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[OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?

USB to serial port adapters exist, they are not expensive.

Flash to store the data in whether flash chips, CF card or other type is perfectly OK, as long as the logger can address the device either directly or by keeping track of which sector it is on.

Your own internal flash chips sodler on the board reduces reliability problems of connectors or wrong type of CF card installed.

Alternative 1 =============

As myself and others said before look at FTDI USBserial adapters, then have the flash inside the device log the data via RS232 at 4800baud.

Then when you need to talk to the PC use the USB to RS232 adapter at very much higher baud rate (115000 or higher should be possible on most micros) Use a simple application on the PC to read the device using a USB pseudo serial port.

This has the advantage of you DON'T have to add USB hardware and software as well as the RS232, and you only need ONE serial port. The flash can be soldered on board a smaller and more portable and SEALABLE weatherproof device.

Also you don't have to get your USB checked on hundreds of USB combinations and buy IDs etc..

Alternative 2 =============

Using a CF card in a PC without a file system and doing raw read/writes has a basic problem. Windows allows raw read/writes when a physical drive exists and has a drive letter. CF card does not have a drive letter until the Plug and Play from detecting the CF enumerates it and does an auto mount including mount a filesystem. Until you either bypass that mounting of file system or only allow format of device options that windows has on automounting of a device, you wont be able to do raw read/write on a drive that may not yet exist to the system. Floppies and other devices can do raw read/write because the drive physically exists and exists as far as system is concerned.

As someone else has said know what the format of the device is and skip the filesystem blocks is one way, but bear in mind as the CF cards get larger they maybe formatted as FAT16 or FAT32 depending on size of the CF card. That in turn will affect your coding.

CF cards and connectors means all sorts of other reliability issues of the connectors, CF card brands supported, mechanical considerations for sealing and durability.

Those are the basic choices, decide what you want from the product as a whole in usability, reliability and other aspects, using the same serial port in playback mode means less openings and connections to deal with.

--
Paul Carpenter          | paul@pcserviceselectronics.co.uk
    PC Services
              GNU H8 & mailing list info
             For those web sites you hate
Reply to
Paul Carpenter
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Easy solution - Buy RS232 to USB converter, log data in HyperTerminal on laptop :)

I've just finished making something similar to what you describe. It has 2 RS232 ports and a CompactFlash card. The RS232 data is timestamped and stored on the card in the FAT16 file system. Therefore it can be read with a USB CompactFlash card reader in Windows.

Do you want to buy this kind of thing or make it yourself? What is the purpose of collecting the data?

Ross

Reply to
Ross Marchant

You forgot two very important details:

  1. Do you only need one of these or do you need hundreds or thousands of these?
  2. Do you want to build one or do you want to buy one?

If you only need one of these and it's OK to buy instead of build, then buy a used iPaq (or other PDA) from eBay. It's small, cheap, has a serial port, it has a USB port and it can store 32 or 64 or 128 MB or even more if you add a memory card. Software to do GPS and/or raw serial data logging is freely available. I use my iPaq for this purpose all the time.

A few other details which other people have already asked but I'll repeat them here again:

  1. Is there a physical size limitation for this device?
  2. Are there any requirements on the user interface?
  3. Are there any power consumption / battery life requirements?

--Tom.

Reply to
Tom

Yes, It does, I know at least a program , an hex file editor, "hex workshop" if I remember well, that is able to open "raw" device , but I am not totally sure about it's capabilites ( if effectively do what they claims ), I tried with a secure digital card and an USB reader and seems to work.

Reply to
mmm

About half-way down the page there's a rs232 to MMC/SD card kit using a pic.

formatting link

Reply to
dmm

Only one.

Buy.

I didn't know of PDA's using USB to connect with a desktop PC. I had only noticed units using RS232 or Bluetooth ( I wish to use neither of those. )

Size isn't tightly restricted. It needs to conveniently travel on dash with accompanying GPS mouse receiver. But availability of PDA with USB opens up possibility of using GPS receiver that plugs into CF slot. This is for a home project that I may not use for long so I would like to stay under a couple of hundred dollars. If the ideas I'm playing with work,I might use it for a couple of years.

Not really. I'm willing to trade inconvenience for low cost.

It needs to be battery operated but will spend most of its operating time plugged into a cigarette lighter or a wall wart.

Some have suggested a laptop as the logger. Too big. Too expensive.

Reply to
Richard Owlett

If either of those options exist then the converters from RS232 or Bluetooth into USB are readily available and quite cheap (Bluetooth/USB) dongle is about £10/$14). Although I am also certain that one of the PDA's allows hook-up to a PC via USB and also features RS232.

--
********************************************************************
Paul E. Bennett ....................
Forth based HIDECS Consultancy .....
Mob: +44 (0)7811-639972
Tel: +44 (0)1235-811095
Going Forth Safely ....EBA. http://www.electric-boat-association.org.uk/********************************************************************
Reply to
Paul E. Bennett

USB connectivity seems to be standard on e.g. the iPAQ range.

And there's always Bluetooth, of course.

Steve

formatting link

Reply to
Steve at fivetrees

*THANK YOU* *EUREKA* *ALLELUIA* Can you tell you have identified what I was grouping towards ;}

I was dreamin of pre-assembled and tested. Although haven't used a soldering iron in quarter century, guess I still remember which end burns fingers. [ PS I'm so old that I won a Blue Ribbon in a Jr. High Science Fair with a 6AL5 full wave rectifier ;]

I'll have to spend some serious time on that site. They have some things there that open up a plethora of possibilities. I say plethora to hint at benign version of "Pandora's box".

Reply to
Richard Owlett

The major problem with Bluetooth/wireless anywhere in system to be air/spectrum pollution and a pending system security headache. OK I'm known to be fanatic on certain issues. I am one of those that surfing

*WITHOUT* Java/JavaScript and/or cookies is only sane way to go :)

BTW your previous references to Triangle Digital Services and reviewing there offerings of development systems encourage me to keep searching for someone who had already done all the hard work.

dmm from "down under" has recommenced "About half-way down the page there's a rs232 to MMC/SD card kit using a pic.

formatting link
"

That whole site has the flavor of what I was looking for. I suspect my final solution will be formed around their modules.

Once again my thanks to comp.arch.embedded for their tolerance and encouragement.

Reply to
Richard Owlett

You're most welcome.

Reply to
dmm

___ I'd use a PIC with AD converters and USART, say a 16F877A. Use the

24FC512 EEPROM for local storage-it holds 64 kbytes or 32 kbytes of 10-bit AD conversions. You can daisy-chain up to 8 of them for 256K readings. When you are ready to process the data, hook up an RS232 connection between the PIC and your computer and transfer the raw AD readings to the computer. Then let the computer do all the number crunching to convert the AD readings to voltages, and create a voltage.txt file on your computer that you can import into a spreadsheet.
Reply to
Charles Jean

I can understand that attitude.

I thought that the majority of the work had been done by Triangle. This link describes what you need to order from them and goes on to describe the software and logging operations (it is almost a one stop shop in that respect - leaving you just the case, the power supply arrangements and the assembly of the programme components from the library with any special code you needed).

formatting link

I can understand that the cost of that set-up may be more than you desire to pay for such a capability and I won't hold that against you (or anyone else). For some jobs I know the basic boards can be too expensive to consider. I can also understand that the Triangle modules may be physically too large for your project.

Looks like a very small and neat module (I am assuming you meant about 1/3 down the page and are referring to the Ulrta Compact SD/MMC board). If you already have a GPS receiver that gives you the position data then this module could act as your logger and data-go between in any one of the forms that have been discussed in this thread.

You are welcome.

--
********************************************************************
Paul E. Bennett ....................
Forth based HIDECS Consultancy .....
Mob: +44 (0)7811-639972
Tel: +44 (0)1235-811095
Going Forth Safely ....EBA. http://www.electric-boat-association.org.uk/********************************************************************
Reply to
Paul E. Bennett

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