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Wireless (Bluetooth) RS232?

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    Wireless (Bluetooth) RS232?

    Has anybody had any experience with RS232 to Bluetooth adapters to wirelessly connect an RFID reader to the Homeseer PC? Where I'd like to position a reader and where my HS unit sits makes me feel faint at the prospect of trying to string Cat 5 cable. I know the range of Bluetooth isn't spectacular but I'd be willing to give this a try if I heard some positive feedback. I'm interested in anybody's experience with these wireless adapters, be it for hooking up a printer or any other use. I plan on using it for the RFID reader so I'm really just looking to verify the efficacy of the product. If you have used it with RFID, all the better.

    The adapters are like the ones at this Amazon link. (although I'm not stuck on these particular adapters, just wanted an example to show you so you know what I'm talking about.)

    For clarification, I'm thinking about an active iAutomate RFID reader.

    Also to add one more level of complication, my HS unit has USB inputs only so the wireless adapter at the HS unit would have to be plugged into a serial to USB cable.


    I don't have any direct experience but I don't think they are designed for back to back connection. The adaptor connects to your serial device and then on your HS PC you have a Bluetooth dongle, then you connect through the Serial Port Profile (SPP) to this device. When I played with it, although it was some years ago I had to go into Bluetooth properties on the BT control panel and connect to the device manually. This was my only concern that in the event of me needing to reconnect (signal loss etc) I would have to do manual work - I don't know whether or not this has changed.

    I am very interested in this (not for RFID) as I have an application for it, I'll probably build mine with one of these though and with a MAX232 or similar level converter.


      My hat's off to you for having the initiative to build one. A long time ago in college I dabbled in building my own circuits for a short while. I'm looking for a more convenient solution right now. That little >3cm long card looks like a lot of fun to experiment with though. If I only had more time in life . . .

      Actually, the example I gave with the Amazon link wasn't the best. I was just trying to get the idea across. I don't have a lot of faith in the small nub like bluetooth dongles that you plug into your USB port. I've got one for a laptop for a different Wifi router I set up and it works marginally well at best. Not the greatest signal strength or speed. I've since come across what may be a more interesting solution.

      At approx $100 for two of them, it *seems* like it might be a workable solution. I'm still hunting for reviews. Also, this site recommends a serial to USB cable if your receiving computer has no serial port. This is good to hear. I'd need at around 200' of Cat 5 cable plus the tools to crimp ends onto the cable, the ends themselves, plus the aggravation of getting it pulled from point A to B . . . $100 bucks for the two wireless units doesn't seem too bad. I'm sure every little piece of technology that is used to interface between the RFID receiver and my HS unit will only slow down data transmission speeds, so I'm interested in what kind of speed the iAutomate unit works at. This wireless system boasts a max baud rate of 115200 bps . . . I think that would be adequate for my uses . . . It's not like the RFID receiver is sending high resolution HTML data or video . . . just some log file data to report movement/position, right?

      It boasts a range of 1600 feet, which I'm sure, like all such RF distance specs means in a clear, line of site environment. If that's accurate it should get from one end of my house to the other pretty well.



        I will throw this here in case anyone is interested, on eBay you can get those cards linked above in a little bit of a more friendly package (LED/0.1" headers).

        I had a USB barcode reader in the kitchen I have been playing with for a while (which runs a shopping list script and downloads UPC data) but no reliable way of getting the data back to my HS PC (did not have the heart to run a long serial cable and have no wired network where it is). I did have the reader connected to my Joggler running XP but I switched back to Linux and the only way to differentiate input devices in XP is to use some low level system hooks - I had no idea how to do this in Linux but running the same app I wrote in mono on Ubuntu did not go down well (did not expect it to really). Efforts to work out the pinout of the USB reader to try and get RS232 also led to a blank.

        Ended up getting a 2nd hand Symbol reader in decent condition but this time with a serial output, figured that will be easier to get talking wirelessly. Ideal for use with the bluetooth board I had in mind to play around with. Quick circuit put together with an ST232 to change the negative levels coming out of the device and I have have a quasi wireless barcode reader. I still have the cable coming out of the reader and the box is hidden so not truly wireless, but there is no cable going back to the HS PC.

        Setting up the PC side of things was less trouble than I was expecting, once the device was powered up and paired then it appears as two seperate COM ports in device manager. One port is incoming and one is outgoing, not entirely sure why but as I am only using incoming data I only opened the incoming port.

        All the stuff that HS sees is no different to if it was a wired port, I am just trying 9600 baud at the moment but apparently it can do faster.

        Range is a fair bit shorter than I was expecting, not sure why this is - either interference from my wifi/dect phones, construction of the house (one thick brick wall between the board and my BT dongle), lack of antenna or a combination of all of those. I probably only have around six metres range at the moment but I am going to try and extend that.

        Heres hoping it is relatively stable in practice and I don't suffer any dropped connections, not sure how I will handle that. I don't know if opening the COM port will automatically do the rest for me.

        Highlights of the circuit build is my complete laziness to fix the main circuit down with anything other than hot melt glue, drilling the hole for the LED too big so needed yet more glue. On the upside I cut the d-sub cutout the correct size first time, a small miracle in itself.
        Last edited by mrhappy; August 17, 2012, 10:00 AM.