Cheap "Touch PC" control panel? Or - How to Hack a GPS?

I want to create a "control panel" to control some electrical devices, specifically two 240V electric pumps and 1 motorized valve. There will also be two temperature sensors.

Initially I was thinking of doing this with a Netduino and an LCD panel, plus assorted electronic components (relays, power supply, etc). However I then started looking around for LCD touch panels, but these are pretty expensive and I'd still need the Netduino.

Next I started looking for "Panel PCs" running Windows CE. You can find those but they are also a bit pricy and a bit large for my needs. I don't need more than about a 6 inch display.

Then I realized that there are tons of cheap GPS systems with touch screens running Windows CE, some with HD screens, for as little as $40 to $70 on eBay. That is cheaper than the monochrome touch LCD panels alone I was looking at earlier! It will feel weird converting a GPS to a simple control panel, but for that price how can you go wrong given that I don't need to worry about the assorted electronic components, case, power supply (a simple USB power supply will do) etc?

Now my questions are:

1. How do I unlock such a device and develop a Windows CE application for it?
2. I'd need to get to the USB port so that I can somehow control the electrical devices, and also read the temperature sensors. Am I correct in thinking that once I can get to the Windows CE desktop that the USB port will look like any other USB port in Windows?
3. My understanding is that I'll need to use Visual Studio 2008 to develop the app, since VS 2010 no longer supports Windows CE? This seems to have some interesting info regarding that.

One would think that if you can get a GPS that runs Windows CE and has an HD touch screen for less than $100, why can't one get just a simple Windows CE touch screen PC (sans GPS hardware) that is designed to run applications, or create embedded solutions with?

Any help appreciated...

Hmm, this one says:

Windows CE 6.0 - You can install games and other software that is compatible to [sic] windows CE 6.0

So I guess these are already unlocked. I mean, why else would they mention Windows CE as a bullet point?

Wonder if one were to fire up VS 2008, would it see the device as something you can deploy a Windows CE app to? Sounds like it... And would the USB port be available? Probably.... And what about touch input? Not so sure about that one. There has to be a way to listen for touch events, I'm sure.

Using a GPS for this purpose is getting more and more attractive. That combined with this will get me very close. Those relays won't be able to drive the 240V pumps but they can drive larger relays that can then handle the voltage/current.

@BitFlipper: FYI, 19-inch touch screen kit cost $65.99  to $189.00(wide) on e-Bay only.

Easier just find some second hand notebook with USB port and plug these in.

@cheong: Well I'm trying to make a compact "control panel" similar to what you see here. That unit is typical of what size I need and it is rougly 6" x 8 "in size and about 2" thick. It needs to be mounted inside an electrical box. It will be tough to do that with any kind of notebook/netbook, and on top of that the notebook/netbook won't have a touch screen. Also keep in mind I would need to mount the IO controller in there as well, including the two additional larger relays to drive the two motors.

I'm seeing a re-purposed GPS as having the following advantages:

• Extremely compact considering the hardware it contains.
• No need to assemble anything. Building anything from scratch is going to take a long time, bulky, kludgy, expensive and cheap-looking. 
• Already has a high-def, bright display (a requirement for a car GPS).
• Has a built-in backup battery. Something that would have added quite a bit to the cost if building something from scratch.
• The cheap GPSes you find on eBay are cheaper than any combination of hardware I can put together with similar functionality (if that is even possible, which I doubt).

The only downside I can think of is the reliability of the unit. These GPS units are cheap and I'm not sure how they would hold up when installed inside a metal box that sits in the sun all day. Will the battery explode after 3 months? You'd think they will be somewhat hardened considering they need to sit on dashboards inside cars that also sit in the sun all day.

Could there be other downsides? I guess ordering one of these and just trying it out can't hurt.

Now that you mention it, it looks like a cheap and quick way to get some level of automation around the house... maybe the only thing missing is a WiFi adapter...

@PaoloM: Yea I'm amazed at the harware you can get for $80. I just bought this one on eBay (free shipping from China). Sounds a bit dodgy ("The cellphone (?) comes without original box for security,that's in order to avoid inport tax for you"), but the seller has good reviews so I guess it will be OK.

That one even comes with a 4GB card and Bluetooth. Maybe I can make some sort of system that when I bring my WP close to it it will download the latest stats to the phone. And with that 800 x 480 screen I would be able to go crazy with all sorts of running graphs for temps etc. Just hope I can get access to the USB port, but I'm sure I would be able to.

All of these seem to give you access to the Windows CE desktop, most of these even show pictures of the desktop and that particular one talks about Word, Excel, PDF, PowerPoint etc so I don't foresee any issues with the unit being locked.

Hmm... memories of the early .NET compact framework...

System architecture of a .NET CF app

Screenshot from the above

LOL. I still think though that it is better than the .Net Micro Framework you get on Netduinos. Much faster. I remember doing realtime DSP on my iPaq (track your vocal pitch in realtime with a running graph), whereas there's no chance I'll ever be able to even do the most simple of DSP operations on a stream of audio data on a Netduino. The Netduino runs C# code roughly 100 to 1000 times slower than the equivalent C++ code. So on the GPS the code would run about 10,000 times faster than on the Netduino since the GPS's CPU looks like it is running at least 10 times faster.

However for my current requirements a Netduino would be more than fast enough if it uses a simple display. But just imagine all those fancy graphs I can do on the re-purposed GPS!

Apparently WinCE 6.0 already has a USB CDC driver (where WinCE 5.0 doesn't), which is apparently what I need to communicate with the USB IO controller. Well that answers that question I guess. I almost bought a WinCE 5.0 GPS, good thing I didn't.

Not sure what else would be an issue with going down the hacked GPS route...

Just do it!

Oh, and report how it works, so everyone can benefit from your foolishness...

@PaoloM: Yea I will, but it is going to be a while. The GPS ships from China and I won't get it for 2 to 3 weeks. But I will post an update.

Looks like I'm stuck using VS 2005 for this. WinCE 6.0 isn't supported by VS 2008 or later.

2 hours ago, BitFlipper wrote

Looks like I'm stuck using VS 2005 for this. WinCE 6.0 isn't supported by VS 2008 or later.

Heh. I remember how slow 2008 looked compared to 2005. And how slow 2010 looked compared to 2008. I think 2005 is simply going to fly off your machine

Is there a reason a Netduino Go module like this one wouldn't work for you. http://nwazet.com/touch-display-module

@EndymionMKII:

Yes that is interesting, and I was not aware of that one. However you have to realize that for $10 more I'm getting a completely built unit, including compact case, backup battery, much higher res display, a built-in USB port, Bluetooth, a much faster CPU and the compact framework as opposed to the micro framework. For instance I can use WinForms, and there should be built-in support for touch when using WinForms controls whereas I'm unsure how that works on the Netduino GO.

If I knew about the GO before starting to look for alternatives, I might have gone with that instead. However after realizing what the GPS offers, it will be hard to justify going the Netduino GO route.

Of course there could still be some reason why the GPS won't work out (for instance if I can't get the USB port to talk to the IO board, etc). Time will tell.

Quick update. I got the GPS today, which is record time based on the expected delivery time so I'm quite pleased with that (they said 15 to 30 working days, it's barely been 7 working days).

I'm also quite impressed with the GPS given the $80 price. Not so much the GPS software, I didn't even bother to fire that up. But the full-screen menu had an option to switch to the CE desktop and it's pretty much Windows CE with control panel, Explorer, Word + Excel + PowerPoint Viewers, even IE.

I was able to switch the USB port from Mass Storage to ActiveSync mode, and my desktop PC sees it and opened the "Windows Mobile Device Center" window where I can sync files etc.

I need to leave soon so I will only be able to do more testing tomorrow but it looks very promising so far. Tomorrow I'll try to connect to it with VS and see if I can compile/debug an application on it.

That sounds way better than I had expected. Keep us posted, this sounds good.

About 6 - 7 years ago, my brother bought me one of those handheld golf course GPS devices. It was essentially a Windows Pocket PC with the golf GPS software pre-installed. There was no "locking" of the device at all. In fact, I even purchased GPS navigation software for it separately, and used it for navigation instead of using it for golf. I actually used it more as a music player using the built-in Windows Media player. Admittedly, it was a little dangerous to using while driving since the UI was designed for stylus and not fat fingers.