At 09:10 AM 2/12/98 +0000, you wrote: I have looked at the recent postings on RF modules. I have offered some of the Pan Atlantic radios to some users but am awaiting on stocks. Like a number of PIC people I am not an RF engineer. I require a transceiver which has the following: 1. It should be approved for the country in which I am going to operate. It is ok for a hobbly to play around with radio but if producing something for sale it must be approved or the FCC or similar will have something to say!! The INDIGO radio has been tested and approved by the FCC. 2. It should require a minimum of parts to make it work. The INDIGO radio only requires a 5 volt supply to start operating. The antenna is supplied with the radio. You can run a PIC directly into it going up to 4800 baud. (newer models will be able to do some 30Kbaud.) To connect directly into a PC just add a serial chip- Max203/232, etc. 3. It should not require any special RF knowledge to operate the device. There are different modes built into the PIC16F84 which controls the radio. It can be put in various repeater modes, PING-PONG mode for range checking, a straight-through mode for PWM, etc; a send with error check; a send with no error check. Thus the radio can be easily set up to check range and then set up again in the operating mode with a minimum of effort. 4. It should be small, compact and light. The indigo is about the size of a postage stamp and very light. 5. The range should be sufficient for most tasks. The range of the INDIGO radio is about 150-200 metres but this is expected to increase with the new modules. There are a number of radios I have used but usually they fail one of the above criteria. I have purchased some from RF Solutions but have not used them yet. However, I doubt if I would use them in a commercial product. This is because I do not have the equipment to test them and ensure they conform to the regulations. I also do not want to pay to have them tested and I am in no way qualified to perform these tests. The INDIGO radios operate at 915MHz which is suitable for both the USA, Australia and, I believe a number of other countries. I have used teh RADIOMETRIX radios and find them very good but it is very intensive on the use of port pins (9 needed) whereas the INDIGO can just use RF232 in and OUT. My apologies for going on too much. If anyone would like additional details email me privately. Peter Grey Australia >At 13:06 01/12/98 -0500, you wrote: >>It seems like there are a lot of companies selling RF modules now that >only require data, power >>and an antenna. I'm curious to hear about anybody's experience with >these modules, especially >>in light of someone having no RF experience. > >I think I qualify for that... > >I got a 418MHz Tx/Rx pair from RF Solutions in the UK, total cost about >10ukp (about 16usd). It really is remarkably simple to use- they have 2 >transmitters- one has 2 pins (and is about the size of a small tantalum >capacitor), but it needs an external tuning capacitor. The other is >slightly larger than a 14-pin DIL package, but needs no external >components, and goes up to 2kHz switching rate. That's the one I got. The >receiver has more pins, but only because ground and power pins are >duplicated- it's a SIL module. > >I had about 1/2 hour's trouble to get good grounds with the receiver (on >blue plug-board), during which I was getting a lot of spurious outputs, but >after that it does "exactly what it says on the tin", as a UK advert says... > >> How hard is it to integrate an antenna onto one of >>these things? > >I found that for my application, removing the receive antenna still gave >acceptable signal levels over a short range and significantly reduced false >spikes... but I just used a short piece of wire (about 9cm, as per the data >sheet) > >> I assume I will have to build a protocol to deal with the unreliability >of RF >>comm, but how unreliable are they? I am trying to build a wireless network >of sensors, and would >>like to use these for communication. Any advice appreciated. > >I've used the 16c7x series USART to cope with noise etc, but my application >is not critical... you could always use parity or a stronger >error-correction code and still use the USART. > >RF Solutions website (I posted the wrong address a couple of weeks ago) is at >http://www.rfsolutions.co.uk/ > >Nigel >-- >Nigel Orr Research Associate O ______ > Underwater Acoustics Group, o / o \_/( >Dept of Electrical and Electronic Engineering (_ < _ ( > University of Newcastle Upon Tyne \______/ \( > >