Wireless RS-232 for Palm and Other Devices? 17
The Serial Anonymous Coward asks: "I have all these old RS-232 interfaced items (my palm pilot, trg pro, etc.) and i really like them for what they do, but can't understand why there aren't any dirt cheap limited range wireless serial ports for them? Just want a small dongle to hook into my desktop, and the same for my palm pilot--so in my house, within a small distance (50 feet, maybe more if possible) I can use this to browse the web, check my e-mail, whatever. I mean I don't need much faster than 56k, and less probably wouldn't be bad (how fast can a palm process the data anyway). I know the laplink people had a product like this years ago--didn't last long, I'd love to get a hold of something similar....anyone working on it for a hobby? I don't need bluetooth (but a serial -> bluetooth adapter would be fine)"
Re:Umm.. (Score:1)
Re:Umm.. (Score:1)
The circuit I mentioned shows both an IR diode and a photodetector, therefore it -is- also two-way.
For communicating between two devices in the same room this might be perfectly adequate, and it's likely to be much cheaper than a radio link. Also since IR doesn't go through walls and is greatly attenuated by ordinary glass, it's inherently less of security risk than a radio link.
Hacking handhelds (Score:2)
http://www.google.com/search?q=wireless+rs232 gets about 24,000 hits, but most of the commercial solutions are oriented towards scientific data-logging applications and other deep pocket uses. One source is Parallax, makers of the Basic Stamp. They have something that might work here [parallaxinc.com] -- look at the RF products section. Personally, I would homebrew it with a bare PIC microcontroller, but the 'Stamps are a lot easier for the hobbyist to deal with.
Someone mod this guy up... (Score:2)
Heh, if you can make them quickly and easily enough, there might be a small business opportunity there (maybe via a Nuts and Volts ad - check out all of the small business robotic kit companies that exist!)...
Where are *YOU* looking? (Score:5, Informative)
At the bottom of page 85 is a 1/3 page ad for Abacom Technologies. They sell ISM (418 and 433 MHz) band Rx and Tx modules that could be pressed into service for what you want. One drawback-- half duplex only. But it's a complete 38,400 bps transiever for $140.
On page 47 Radiotronix has an ad, but their stuff is limited to 4800 bps.
On page 32 there's a feature article about a wireless (RF) irrigation control system. It's not exactly what you want, but it will tell you some of the things to think about.
(Gets out MX-Com catalog)
Their CMX017 transmitter and CMX018 receiver can be used to build such a device. For your speeds they'll do fine (I wanted 10 Mbps; they won't go that fast!).
(Looks at Xilor pamphlet)
Nope; their stuff looks like remote controls (keyles entry stuff) only.
(Gets out Maxim selector guide)
Hmm. These guys have a range of 1800 MHz PCS and 800-1000 MHz tunable tranceivers. These could work.
No, none of these are "turnkey" solutions and they all have their drawbacks. It's not true that stuff isn't out there. The Abacom Tech stuff is very, very close.
You just have to realize that this is a very small market; just because we have PDAs (I just got a Visor Prism for Christmas!) doesn't mean there's enough PDA owners to support such a device.
I might like one, but right now my latest hardware project will be making a battery charger for the Prism that doesn't cost the $50 they want for a cradle. My computer isn't on the way out of the door in the morning; it'd be nice to have a non-HotSync-able cradle by the door just for charging.
Building one now . . . (Score:3, Informative)
http://laipac.com/products/wireless.htm
(I'm using the RLP916A and the TLP916A on that page).
I haven't gotten the radios in yet. I have the other parts though. A transmitter/receiver pair ends up costing $20 including the shipping, the PIC and the MAX232 make up about another $6 if I remember correctly.
If anyone is interested in these, email me in a couple of weeks and see if I got it working.
If money is no object... (Score:5, Informative)
Then again, whats wrong with the cable?
Re:If money is no object... (Score:1)
thanks! bye!
HandiLAN (Score:1)
http://www.handisystems.com/handilan.htm
Unfortunately their price list (dated Jan 1st 2001), lists the product as N/A so you may need to dro pthem a line to see if it is still being manufactured.
Most barcoding equipment is RS-232... (Score:1)
- Freed
Didn't look very hard.. (Score:2)
You could probably make something that'd be able to encode a 1200-2400 bps signal pretty easily. 9600 or higher is trickier. There are 99 44/100 ready solutions from Linx Technologies (www.linxtechnologies.com) and others make little modules that do exactly what you want.
For a 100% turnkey solution, last time I checked, Parallax (www.parallaxinc.com) sold a data in here - data out there set of modules that talked at 9600 baud up to 1/4 mile LOS.
RFnet (Score:1)
Any person involved with a FIRST team from 1990-1998 will have fond memories of this thing. Now we use a similar product (RS-422 though) from ewave.
They have really good range, and work very well. They are also powered from the RS-232 port, so no external AC adapter.
Check ebay.