cross, they are treated as touching at the crossing.
• Jumper (D · J): places an insulated jumper that hops horizontally or vertically. It cannot be placed over a part body, and overlaps are marked as conflicts.
• Delete (E): each press cycles the delete scope through all → wires → parts.
• Linked move (Shift+Q): moves a part while keeping the wires attached to it.
• Net alias (C · N): puts a label like CLK on a wire to make the circuit easier to read. It is for display only, so giving two nets the same name does not connect them electrically.

As you draw lines, the holes and pins that are joined are worked out automatically as a net. The status bar at the bottom shows the name of the net under the cursor.

Live simulation

Press [Sim] at the top to analyze the circuit using the board's supply voltage as power. It calculates the voltage and current at each connection point and reflects LEDs lighting, seven-segment displays, and the HIGH or LOW state of IC outputs on screen. Parts whose state changes over time, such as 555 timers and counters, are updated by advancing time in small steps.

• Hover over an IC pin to see its pin name, voltage, HIGH or LOW, and output drive state.
• While simulating, click (tap) a wire or hole in the 2D view to open the net probe, which shows that net's voltage and the current flow (in and out) for each part.
• If there is an unsupported IC or the connections are incomplete, the sim is "blocked" and the reason is shown in a notice and the diagnostics panel.

Simulation uses ideal component models for learning and pre-checks. Its accuracy and limits are explained in the FAQ.

How to use simulation →

Diagnostics (DRC)

Patterndo continuously checks the circuit with 24 rules. They fall into circuit rules such as VCC–GND shorts and jumper conflicts, simulation rules such as missing connections, polarity errors, and part stress, and placement rules such as being outside the board, overlapping parts, and touching another net.

Results appear in the diagnostics panel at the bottom, as markers on the canvas, and as notices. You can change the display level of each rule (error, warning, info, or off), while critical rules such as a VCC–GND short are always fixed as errors.

How to read diagnostic messages →

Auto-rewire

[More → Auto-rewire] keeps the pin connections as they are, re-lays the whole board with inputs on the left and displays on the right, and recalculates the wires and jumpers. Jumpers never overlap or cross and are placed only within 10 holes, and if no result meets the conditions, the original is left untouched.

When it finishes, a summary shows the nets that changed, the nets that were kept, and the nets that failed. The result is recorded as a single step in the undo history, so one Ctrl+Z puts it back. If you edit the board while it runs, the result is not applied.

Auto-rewire guide →

Importing a schematic or netlist

Load a KiCad, EasyEDA, Altium (Protel), PADS, or SPICE netlist, or a schematic photo (PNG or JPG), in [More → Import schematic or netlist], and the connections you still need to make are drawn as dashed lines (a ratsnest) between board pins. Once you wire a connection, its line disappears, and each net shows whether it is complete and whether it looks shorted to another net.

• Place missing parts: resistors, capacitors, LEDs, and ICs that are in the netlist but not on the board are placed in free spots and matched in one go.
• Photo recognition: a draft that reads IC boxes, IEC resistor symbols, capacitor plates, and junction dots. For a more accurate read, use [Copy AI instructions], give the photo to a chat AI, and paste back the JSON it returns.
• Fixing: correct nets yourself with the select, link, and erase tools, and continue with auto-rewire using [Place as jumpers and rewire].

Schematic import guide →

Saving · sharing · RAW JSON

• Address saving: every time you edit, the current board is updated in the ?b= value of the address bar.
• Share link: [Share] creates a short address (/s/…). It is kept for 180 days from the last save.
• RAW JSON: in [More] you can download the board as a JSON file and load it again.
• Undo and redo: Ctrl+Z, Ctrl+Y

Saving, sharing, and backup guide →

Touch · pen input

The layout switches between desktop, tablet, and mobile by screen size. On touch, pinch to zoom, tap with two fingers to undo, tap with three fingers to redo, and long-press a part or wire to open a menu. In the pen settings you can choose whether drawing with the pen wires automatically, whether the pen's back end or eraser button switches to erasing, and what finger gestures do (move a part, pan, or the selected mode).

Shortcuts and command search

Keys that are easy to reach with your left hand are assigned to tools while your right hand stays on the mouse. Press ? to open the full list, and Ctrl+K to search and run tools and commands.

Shortcuts guide →

Board settings

In [Board settings] you set the board size (17 to 161 holes wide, 13 to 121 holes tall), the supply voltage, internal resistance, and maximum current, and the display level of the diagnostic rules. The defaults (62×28 holes, 5 V) are plenty to start with.