P2 wireless HDMI transmission (WHDI)

TubularTubular Posts: 3,955
edited 2020-05-22 - 01:21:46 in Propeller 2
Yesterday I successfully tested using a 5.8GHz wireless HDMI sender with the Prop2

Happy to say got good results out to at least 15m line of sight, and ~8m through a concrete wall

These transmit using 5.8 GHz band. Jaycar have a special on these at the moment. There are various versions but I like these because of the compact transmitting dongle (rather than a desk mounted box)

I added a dual output Lipo chargepack for portable testing. There is something cool about having your whole setup battery powered, but viewing the output from Rogloh's DVI driver on a big TV across the room

I can't get Chip's hdmi spiral demo to work right just yet (it comes up distorted), but will dig deeper. It does work when directly driving the same TV used with this testing.



  • Very cool Lachlan. Streaming the P2 display remotely. This could be handy for robotics/machine applications too where a display is not attached directly to a device for various cabling reasons.

    Regarding Chip's demo vs DVI driver output working, it must be resolution/timing related somehow.
  • That's really neat! Wonder if there's a way to do Miracast...
  • Yeah I was wondering that too Rayman. There may be, but these are designed to be somewhat transparent to the signal they are transmitting, sometimes its nice not to need any software to make good things happen

    One other thing, they also send audio and extend an IR remote control. The audio helps us with the P2 since audio-over-hdmi is at early stage. But also wondering whether the IR channel could be repurposed for a serial transmission channel
  • roglohrogloh Posts: 2,256
    edited 2020-05-22 - 03:54:54
    How is the IR emitter output being done, and at what voltage? If the output voltage is designed for low drop IR LEDs it could even be attached directly, but that may not be the case. You could possibly clamp it with a zener in parallel to the input to emulate the IR LEDs and keep the input voltage limited but I guess the most compatible way might be to add a transistor & input resistor to feed into the P2 with a pullup enabled internally.

    It's be handy to emulate a mouse or other controller with cursor movement/mouse click etc using a GUI on the P2 via a control channel such as this. If you wanted it as a general purpose unidirectional serial channel it's likely to be very low bandwidth given how IR encoding works. You'd need some other device at the sending end to take your serial data from somewhere and modulate it into IR pulses too, but just about any micro could do that. One application there is a remote keyboard input via IR. Easy P1 project.
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