Getting started
A breadboard, a parts bin and a code editor in one browser tab. Nothing to install, and no account needed.
1. Open the editor
Open the editor. It starts with a circuit already on the board: a pushbutton wired to a red LED, and a 2 Hz clock blinking a green one. If you would rather know what everything on the screen is before you touch it, read the screen, part by part first.
2. Press Run
The green LED starts blinking and the readout in the header shows the simulated time and the speed. Hold the mouse on the pushbutton and the red LED lights. That is the real simulation: the kernel resolving nets and waking parts.
3. Wire something of your own
Open the part panel with + Part or the A key and drop a part on the breadboard so its pins land in holes. Drag from any pin or hole to any other to draw a wire; the corners snap to the grid and you can drag them afterwards. Press R to rotate a part and Delete to remove it.
The breadboard behaves like the real thing: five holes to a strip, the rails down each side, the center channel wide enough for a DIP chip to straddle. There is more on both halves of this in placing parts and wiring.
Sticky notes. The + Part panel opens with a Sticky note at the top of it. Click it for a note in the middle of the view or drag it where you want it, then type: double-click a note to open it again, or select it and start typing. Notes come in yellow, pink, blue, green and gray, drag about like a part, resize from the corner, and are undone, copied and deleted like anything else on the board. They are drawing on the board and nothing more: the simulator never sees one, so a board covered in notes runs exactly as it did bare.
4. Add a board and write code
Drop an ESP32-C3 or an Arduino Uno on the canvas. The editor's right-hand pane becomes that board's project: a sketch plus any headers and extra sources you add, exactly as a real project has. Each board in a diagram has its own files, and they travel with the project.
5. Compile and run
Press Run. Your sketch is compiled in the tab with a real clang, and the resulting firmware executes on our own CPU core while the circuit responds to it. The first build streams the toolchain once and caches it; after that it is local. See the code editor and compiling.
6. Save and share
Everything is kept in the browser as you work, so closing the tab loses nothing. An account adds two things: your projects saved to the cloud so they follow you between machines, and a link you can share. Make one from the sign-in page, or keep going without one. The detail is in saving and autosave and sharing a project.
In a live collaboration the people in the room show as faces at the top of the canvas and as bubbles under the project name. Press one and your view follows theirs: pan, zoom and all, so what is in the middle of their canvas is in the middle of yours whatever size your window is. A pill says whose view you are on with a Stop in it, and moving the canvas yourself (a pan, a zoom, a pinch, a drag, a key) stops following as well, so you can take your view back at any time. The person being followed sees how many people are on them, and while their pointer is over the canvas you see it as a soft ring, which is what makes "look here" work. If you own the project there is a Bring everyone here button that asks the room to follow you once; anyone can stop the usual way. Nothing about following changes the circuit, and the simulation stays yours.
Assigning one to a class
A class assignment is a circuit of yours that every student opens their own copy
of (/class/<id>, Assign work). Before you assign it you can hold the parts
of it they are meant to build around: select them and press Lock in the
properties panel, or use Lock all in the canvas menu, and a small padlock sits
on each one. In a student's copy a locked part or wire cannot be moved, rotated,
deleted, rewired or have its properties changed, while everything else still
works: they add their own parts, wire into the locked pins, run it and read all
of it. Lock the code, in the same menu, does the same for every board's files:
the sketch is there to read and to run, not to edit. You can always unlock your
own project, and so can any teacher of the class you assigned it to; a student
cannot, not even in the copy they own.
What to read next
- Your first project in five minutes: an LED, a resistor, a board and eight lines of code.
- What Mokxi simulates, and what it deliberately does not.
- Every part on the bench, and the boards.
- Teaching with it: the twelve week course, week by week, and what a class needs before it can start.