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Fez VNC


#1

The Fez Domino doesn’t come with a display. I was wondering if it would be possible to implement a simple VNC-style server on the Fez.

Basically it would take the Bitmap frame buffer and instead of outputting it to LCD, output it over USB or Bluetooth so it can be viewed on a VNC client. It would be pretty simple to use a VNC client on a phone to have a remote graphical window into the Fez.

Anybody think this could work and worth doing?


#2

Hi realiser ,

you should have in mind , that the modules are not modern style Quad-core , 32GB ram machines.

I think it is easier to add a SPI-display instead to burn the whole processing power for VNC.

But when it works , it looks very nice :smiley:


#3

I love the VNC idea and was going to implement it myself actually, just never got to it.

Sounds good but did you do the math? For a 16-bit color 640x480x2 = 600KB!!! That is about half a megabyte just for buffer :wink: You can still do VNC but then you need to generate the graphics on the fly instead if using buffer.

Or, use FEZ Cobra. It certainly has enough memory to do VNC


#4

Although the protocol may be ok, I would wait until GHI has integrated firmware level support for Ethernet. I have been using a modified GHI Ethernet driver for my Enet shield, and although it works, your code would be more portable if you waited.


#5

The math actually isn’t bad. You don’t have to run 640x480 at 24 bit - you can run 160x160 with black and white for example - that’s like a 3.5k frame buffer. What more do you need to show a few status boxes or maybe a remote oscilloscope display?

The compression schemes for VNC is very simple but effective… Once the initial frame is transmitted, only changes are sent after that - down to 4x4 pixel tiles if you want it to. Even if you don’t output to VNC, RFP is still and interesting protocol to implement… Instead of outputting every frame over SPI, output just the differences. Less CPU and less power too.

Ethernet will be ideal, but I think this can be done easily down to Bluetooth level, which can do over 1Mb/s. It won’t play full motion video, but it sure will work for simple graphical display updates.

What I’m after here is to use the power of the Presentation classes, which are there anyway, but with a screen a little distance away (maybe a phone). I have this image of a phone “looking” at the embedded device and seeing into it’s display. A window into the soul of a device :slight_smile:

I guess it should be possible to develop a “real” display driver and capture and transmit graphic primitives, but that’s beyond my current abilities.


#6

[quote]What I’m after here is to use the power of the Presentation classes, which are there anyway, but with a screen a little distance away (maybe a phone). I have this image of a phone “looking” at the embedded device and seeing into it’s display. A window into the soul of a device
[/quote]

FEZ Domino/Mini (USBizi) doesn’t have native graphics support (no windows no bitmap…) but FEZ Cobra (EMX) has native graphics support. So, to use any “native” NETMF graphics you will need FEZ Cobra


#7

Mmm. I haven’t considered that. I assumed because a “Fez” project runs on the emulator, it will run on the board too - minus an actual display output of course.

Is supporting the Presentation classes a firmware or hardware thing?

Anyway, I just got here and I don’t already want to get you guys’ back up, but something needs to be said…

The Cobra board, priced at $250 is just not worth it. Not for what I’m using Fez Domino for anyway. For that money one can get a full blown Windows CE machine with a 7" LCD. For the price of just the Cobra board, one can get an ARM board running CE (or Linux) with a touchscreen LCD.

I thought the point of Micro Framework was to be micro? Lighter than CE and Sub $100 at most. This was supposed to be a platform to build watches on… like the TI EZ430-Chronos (who I think got the pricing right).

Now, Fez Domino is pretty darn close - so there you get a lot of bang for your buck in the “Arduino” market. At $50 I reckon you’d probably wipe it out because it would be stupid to pay $25 for a hobby toy if you could build a real product for $50. I paid the money because finally I could get all the peripherals and productive development environment for a sub $150 device I’m building. It would be cheaper to build it with a PIC - but now I can do so much more. I’m very excited about using Fez Domino as a basis for rapid prototyping solutions - but Cobra, not so much.


#8

Correct, EMX module is about $75! Take that module and drop on your circuit and you are good to go. Using FEZ is much much much easier than using anything in the embedded market, no linux nor CE nor anything else would beat FEZ simplicity. Anyone who used FEZ would tell you the same thing :wink:

The $150 is for the FEZ Cobra board, but all this is optional. We give you the design files so you can make your own! Then the LCDs + enclosure are all optional.

Plus depending on your application, CE/linux may not be an option. There are cases where CE or linux is the right fit and NETMF is a bad idea and other applications where NETMF fits perfectly and using CE/linux would be a bad idea.