Airgap

one way. nothing here can talk back over the air.

What to send

Nothing loaded yet.

How to send it

Authentication

Not authenticated.

Firmware

The board is reset into its bootloader over the same USB cable, written a page at a time, and then read back and compared. If the readback does not match, it stops and says where.

Run

No board connected.

Readout

Load something to send, then press Send. The screen flashes and a sensor on the board reads it. Nothing comes back over the air, so this tool never claims a transfer arrived. Connect the board over USB if you want it to say so itself.

The eye

Connect a board and it draws itself while the board streams samples.

Rates on this profile

PatchesPayload B/s 64 bytes1 kB

About

AIRGAP transmitter

Gets data into a microcontroller with no network, no radio and no free USB port, by flashing the screen at a light sensor or chirping the speaker at a microphone. A provisioning channel, not a transport.

Copyright (C) 2026 M. B. Parks. Licensed GPL-3.0. No third party libraries are used or embedded: the protocol, SHA-256 and HMAC in this page are all written out in it.

Runs from disk. No server, no build step, no install.

Feedback and support