Looking for a control box

Why?

You have a cost target per station? How about 8 Olimex MT128s (about $50 olimex.com) plugged into an 8 channel rs232 card?

Without giving out too much information, I basically want to be able to control a set of parameters in a program on a PC remotely from a simple (hopefully cheap) box. Dial A will scroll through a list of options and then Dial B will change a value associated with the option chosen with Dial A.

If the box can send information to the computer giving it an ID of which box is currently sending the signal (could be IP based, dip switch setting, whatever), along with which dial is being turned, and which direction, and the computer can update the LCD accordingly then I should be able to write some software to do what I need.

I think that building a box like this is probably not too terribly difficult for someone with some know-how... unfortunately I don't have the know-how to do it on my own. I have seen some development boards that I think could possibly be used to do something like this, but as I said... I don't really have a clue when it comes to this stuff.

One of the boards I was looking at is from Rabbit Semiconductor:

That board has ethernet capabilities built into it and probably more power than I would need. If there is something simpler that would do the trick that would be great.

Are there any good resources anyone can recommend that I look at, or other products I should be taking a look at that might get the job done?

Thanks again for any help you can provide.

Brad

Who's gonna write the software on the PC that monitors the source, the changes of knob positions, records the new data, and updates the displays?

Who's gonna define the protocol for the ethernet packets back and forth? How do you avoid collisions or loss of data? Redundancy, error checking?

The boxes are a part of your task, but they'll never get built until you specify the whole system in detail.

Or clearly specify the goal and let let engineering types propose how to implement it.

With your more specific vague description maybe others might see an obvious easier off-the-shelf way to start.

Far easier to do it via ( RS232) RS485- 4000 ft range....... Software overhead would be way too high with Ethernet.

Assuming he's going to have a protocol layer such as TCP/IP, I'd suggest it's no harder -- maybe even a little easier -- to use Ethernet than "raw" RS-232... especially if he's using a "very high" level language such as Python, etc.

I still don't see why this isn't just a VB program.

I'm assuming and hoping that if I used a board like this:

that it will have the tcp/ip stack built in. The board is probably overkill for what I need, but if the boards cost a little more but can get me up and running faster and save a lot of software development time then it will be worth it.

To answer the question of who will be writing the software, it will probably be me. I am a programmer. I have never done this type of thing before, but assuming I don't have to write a TCP/IP stack from scratch I think I should be able to handle it.

The biggest problem for me is knowing what hardware I need to buy so that I know I'll have a box that I can communicate with and get the job done. The next piece will be buying the components and getting someone to put them together for me. The programming is the least of my worries (I think... maybe that will turn out to be a lot uglier than I'm thinking but I hope not).

I think I should be able to attach an LCD display, and some digital pots to that board and do what I need, but I'm mostly just guessing. I'm hoping that there is something out there that is already built so I don't have to build my own. Or at the very least that someone out there may have some experience doing something remotely similar and can give me a bit of advice.

Thanks for everyone's input so far. I know it's kind of difficult to answer someone's questions when they don't have a clue what they're talking about and they're a little vague in their description of the problem. I can't give away all of the details on exactly what I'm trying to do because a friend and I are hoping to be able to build a product that will be worth buying when all is said and done. For now we just want to get a working prototype going, we can worry about finding simpler boards and getting things a little tidier after the prototype is done. We just don't want to spend a bunch of money on stage one doing things wrong.

Thanks again,

Brad

yes, look at "RABBIT" based embedded processor boards. they come in a variety of packages, many of them have ethernet connections, along with serial connections with many IO lines. you can get stand alone Serial LCD 40x2 Row,Col displays that can be driven via this little RABBIT board.

you would need the Dev package to write the code on the PC, it comes with examples on how to use the analog, io, serial, network functions.. etc.. we use them a lot at work, make's for more compact usages over PLC's. most of them can fit in the parm of your hand!

The software will probably (hopefully) end up being quite simple. Possibly VB, Python, C#, whatever. The hard part for me is getting a box that can remotely send the parameters to the PC with the software on it, and having the PC update the LCD display on the box. I don't want to have the possible display values hardcoded directly into the box itself because I want to be able to change the possible options via the software.

I basically want a very generic box that can be monitored with the software and can display whatever I want it to display (within the limitations of the LCD display that we use) based on which knob has been turned and in which direction.

In the end I think a box like this could have a lot of different uses, but we have one specific use in mind for now.

Thanks,

Brad

You still aren't dealing with the hardware side. If you are skilled enough, you could possibly do it via USB.

I think I'm having a hard time getting across what I'm trying to say.... or else I'm not quite understanding what you're saying.

I will have to write software at some point, but what I am trying to figure out right now is what type of hardware I can use to connect to the PC. Either a pre-built box that I can buy from somewhere, or something I will have to get custom made.

I need to have probably 6 - 8 boxes that have 2 dials and an LCD on them. These boxes need to be able to communicate with a PC using software that I will write.... later, after I know what kind of hardware boxes I am going to use.

The language, protocol, etc. will all be dependant on which box I am able to get that will do what I need. If someone can point me to an ethernet box I'll write the software accordingly... if it uses USB, serial, infrared... whatever.

Brad

IIRC, PIC (MicroChip.com) have processors which can do IP, LCDs and USB. You may need one for each but they can talk to each other.

If the PC has a parellel port, it's quite easy to interface to it.

You want a box with two knobs and an LCD, that communicates with the PC, right? You could do this in a 3.5" x 5" x 1.25" project box.

I wouldn't use "knobs", though, unless you can get something like quadrature encoders - mouse sensors come to mind. UP/DOWN tact buttons could do the job, but admittedly, there are some apps where a knob is better. :-)

Then find a micro and LCD, drive the LCD with the micro, have it listen to the two knobs, and talk through a bidirectional LPT port.

I've never heard of anything like that right off-the-shelf, although there are developemt boards or experimenter boards or whatever that have a micro, an LCD, and a monitor program. That could give you a starting place for proof-of-concept.

Good Luck! Rich