Wireless Serial Adapters

Foxxz writes: "I was looking for a wireless solution to link 2 PCs wirelessly at a short distance (less than 300 ft). I thought about wireless NICs but decided they would cost too much and provide more speed than needed. Alternatively, I began searching for wireless serial adapters thinking they may provide a cheaper solution but found surprisingly most were more expensive. Is there a cheaper way to go wireless?"

Comments

Wireless modems?

[crisco]

Years back we looked at some wireless modems of some kind but it was so long ago that I haven't a clue as to what they were. Lotta help, eh?

I don't think you're gonna get much cheaper or easier than 802.11b stuff. You can get USB cards for less than $100 each, 300' is pushing their range but definately possible out of the box. With custom antennas, people get miles outta the things. Bonus advantage, you get the network stack and all the software that works with that.

If you feel like hacking hardware you might be able to come up with other solutions. Do you have line of sight? Then how about modulating a laser diode? Low bandwidth requirements? How about an old modem and a cordless phone?

Chris Cothrun
Curator of Chaos

Yes, but no...

[Bryan Andersen]

Yes you can get it setup for cheep, but only if your willing to do some hardware hacking as well as possibly some software hacking. My sugestion is go with the wireless lan. For a two PC setup I'm told you don't need the access point. That brings the price down to a reasonable level.

Digikey sells the Linx RF modules which cost $200-$250 for the evaluation kits with all the parts you should need. That's about as cheep as you will get. Note you will need some more hardware linke cases and power supplies. The EV kits just provide 9 volt batteries. Works for testing but not for long term use. After you get the physical link working, now you need to get the software working. That means more effort. Oh, as an after thought. If you are doing this for yourself (not a company) you need to get yourself a HAM license to muck about with RF devices. Otherwise if it's for work, go get only FCC approved devices. Dealing with the FCC regs will quickly cost more than the fancyest gear on the market.

Why?

[cr0sh]

What is in between 300 feet that you can't string a simple cable?

If you absolutely have to have wireless, look into radio modems (also known as packet radio). Most of these are relatively inexpensive, small, and easy to use. Most require some kind of backend transmitter/receiver - a cheap hacked CB would work.

Also, look up homebrew lasercomm systems - some of these use actual lasers (here is one such project) - I have seen one (Ronja) that uses high brightness LEDs.

There are many solutions to this problem - but the cheapest (not to mention easiest, and quickest) one is a cable.

Worldcom - Generation Duh!

Build it yourself

[squeegee-me]

If you have the knowhow, Tech-America/Radio Shack have 433 Mhz transmitters and recievers in their catalog. They have about a 200m range, and if I remember from the pinout diagrams, they don't need much more than power and a signal feed. They cost about $20 for a pair, and the two will fit in a film canister. The one is as small as two dimes stacked. I think you could easly grab a pair of DB9 connectors, and a pair of each of these, and throw in a battery or two. End result serial port plugs that work with eachother. Only drawbacks might include power draw on the batteries, getting the two tranceivers and two recievers to run on diffrent frequencies, and finding the limit of data speed through them. You might be able to adjust the RF with a standard police scanner and a test tone, and then adjust the reciever using a speaker and a small amp circut. The units can be found here, and there is no FCC licence requiored. Also they support both analog signals and digital signals, but they us AM instead of FM for the signal type.

WiFi cards are cheap and easy

[Helix150]

Dude all you need is some WiFi (802.11B) gear. Get one card for each computer and run in ad-hoc (no base station) mode.

First get two WiFi PC cards. Yes I know you dont have laptops. Add two PCI-PC card adapters and you're set. Total cost $140 per computer, and you get 11MBPS. Also includes encryption if you feel paranoid.

This is industry standard gear, so if you ever decide to upgrade to a 'full' wireless lan you can get a base station and add as many computers as you want.

Old Ricochet Modems!

[Kalrand]

The simplest wireless-serial connection that you are going to get is if you use a pair of old richochet modems in their direct transfer mode.

This might require you to hack a bit of software, but it is a true wireless serial link.

Here's a link on how the whole thing works.

Ricochet Modem FAQ

Kalrand
-The Voice of Reason