Question on Remote Data Access

PC Anywhere used to offer telephone access as one of the options for remote controlling a PC. You might want to give that a browse.

te controlling a PC. You might want to give that a browse.

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I don't have a PC at the cabin. I just have a small controller board that puts the temperature data into flash memory. I can download the data into my laptop over RS232 when I am local. I am just trying to see if there is an easy way to get access to this file over a phone line.

"biff" wrote in news:1167769912.559337.126550@

I just saw this PC:

Spam Catcher wrote in news:Xns98ACADBAA716Cusenethoneypotrogers@127.0.0.1:

Perle carries several serial to terminal/ethernet devices. Something like this may work:

A couple other companies sell similar devices - at a much lower price... but I'm not sure if they're any good.

So, a MicroPC (or old PC) might turn out to be the cheapest solution to do what you want?

I hadn't seen the MicroPC before and I like that idea. I had tried using a PC before, but the power at my cabin is very unreliable and I was having trouble keeping the PC running. Thus, I started looking for a more reliable solution. My little microcontroller on a 12 V UPS runs like a champ (never misses a beat).

I would like to bounce an option off of you. I could hook a modem up to the RS232 port on my microcontroller. I can write a short program to command the modem to answer the phone. I then should be able to use hyperterminal or kermit from my PC to read the file. What do you think of that? I don't have any security concerns. The only information someone could get is my lake level and lake temperature.

Hook up a modem to the board, set p the modem to auto answer and have the program wait for some string (hello world :-) and dump the data. When done wait for another string to delete the data then a command to hand up. If no hello then hang up (+++ ATH0).

I've simplified this a bit for explanation but it should be too hard to do with the correct modem. You'll need an external modem, a phone line, an RS232 cable and your stamp. I don't think you afraid to program. :-) To use just dial in when ever you want issue the hello and log the text data to a file. You could write an automated program on your local PC to dial out and retrieve the data. I have other ideas too.

Or just configure the modem to always answer the phone. Most will let you set this into the flash NVRAM. Then you'd just be calling it and getting connected straight to the serial device. If you wanted to get fancier, and the phone line had Caller ID, you could have your serial device look to see what number is calling before answering.

But if the serial device is programmable enough, what about having it call you instead? You could then have a PC on your end do the same thing, see what number is calling (perhaps even by time of day) and answer only when it knows the cabin's calling. That and the receiving PC could do all the hard work that the programming limitations in the serial box might not support. Call the PC and let the PC do all the rest.

-Bill Kearney

I like it!! Both the caller ID and the "phone home" feature would be great and don't sound tough to implement at all.

I want to thank everyone for the excellent suggestions. This has been a very useful discussion for me. I am now off to set this up and try it out.

Biff,

It would appear that a small PC such as the "MicroClient Jr." from

Alternativly you could just write a small "C" program to transfer the data from the unit as required and dial you back at appropriate times automatically. Saves you dialling in and doing anything.

Sid

biff wrote:

"biff" wrote in news:1167782471.294762.30330 @s34g2000cwa.googlegroups.com:

How about adding a cheap UPS. A 900W UPS runs for ~80.00 and can power an old PC for >1 hour. If you hook up an old laptop, it can run for hours without power.

Does your microcontroller store data onboard?

I believe a decent external modem can be set to auto-answer with the proper AT command. Perhaps give that a try? Just hook up a modem directly to the RS-232 interface?

I have a small UPS hooked up to my little controller board right now. I am going to try the modem route for now, though I will probably put one of those MicroPCs into another application that is not quite as environmentally nasty (down by the lake, etc). I had never seen those before and they look great.

Yup

I am in the middle of doing that right now.

I think you need a Intel P5 with 1 GB of RAM and a licenced copy of Windows. Also you need a 200mb installation of the MS .NET framework. In addition to this you also need to write a custom program using MS Visual Studio that relies upon the 200 MB .NET framework.

Gorge

biff wrote:

I think you forgot the smiley!