Draft: transmitting with esp8266

[devkral]

esp8266 can transmit now.

Not 100% sure that this works. You might want to test it.

[peterhinch]

From the docs:

ESP8266 is unsupported; it seems incapable of generating the required signals.

I spent some time studying this and drew the above conclusion. By all means feel free to experiment, but unless there is some specific firmware improvement I feel disinclined to revisit this.

[devkral]

but maybe machine.bitstream(...) could do the wonder. I tried but failed.

[peterhinch]

There are a few challenges: machine.bitstream() assumes a sequence of bits, each encoded with the same timing. IR sequences generally start with a preamble with special timing. Also you need a way of implementing the 38KHz carrier. This can be done with PWM, with the modulation done with a simple external circuit.

A generic solution - i.e. one supporting all the protocols - would need some thought.

[EDIT]
From the docs

The transmit method is synchronous with rapid return. Actual transmission occurs as a background process...

As I understand it machine.bitstream() is a blocking method. This would make it impossible to conform with this requirement.

However if you're happy with writing a blocking method for a single protocol I think a solution using machine.bitstream() and PWM is feasible.