Phone torch (Flash Force)

Confirmed on a Micro Scout.

The simplest emitter there is: the phone's camera torch blinks the VLL pattern at the brick's sensor. No hardware, no soldering, nothing to buy.

This is the Micro Scout Torch page on the site. It works in iPhone Safari as well as Android Chrome: iOS has no Web Bluetooth, so a torch is the only route to a LEGO brick from an iPhone. The torch comes from getUserMedia plus applyConstraints({advanced:[{torch:true}]}), and the page has to be served over HTTPS.

The catch, and the control that answers it

Browser timers jitter. VLL survives it because the protocol reads the ratio between light and dark rather than absolute times, but not infinitely, so the page carries a timing scale. It works from 1.05 to 1.35, and 1.2 is the default. Turn it if a brick will not listen.

Code Pilot and Scout decode the same codes, so a torch should reach them too. Untested: only the Micro Scout is confirmed.

When to use something else

For timing you can rely on, use lego-blockly or IR LED (invisible VLL). For a steady light with nothing to build, use Powered Up hub (Pybricks VLL).

Links

• adriansieber — Control LEGO via Swift on iPadOS, the project this engine is a port of.