Post by thread:[OT] Tech America RF modules

All, Browsing through the latest Tech America (now Radioshack.com) catalog, I came across the following RF Transmit/Receive modules. As the question of where to buy RF modules appears frequently on the list I thought I would pass along this info FWIW. Cat #: 900-6896 Mfr's #: TX433 UHF Transmitter 433.92MHz $9.85 3-12v operating voltage range, 200 meter range. Cat #: 900-6895 Mfr's #: RX433 UHF Receiver 433.92MHz $9.95 4-5.5v operating voltage range. If anyone has used these modules, please provide us some feedback. These look perfect for a semi-autonomous (a la Mars Sojourner) robot I have been thinking about building (PIC based, of course). Adam Bryant (age 0x23) spam_OUTabryantTakeThisOuTpeaktech.com (work) .....adamdbKILLspam@spam@juno.com (home) Parker, CO, USA Robotics, RC Airplanes, anything using a PIC ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: dl.http://www.juno.com/dynoget/tagj.

I bought a pair. They work. I fed a 1Khz square wave into the transmitter and scoped the receiver output. I have not actually used them yet for data, but I imagine that a set of Holtek remote control decoder chips would work well, or you can roll your own serial protocol. One thing I would recommend, if you roll your own protocol, is to make sure that on and off time are balanced. An NRZI type algorithmic perhaps... (Please don't ask *me* about NRZI, I only mention it because I know of it as one of the balanced code schemes out there.) The receiver as a very active gain control and you don't want it jumping all over trying to track the average energy of your carrier as it bounces all over. If and when I get to it, I'll share my success / failure with the list, but it will be a while. Too many other tasks and too little time. Dan On Tue, 5 Oct 1999 10:30:16 -0500, Adam Bryant wrote: {Quote hidden}>All, >Browsing through the latest Tech America (now Radioshack.com) catalog, I >came across the following RF Transmit/Receive modules. As the question >of where to buy RF modules appears frequently on the list I thought I >would pass along this info FWIW. > >Cat #: 900-6896 Mfr's #: TX433 UHF Transmitter 433.92MHz $9.85 3-12v >operating voltage range, 200 meter range. >Cat #: 900-6895 Mfr's #: RX433 UHF Receiver 433.92MHz $9.95 4-5.5v >operating voltage range. > >If anyone has used these modules, please provide us some feedback. These >look perfect for a semi-autonomous (a la Mars Sojourner) robot I have >been thinking about building (PIC based, of course). > >Adam Bryant (age 0x23) >abryantKILLspampeaktech.com (work) >.....adamdbKILLspam.....juno.com (home) >Parker, CO, USA >Robotics, RC Airplanes, anything using a PIC > >___________________________________________________________________ >Get the Internet just the way you want it. >Free software, free e-mail, and free Internet access for a month! >Try Juno Web: dl.http://www.juno.com/dynoget/tagj. >

Adam . . . . I guess it depends on what use the * RF * communications will be put to. Radio Shack has offered a large selection of * Remote Control * cars ,etc. and usually these are going to use some limited encoding , like is offered by * Holtek * parts. Moving up to producing a data link , may require a design using * RF * componants ( i.e. RFM Xceivers ) that have a faster rise / fall time of the modulation. I was faced with this recently and had a design that used a very narrow detection window. The majority of the parts that I came across ( for xmitting ) would operate with rise /fall times at about 100 to 150 usec. max. So , even though this timing might work for a 1 kbps , OOK transmission , if the receiver is looking for fast transistions . . . . . oops! The RFM 3001 ,3002 , 3003 are xmitting with rise /fall times that average 6 to 12 usec. and provide for up to 119 kbps. Steve {Original Message removed}