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Unsure what to buy


I’m planning to make my first steps into the GHI Fez boards world, but I’m unsure which components to buy.

What I want to do, is provide the 7" touch screen and develop a (pretty) UI on it, fancy graphics and the likes. This would be powered by the Cobra board and talk over Ethernet to a webservice running on my machine, doing various operations.

So for sure I’ll be needing the following:

Touch Display:

Things I’m unsure about:

  1. What do I need when I don’t want to communicate over wired Ethernet, but want to use Wifi?

  2. Is the Cobra fast enough to render video from a stream?
    -> My idea is to hook up IP camera’s to it as well, in the UI you select which camera, and then you see what the camera is seeing.

  1. You need this to use wifi or you can a wifi-ethernet bridge

  2. Depends! You can connect an IP camera and get 320x240 image on the screen every couple seconds but you cant stream MPEG video for example. ChipworkX, which is 6 times faster, can play 320x240 MPEG2 at 30fps. Either way, NETMF is not made to be a “media player”, android is better for that. On the other hand, NETMF lets you control the hardware very easily, from graphics and networking to IOs and peripherals, much easier than android.

  1. Do you have any idea when this “Wifi Expansion replacement” is planned? Seems silly to buy one now if the new one is around the corner :slight_smile:

Am I correct that with the WiFi-Ethernet Bridge you loose your USB port? Does the ChipworkX have an extra USB port? Or some other way to get an extra usb port on the Fez Cobra

  1. How much more difficult is it to work with the ChipworkX compared to the Fez Cobra? I agree it’s not a media player, my goal isn’t watching high quality video either, but stuff like “Who’s at the front door”, or displaying a stream from a camera at a different location (example, watching office workspace from touchscreen at home)

2b. Does the Display TFT easily integrate into a ChipworkX? I saw that the Fez Cobra can easily be attached at the back of the 7" display, and looks like it has been designed for each other.

  1. no set dates yet but it is not going be in few days.
    No you do not lose a port. It doesn’t need USB all together! It is only needed when configuring the bridge on a PC.

  2. It is easy for an electrical engineer. If you do not know what is “5V tolerant” and not comfortable with soldering iron then I suggest you stick with Cobra.

2b. It is not made for ChipworkX but see this

  1. Ah, that’s good to know, was worried about no USB :slight_smile:

  2. So Cobra is more plug-n-play and with the modules (ChipworkX and EMX) you have to solder stuff together?

2b. I noticed that post too, it talks about the LCD signal, but does that hack also give you touch support?

  1. Cobra is a great functional expansion board (plenty of IOs exposed in easy to use ways) with an EMX module on it.


Ok, I guess I understand, when I have developed something on the FEZ Cobra, and I’d like to port it to the EMX, I’d have to buy an EMX and assemble various parts to it (something I’ll probably not do, since I’m no electrician :p)

Another little question:

When I buy the FEZ Cobra, I read it needs 5V to be powered. Does the FEZ Cobra come with something to draw 220V from an outlet and convert it to 5V? Or do I need to buy something separately?

(During development I’d like to just plug it into European 220V, and when development is done, I’ll find some other source in the house cabling :p)


kind of. But kind of not :slight_smile:

The EMX is truly a module, it’s something you would probably design a PCB to put it on, you could hardly ever consider it something standalone. Without the extra parts that exist around the module (in a Cobra or another development board) it will function but is hard for instance to connect any external devices to. Check out image 3 and 4 in the EMX module, and if you then check out image 1 in the Cobra you can see what I mean - the little pads on EMX/3 are the parts that are soldered to the Cobra mainboard in Cobra/1.

EMX module
Cobra mainboard

The code is exactly the same - it all runs on an EMX. So you don’t have to port your code to anything. You might have to be careful about the new hardware you build, since for instance unless you add the SD card holder, you couldn’t expect the new device to support using that.

The comparison that I would make is you would either buy a Cobra or an EMX Development board, you would not buy an EMX module on its own.EMX Dev board at $300 vs Cobra at $150, plus a display and holder.

You can probably consider the Cobra as a fantastic development board, or the EMX Dev board as a different dev board that has a different set of features. In my eyes the Cobra is a fantastic platform to start on, with a great range of flexible options for things like displays and device connections. The EMX Dev is a fixed screen option.

Edit: Here’s the power info.
All these devices will work when powered via USB. Plug it into your PC and away it goes. The bigger screens though draw more power than the USB can reliably deliver, so you need to use a power-pack. The device comes with a USB cable, but not a power-pack. In the US they call them wall warts, we (in AU) just call them power-packs or plug-packs. There’s a sticky thread on optimally powering these devices - You should get a suitable power pack - electronics shops usually have something suitable, Just remember the current draw is important.


I see, thanks for the info. Guess my option is a FEZ Cobra then, since I want the 7" touch screen and won’t design my own PCB :slight_smile:

I’ll have a look at that power options thread to see what I need

I guess in conclusion I’ll need:

  • FEZ Cobra
  • 7" TFT Touch Display
  • WiFi Expansion
  • Some way to power it

If I read it correctly from the power thread, I can get away with powering 6V through any convertor bought in a DIY store?

(And a stupid question, since English isn’t my native language, when the term ‘regulated 6v’ is used, what does the regulated mean? Can’t find much on Google :confused: is regulated = DC?)



European customer :wink:

#12 2nd item on that page is what you need (in europe)


What’s the difference between ACDC5012 and ACDCU1 on that page? Isn’t the “stabilized” 5V a better thing for the FEZ Cobra?


Follow-up on that comment:

When I read this brochure:

It says:

If you are connecting a TFT display then
definitely 6V only. You do not need
regulated 6V so any transformer should

If you have REGULATED 5V and want to
use that then solder a wire between VIN
and 5V on the expansion header. Again,

So, shouldn’t I have something that outputs 6V instead of that ACDC5012 which outputs 5V?

(I’m a newbie when it comes to electrical stuff, C# programmer :p)

When searching around I found this:

specifiec voltage / measured voltage with multimeter (MASTECH MY64):

3V / 3.26V
4.5V / 4.57V
5V / 5.03V
6V / 6.00V
7.5V / 7.59V
9V / 9.02V
12V / 12.02V

So does that mean when I buy the one you linked, I select 6V and plug it into the FEZ Cobra, or 5V? (since the image in the FEZ Cobra brochure says 6V in, but forum posts constantly mention 5V, confusing)


It never says 5V anywhere for the power connector. 5V is taped internally right on the 5V power line.

Use 6V


The ACDCU1 is good.

All you need is 6volts.

If you have a powered USB hub then you should be able to get away using just a USB connection to the hub.




Thanks, that’s a clear answer :slight_smile:

Guess I have everything for my initial shopping list now, thanks for the help :slight_smile:

Now I just need to read up a little on Z-Wave vs XBee and C# / FEZ Cobra integration, I saw an XBee module, but nothing for Z-Wave.


z-wave is not something I’d suggest you look at in netmf. whether you look at it at all is also something I question… If you’re interested in z-wave, then the chances are pretty slim that you can do anything meaningful on your own, its a very closed protocol with very few reverse engineering efforts going on. Openzwave on google groups is one place to look, but the code they have is not netmf friendly at the moment, and not something to be taken lightly. I am sure you oculd interface the z-wave controller to a Fez via USB Host, but figuring out the next level might take some time…


There are other serial FM wireless solutions for these boards. Depending on your requirements, you may be able to get away with something like the NRFL2401+ . You can get 5 of these for the price of one XBee. Plenty of related information for both herein.


The idea is more to let me FEZ Cobra, NETMF code talk to a service running on my home server, which would have either a ZWave or XBee USB stick in it, and talk to existing devices.

FEZ Slave -> Server Master -> Controls ZWave/XBee devices

But before I go off and buy one of the other, I need to research a little more on which will be the most easiest to develop for, and which has the bigger offer of device (sensors, camera’s, etc…)