Post by thread:[EE] Use of Zigbee modules for one way link?

I need a one way RF link. I'm considering use of 915MHz, but I can not find any transmitters with FCC modular transmitter certifications (http://louise.hallikainen.org/FCC/FccRules/2010/15/212/ ). Section 3.1 of ww1.microchip.com/downloads/en/DeviceDoc/70329b.pdf states that the MRF24J40MA has certification as a modular transmitter. I COULD go Zigbee all the way, except that the "receivers" would generally need to transmit back to the "transmitter" where the data originates. Section 3.1.1 of the datasheet requires the antenna be 20cm or more away from people. This disallows a handheld or portable "receiver." So, what about the possibility of operating one MRF24J40MA as a transmitter and multiple MRF24J40MA modules as receivers where the receivers NEVER transmit? Has anyone tried anything like this? Is it a good or bad idea? THANKS! Harold -- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available! -- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available!

-------------------------------------------------- From: "Harold Hallikainen" <spam_OUTharoldTakeThisOuThallikainen.org> Sent: Thursday, July 08, 2010 9:42 PM To: "Pic List" <.....piclistKILLspam@spam@mit.edu> Subject: [EE] Use of Zigbee modules for one way link? {Quote hidden}> > I need a one way RF link. I'm considering use of 915MHz, but I can not > find any transmitters with FCC modular transmitter certifications > (http://louise.hallikainen.org/FCC/FccRules/2010/15/212/ ). > > Section 3.1 of ww1.microchip.com/downloads/en/DeviceDoc/70329b.pdf > states that the MRF24J40MA has certification as a modular transmitter. > > I COULD go Zigbee all the way, except that the "receivers" would generally > need to transmit back to the "transmitter" where the data originates. > Section 3.1.1 of the datasheet requires the antenna be 20cm or more away > from people. This disallows a handheld or portable "receiver." > > So, what about the possibility of operating one MRF24J40MA as a > transmitter and multiple MRF24J40MA modules as receivers where the > receivers NEVER transmit? Has anyone tried anything like this? Is it a > good or bad idea? Is this any good? It's one of the modules I ordered for the Radio Lights I mentioned a while back. Cheap, says it's FCC compliant and can be run at 915MHz. What data rate do you need? http://docs-europe.origin.electrocomponents.com/webdocs/0d71/0900766b80d715d0.pdf

> Sorry, here's the link to the RS page too: > > http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6728997 > > I believe this module uses the Silicon Labs Si4022 chip. This would be great if they had an FCC modular transmitter certification. In an email I got from RF Solutions yesterday, they said: This unit has not undergone any FCC approvals, though it should be compliant and therefore should pass tests. As far as I was aware modules on their own cannot be FCC approved as the function and use of them have not been specified. There ARE, of course, FCC modular transmitter certifications (see http://louise.hallikainen.org/FCC/FccRules/2010/15/212/ ), which the Microchip Zigbee and various manufacturers' WiFi modules have. Thanks for the comment, though! Keep them coming! Harold -- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available!

The trick is that the antenna has to already be integrated into the module so you get FCC cert without testing? You were looking for 915Mhz but the Microchip part is 2.4Ghz. If frequency isn't important can you use something in the 433Mhz range like a garage door opener without the encoder chip? Since data is uni-directional how do you account for lost packets? thanks chuckc On 7/8/2010 4:42 PM, Harold Hallikainen wrote: {Quote hidden}> I need a one way RF link. I'm considering use of 915MHz, but I can not > find any transmitters with FCC modular transmitter certifications > (http://louise.hallikainen.org/FCC/FccRules/2010/15/212/ ). > > Section 3.1 of ww1.microchip.com/downloads/en/DeviceDoc/70329b.pdf > states that the MRF24J40MA has certification as a modular transmitter. > > I COULD go Zigbee all the way, except that the "receivers" would generally > need to transmit back to the "transmitter" where the data originates. > Section 3.1.1 of the datasheet requires the antenna be 20cm or more away > from people. This disallows a handheld or portable "receiver." > > So, what about the possibility of operating one MRF24J40MA as a > transmitter and multiple MRF24J40MA modules as receivers where the > receivers NEVER transmit? Has anyone tried anything like this? Is it a > good or bad idea? > > THANKS! > > > Harold > > >

> The trick is that the antenna has to already be integrated into the > module so you get FCC cert without testing? > > You were looking for 915Mhz but the Microchip part is 2.4Ghz. > If frequency isn't important can you use something in the 433Mhz range > like a garage door opener without the encoder chip? > Since data is uni-directional how do you account for lost packets? > > thanks > chuckc That's correct, FCC modular transmitter certification requires an integrated antenna or approval with a specific antenna. As I recall, you are allowed to substitute another antenna of the same type with equal or less gain. I'm not really concerned about the frequency. The datarate is 10kbps. Data is transmitted repeatedly with CRC for error detection, so lost or erroneous packets are ignored. Looking around for FCC certified modular transmitters, they generally seem to Zigbee or WiFi transceivers. All the ones I've found also have the requirement that the antenna be 20cm away from people. A pure receiver would not have this limitation. So, that's why I'm asking about use of the Microchip Zigbee modules in a one way transmitter to many receivers configuration. THANKS for the comments! Harold -- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available!

Charles Craft wrote: > The trick is that the antenna has to already be integrated into the > module so you get FCC cert without testing? You can also get modules approved for specific antenna models. A number of WiFi modules are available that way with FCC approval. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000.

----- Original Message ----- From: "Harold Hallikainen" <haroldKILLspamhallikainen.org> To: "Pic List" <.....piclistKILLspam.....mit.edu> Sent: Thursday, July 08, 2010 4:42 PM Subject: [EE] Use of Zigbee modules for one way link? > > I need a one way RF <snip> {Quote hidden}> > So, what about the possibility of operating one MRF24J40MA as a > transmitter and multiple MRF24J40MA modules as receivers where the > receivers NEVER transmit? Has anyone tried anything like this? Is it a > good or bad idea? > > THANKS! > > > Harold > Harold, If I understand what you want to do, I believe it has been done on a small scale. Students at Old Dominion University (Norfolk, VA) recently successfully used the MRF24J40MA in a master-slave configuration. Presently there are 2 independently-addressable slaves, but 3 more are being added for use as wireless motor controllers. There is a video posted on the microchip site at: http://www.microchip.com/mchptube Good luck with your project. Richard

Harold Hallikainen wrote: {Quote hidden}>> The trick is that the antenna has to already be integrated into the >> module so you get FCC cert without testing? >> >> You were looking for 915Mhz but the Microchip part is 2.4Ghz. >> If frequency isn't important can you use something in the 433Mhz range >> like a garage door opener without the encoder chip? >> Since data is uni-directional how do you account for lost packets? >> >> thanks >> chuckc > > That's correct, FCC modular transmitter certification requires an > integrated antenna or approval with a specific antenna. As I recall, you > are allowed to substitute another antenna of the same type with equal or > less gain. > > I'm not really concerned about the frequency. The datarate is 10kbps. Data > is transmitted repeatedly with CRC for error detection, so lost or > erroneous packets are ignored. Looking around for FCC certified modular > transmitters, they generally seem to Zigbee or WiFi transceivers. All the > ones I've found also have the requirement that the antenna be 20cm away > from people. A pure receiver would not have this limitation. So, that's > why I'm asking about use of the Microchip Zigbee modules in a one way > transmitter to many receivers configuration. Harold, why Zigbee? Why not one of Linx modules -- you don't want to implement the protocol? Vitaliy

----- Original Message ----- From: "Vitaliy" <EraseMEpiclistspam_OUTTakeThisOuTmaksimov.org> To: "Microcontroller discussion list - Public." <piclistspam_OUTmit.edu> Sent: Thursday, July 08, 2010 3:47 PM Subject: Re: [EE] Use of Zigbee modules for one way link? {Quote hidden}> Harold Hallikainen wrote: >>> The trick is that the antenna has to already be integrated into the >>> module so you get FCC cert without testing? >>> >>> You were looking for 915Mhz but the Microchip part is 2.4Ghz. >>> If frequency isn't important can you use something in the 433Mhz range >>> like a garage door opener without the encoder chip? >>> Since data is uni-directional how do you account for lost packets? >>> >>> thanks >>> chuckc >> >> That's correct, FCC modular transmitter certification requires an >> integrated antenna or approval with a specific antenna. As I recall, you >> are allowed to substitute another antenna of the same type with equal or >> less gain. >> >> I'm not really concerned about the frequency. The datarate is 10kbps. Data >> is transmitted repeatedly with CRC for error detection, so lost or >> erroneous packets are ignored. Looking around for FCC certified modular >> transmitters, they generally seem to Zigbee or WiFi transceivers. All the >> ones I've found also have the requirement that the antenna be 20cm away >> from people. A pure receiver would not have this limitation. So, that's >> why I'm asking about use of the Microchip Zigbee modules in a one way >> transmitter to many receivers configuration. > > Harold, why Zigbee? Why not one of Linx modules -- you don't want to > implement the protocol? Linx has a nice selection of RF modules, and www.rfdigital.com/?targetpage=item&filterpn=RFD21733 has some you might also want to consider. Regards, Bruce @spam@techKILLspamrentron.com

Could you not turn down the TX power of the module and it would then be OK to have it closer than 20cm to a person? As for using Zigbee one-way: Zigbee is a protocol layer on top of the IEEE 802.15.4 physical/link layer. Most Zigbee modules will work in a dumbed-down mode where they are only using 802.15.4. In that mode, you can usually turn retries down to 0 so it won't continue to try to transmit a packet if it doesn't get a response. Similarly, on the RX side, you could make some adjustments to prevent transmit (like setting the channel clear threshold so low that it always thinks the channel is busy). Sean On Thu, Jul 8, 2010 at 4:42 PM, Harold Hallikainen <KILLspamharoldKILLspamhallikainen.org> wrote: {Quote hidden}> > I need a one way RF link. I'm considering use of 915MHz, but I can not > find any transmitters with FCC modular transmitter certifications > (http://louise.hallikainen.org/FCC/FccRules/2010/15/212/ ). > > Section 3.1 of ww1.microchip.com/downloads/en/DeviceDoc/70329b.pdf > states that the MRF24J40MA has certification as a modular transmitter. > > I COULD go Zigbee all the way, except that the "receivers" would generally > need to transmit back to the "transmitter" where the data originates. > Section 3.1.1 of the datasheet requires the antenna be 20cm or more away > from people. This disallows a handheld or portable "receiver." > > So, what about the possibility of operating one MRF24J40MA as a > transmitter and multiple MRF24J40MA modules as receivers where the > receivers NEVER transmit? Has anyone tried anything like this? Is it a > good or bad idea? > > THANKS! > > > Harold > > > -- > FCC Rules Updated Daily at http://www.hallikainen.com - Advertising > opportunities available! > > > > -- > FCC Rules Updated Daily at http://www.hallikainen.com - Advertising > opportunities available! > -

> > Linx has a nice selection of RF modules, and > www.rfdigital.com/?targetpage=item&filterpn=RFD21733 > has some you might also want to consider. > > Regards, > > Bruce > RemoveMEtechTakeThisOuTrentron.com Thanks for all the comments thus far! Here are some reply comments: 1. Wi-Fi modules seem to also have the 20cm antenna to person requirement as a condition of their FCC approval. Their power consumption is also pretty high. 2. I really only need to get data from here to there over 100 feet or so. The Si4022 and Si4322 would do great if I didn't have to deal with FCC certification of the transmitter. 3. The RF Digital transceiver looks interesting, especially if I can set it up to operate in one direction only. I have to read more about it. 4. The Microchip Zigbee modules are nice FCC certified modular transmitters, but also contain the 20cm requirement. However, I'm thinking that if I only transmit one way (it's a broadcast transmission from one unit to many), the 20cm requirement would not apply on units that are not transmitting. I'll look a bit more at RF digital tomorrow. THANKS! Harold 3. I don't think any of the Lynx Technologies modules have FCC certification. Here's a quote from one of their datasheets: "Linx RF modules are designed as component devices that require external components to function. The modules are intended to allow for full Part 15 compliance; however, they are not approved by the FCC or any other agency worldwide. The purchaser understands that approvals may be required prior to the sale or operation of the device, and agrees to utilize the component in keeping with all laws governing its use in the country of operation." -- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available!

Harold Hallikainen wrote: > "Linx RF modules are designed as component devices that require external > components to function. The modules are intended to allow for full Part 15 > compliance; however, they are not approved by the FCC or any other agency > worldwide. The purchaser understands that approvals may be required prior > to the sale or operation of the device, and agrees to utilize the > component in keeping with all laws governing its use in the country of > operation." Is this a low volume product? "How much does FCC certification cost? This depends on how much you have the test lab do. Full transmitter and receiver testing can cost around $5,000, transmitter only around $3,500, and the receiver about $1,500. If testing for other countries, such as Industry Canada or European CE, is desired, then the costs will go up, but will not generally double. The FCC has authorized the test labs to issue identity numbers on its behalf so the testing can usually be done in about a week, depending on the backlog of the test lab. Linx maintains a close working relationship with Compatible Electronics (http://www.celectronics.com) who extends excellent service and special pricing to Linx customers." http://www.linxtechnologies.com/Support/Knowledgebase/FCC/?Article=How+much+does+FCC+certification+cost%3F

> Is this a low volume product? > > "How much does FCC certification cost? > This depends on how much you have the test lab do. Full transmitter and > receiver testing can cost around $5,000, transmitter only around $3,500, > and > the receiver about $1,500. If testing for other countries, such as > Industry > Canada or European CE, is desired, then the costs will go up, but will not > generally double. The FCC has authorized the test labs to issue identity > numbers on its behalf so the testing can usually be done in about a week, > depending on the backlog of the test lab. Linx maintains a close working > relationship with Compatible Electronics (http://www.celectronics.com) who > extends > excellent service and special pricing to Linx customers." > > http://www.linxtechnologies.com/Support/Knowledgebase/FCC/?Article=How+much+does+FCC+certification+cost%3F > Good information. I thought it would be more than that. That looks affordable. I'll look at Lynx some more. THANKS! Harold -- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available!