Ulf Samuelsson wrote:> linnix skrev 2011-01-06 21:51: > >> On Jan 6, 11:25 am, "langw...@fonz.dk"<langw...@fonz.dk> wrote: >> >>> On 6 Jan., 05:10, linnix<m...@linnix.info-for.us> wrote: >>> >>> >>> >>>> On Jan 5, 7:48 pm, Mostafa Kassem<m.kassem...@gmail.com> wrote: >>> >>> >>>>> On 1/5/2011 10:09 PM, Vladimir Vassilevsky wrote: >>> >>> >>>>>> There is a network of ~100 wireless sensors, communicating to a >>>>>> single >>>>>> host. All sensors are located within ~50..100m from the host in the >>>>>> typical urban environment. Ideally, it would be desirable to poll >>>>>> each >>>>>> sensor at least 10 times/sec. When polling the sensors, we have to >>>>>> get >>>>>> just several bits of the status information from each sensor. >>> >>> >>>>>> Problem: as sensors are battery powered, the average power >>>>>> consumption >>>>>> of the entire communication part of a sensor is limited to ~ 10mW >>>>>> max. >>> >>> >>>>>> Is there a wireless technology/modules on the market that would allow >>>>>> such power budget? >>> >>> >>>>>> Would it be possible to develop such technology using existing >>>>>> transceiver ICs or modules? >>> >>>>>> (Cost, operating band, compliance, acceptance, etc. are outside of >>>>>> consideration at this point). >>> >>> > The ATmega128RFA1 (ZigBee + 128kB Flash AVR) uses about 26 mW during > transmission and a little bit lower during reception.Dear Ulf @ All, I reviewed several low power wireless chipsets from different vendors. They typically drain about 20mA @ 3.3V when in the active Rx or Tx mode, and less then 1mA in sleep. Switching from sleep to active incurs the overhead of several milliseconds; unfortunately none of the transceivers retain the bit synchronization between the packets; there is no easy way to synchronize the nodes to the master to a fraction of the bit interval. As noted by David and Mark, it could be possible to fit the 10mW constraint if the system cycle time is several seconds; but it is hardly feasible with the cycle time < 1 sec. Next question: are there any off-the-shelf wireless modules that could allow for the ~1/100 duty cycle operation with ~10ms packets with the average power consumption ~10mW ? Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Feasibility of the VERY low power wireless network?
Started by ●January 5, 2011
Reply by ●January 7, 20112011-01-07
Reply by ●January 7, 20112011-01-07
On Jan 7, 11:14=A0am, Vladimir Vassilevsky <nos...@nowhere.com> wrote:> Ulf Samuelsson wrote: > > linnix skrev 2011-01-06 21:51: > > >> On Jan 6, 11:25 am, "langw...@fonz.dk"<langw...@fonz.dk> =A0wrote: > > >>> On 6 Jan., 05:10, linnix<m...@linnix.info-for.us> =A0wrote: > > >>>> On Jan 5, 7:48 pm, Mostafa Kassem<m.kassem...@gmail.com> =A0wrote: > > >>>>> On 1/5/2011 10:09 PM, Vladimir Vassilevsky wrote: > > >>>>>> There is a network of ~100 wireless sensors, communicating to a > >>>>>> single > >>>>>> host. All sensors are located within ~50..100m from the host in th=e> >>>>>> typical urban environment. Ideally, it would be desirable to poll > >>>>>> each > >>>>>> sensor at least 10 times/sec. When polling the sensors, we have to > >>>>>> get > >>>>>> just several bits of the status information from each sensor. > > >>>>>> Problem: as sensors are battery powered, the average power > >>>>>> consumption > >>>>>> of the entire communication part of a sensor is limited to ~ 10mW > >>>>>> max. > > >>>>>> Is there a wireless technology/modules on the market that would al=low> >>>>>> such power budget? > > >>>>>> Would it be possible to develop such technology using existing > >>>>>> transceiver ICs or modules? > > >>>>>> (Cost, operating band, compliance, acceptance, etc. are outside of > >>>>>> consideration at this point). > > > The ATmega128RFA1 (ZigBee + 128kB Flash AVR) uses about 26 mW during > > transmission and a little bit lower during reception. > > Dear Ulf @ All, > > I reviewed several low power wireless chipsets from different vendors. > They typically drain about 20mA @ 3.3V when in the active Rx or Tx mode, > and less then 1mA in sleep. Switching from sleep to active incurs the > overhead of several milliseconds; unfortunately none of the transceivers > retain the bit synchronization between the packets; there is no easy way > to synchronize the nodes to the master to a fraction of the bit > interval. As noted by David and Mark, it could be possible to fit the > 10mW constraint if the system cycle time is several seconds; but it is > hardly feasible with the cycle time < 1 sec.This requirement is very difficult to achieve. Just curious, what application requires such tight timing?
Reply by ●January 7, 20112011-01-07
Vladimir Vassilevsky skrev 2011-01-07 20:14:> > > Ulf Samuelsson wrote: > >> linnix skrev 2011-01-06 21:51: >> >>> On Jan 6, 11:25 am, "langw...@fonz.dk"<langw...@fonz.dk> wrote: >>> >>>> On 6 Jan., 05:10, linnix<m...@linnix.info-for.us> wrote: >>>> >>>> >>>> >>>>> On Jan 5, 7:48 pm, Mostafa Kassem<m.kassem...@gmail.com> wrote: >>>> >>>> >>>>>> On 1/5/2011 10:09 PM, Vladimir Vassilevsky wrote: >>>> >>>> >>>>>>> There is a network of ~100 wireless sensors, communicating to a >>>>>>> single >>>>>>> host. All sensors are located within ~50..100m from the host in the >>>>>>> typical urban environment. Ideally, it would be desirable to poll >>>>>>> each >>>>>>> sensor at least 10 times/sec. When polling the sensors, we have >>>>>>> to get >>>>>>> just several bits of the status information from each sensor. >>>> >>>> >>>>>>> Problem: as sensors are battery powered, the average power >>>>>>> consumption >>>>>>> of the entire communication part of a sensor is limited to ~ 10mW >>>>>>> max. >>>> >>>> >>>>>>> Is there a wireless technology/modules on the market that would >>>>>>> allow >>>>>>> such power budget? >>>> >>>> >>>>>>> Would it be possible to develop such technology using existing >>>>>>> transceiver ICs or modules? >>>> >>>>>>> (Cost, operating band, compliance, acceptance, etc. are outside of >>>>>>> consideration at this point). >>>> >>>> >> The ATmega128RFA1 (ZigBee + 128kB Flash AVR) uses about 26 mW during >> transmission and a little bit lower during reception. > > Dear Ulf @ All, > > I reviewed several low power wireless chipsets from different vendors. > They typically drain about 20mA @ 3.3V when in the active Rx or Tx mode, > and less then 1mA in sleep. Switching from sleep to active incurs the > overhead of several milliseconds; unfortunately none of the transceivers > retain the bit synchronization between the packets; there is no easy way > to synchronize the nodes to the master to a fraction of the bit > interval. As noted by David and Mark, it could be possible to fit the > 10mW constraint if the system cycle time is several seconds; but it is > hardly feasible with the cycle time < 1 sec. > > Next question: are there any off-the-shelf wireless modules that could > allow for the ~1/100 duty cycle operation with ~10ms packets with the > average power consumption ~10mW ? >If you are desperate for good power figures, then you should consider running at 1.8V. The ATmega128RFA1 power consumption in sleep is 0.4 mA * 1.8V so less than 1 mW. With 30 mW during transmit, you can have a duty cycle of almost 33% to still achieve Link budget is 103,5 dBm which is also quite good. If you can live with a link budget of 97,5 (still better than most competition), then the transmit power goes down to < 15 mW. Did not check the Atmel ZigBit modules (which are two chips solutions) but they should be similar in power consumption.> > Vladimir Vassilevsky > DSP and Mixed Signal Design Consultant > http://www.abvolt.com > > > >-- Best Regards Ulf Samuelsson These are my own personal opinions, which may or may not be shared by my employer Atmel Nordic AB
Reply by ●January 8, 20112011-01-08
On Jan 7, 9:59 am, Chris_99 <cgr...@gmail.com> wrote:> On Jan 6, 8:21 pm, rickman <gnu...@gmail.com> wrote: > > > > > On Jan 5, 11:58 pm, Vladimir Vassilevsky <nos...@nowhere.com> wrote: > > > > hamilton wrote: > > > > On 1/5/2011 8:09 PM, Vladimir Vassilevsky wrote: > > > > >> There is a network of ~100 wireless sensors, communicating to a single > > > >> host. All sensors are located within ~50..100m from the host in the > > > >> typical urban environment. Ideally, it would be desirable to poll each > > > >> sensor at least 10 times/sec. When polling the sensors, we have to get > > > >> just several bits of the status information from each sensor. > > > > >> Problem: as sensors are battery powered, the average power consumption > > > >> of the entire communication part of a sensor is limited to ~ 10mW max. > > > > >> Is there a wireless technology/modules on the market that would allow > > > >> such power budget? > > > > >> Would it be possible to develop such technology using existing > > > >> transceiver ICs or modules? > > > > >> (Cost, operating band, compliance, acceptance, etc. are outside of > > > >> consideration at this point). > > > > >> Vladimir Vassilevsky > > > >> DSP and Mixed Signal Design Consultant > > > >>http://www.abvolt.com > > > > > What is the real time requirement ? > > > > > TinyOS maybe what your looking for. > > > > > A google search for "wireless sensor networks" found this: > > > >https://secure.wikimedia.org/wikipedia/en/wiki/Wireless_sensor_network > > > > > as well as almost 1 million others. > > > > > hamilton > > > > Idiot > > > Why does anyone respond to this guy? When others ask questions rather > > than give even the least answer or any encouragement he derides them. > > When he asks questions and others respond, if he doesn't like the > > response, he derides them rather than thanking them and moving on or > > even just ignoring them. > > > Why does anyone think this guy deserves any sort of response when he > > is asking for help? > > > Rick- Hide quoted text - > > > - Show quoted text - > > Actually, even though the OP is a bit surly, his point-of-view and > statements are often very valuable to me. > Secondarily, I also thought the "1 million google responses" thing was > small-brained since the > post started out looking for very low power wireless and not wireless > in general."A bit surly"??? You mean like Ted Bundy was a bit rough on women, or the Japanese are a bit aggressive with whales, or the way the Taliban is a bit ugly with women? Yeah, otherwise they are all really great guys and there is no reason to not accept their bad side. Heck, everyone has a bad side, no? Rick
Reply by ●January 8, 20112011-01-08
On Sat, 08 Jan 2011 01:35:18 +0100, Ulf Samuelsson <ulf@invalid.atmel.com> wrote:>Link budget is 103,5 dBm which is also quite good. >If you can live with a link budget of 97,5 (still better than most >competition), then the transmit power goes down to < 15 mW.While it might be possible to calculate the link budget for an interplanetary space link with an accuracy of a fraction of an dB, such accurate (and successful) predictions in ground based systems should IMHO be awarded with the Nobel prize :-). In real world urban conditions, the path loss will typically increase by 10-15 dB each time the distance doubles (contrary to 6 dB for free space). I first assumed that you are simply talking about the difference between the Tx/Rx power, but the figures does not make any sense. If 103.5 dBm actually refers to -103.5 dBm receiver sensitivity and the thermal noise at room temperature id -174 dBm/Hz thus bandwidths larger than 1 MHz should be assumed, much larger than the OP needed (10-50 kHz at most).
Reply by ●January 8, 20112011-01-08
On Jan 7, 4:35=A0pm, Ulf Samuelsson <u...@invalid.atmel.com> wrote:> Vladimir Vassilevsky skrev 2011-01-07 20:14: > > > > > > > Ulf Samuelsson wrote: > > >> linnix skrev 2011-01-06 21:51: > > >>> On Jan 6, 11:25 am, "langw...@fonz.dk"<langw...@fonz.dk> wrote: > > >>>> On 6 Jan., 05:10, linnix<m...@linnix.info-for.us> wrote: > > >>>>> On Jan 5, 7:48 pm, Mostafa Kassem<m.kassem...@gmail.com> wrote: > > >>>>>> On 1/5/2011 10:09 PM, Vladimir Vassilevsky wrote: > > >>>>>>> There is a network of ~100 wireless sensors, communicating to a > >>>>>>> single > >>>>>>> host. All sensors are located within ~50..100m from the host in t=he> >>>>>>> typical urban environment. Ideally, it would be desirable to poll > >>>>>>> each > >>>>>>> sensor at least 10 times/sec. When polling the sensors, we have > >>>>>>> to get > >>>>>>> just several bits of the status information from each sensor. > > >>>>>>> Problem: as sensors are battery powered, the average power > >>>>>>> consumption > >>>>>>> of the entire communication part of a sensor is limited to ~ 10mW > >>>>>>> max. > > >>>>>>> Is there a wireless technology/modules on the market that would > >>>>>>> allow > >>>>>>> such power budget? > > >>>>>>> Would it be possible to develop such technology using existing > >>>>>>> transceiver ICs or modules? > > >>>>>>> (Cost, operating band, compliance, acceptance, etc. are outside o=f> >>>>>>> consideration at this point). > > >> The ATmega128RFA1 (ZigBee + 128kB Flash AVR) uses about 26 mW during > >> transmission and a little bit lower during reception. > > > Dear Ulf @ All, > > > I reviewed several low power wireless chipsets from different vendors. > > They typically drain about 20mA @ 3.3V when in the active Rx or Tx mode=,> > and less then 1mA in sleep. Switching from sleep to active incurs the > > overhead of several milliseconds; unfortunately none of the transceiver=s> > retain the bit synchronization between the packets; there is no easy wa=y> > to synchronize the nodes to the master to a fraction of the bit > > interval. As noted by David and Mark, it could be possible to fit the > > 10mW constraint if the system cycle time is several seconds; but it is > > hardly feasible with the cycle time < 1 sec. > > > Next question: are there any off-the-shelf wireless modules that could > > allow for the ~1/100 duty cycle operation with ~10ms packets with the > > average power consumption ~10mW ? > > If you are desperate for good power figures, then > you should consider running at 1.8V. > > The ATmega128RFA1 power consumption in sleep is 0.4 mA * 1.8V > so less than 1 mW. > With 30 mW during transmit, you can have a duty cycle of almost 33% > to still achieveI read the whole datasheet for Atmega128rfa1. Other than the standard AVR stuffs, there is not much information on the RF controller. Perhaps someone can answer my questions: 1. Is the Radio permanently attached to the UART? 2. Is the Radio permanently attached to the SPI? 3. Can the radio be enable/disable on demand? 4. Can the transmitter power be adjusted/changed? 5. Can the frequency be adjusted/changed? Are there other docs to address these issues?
Reply by ●January 8, 20112011-01-08
In article <53ded77f-29f0-4307-a923-e6e4afac23d3 @r19g2000prm.googlegroups.com>, me@linnix.info-for.us says...> > On Jan 7, 11:14�am, Vladimir Vassilevsky <nos...@nowhere.com> wrote: > > Ulf Samuelsson wrote: > > > linnix skrev 2011-01-06 21:51: > > > > >> On Jan 6, 11:25 am, "langw...@fonz.dk"<langw...@fonz.dk> �wrote: > > > > >>> On 6 Jan., 05:10, linnix<m...@linnix.info-for.us> �wrote: > > > > >>>> On Jan 5, 7:48 pm, Mostafa Kassem<m.kassem...@gmail.com> �wrote: > > > > >>>>> On 1/5/2011 10:09 PM, Vladimir Vassilevsky wrote: > > > > >>>>>> There is a network of ~100 wireless sensors, communicating to a > > >>>>>> single > > >>>>>> host. All sensors are located within ~50..100m from the host in the > > >>>>>> typical urban environment. Ideally, it would be desirable to poll > > >>>>>> each > > >>>>>> sensor at least 10 times/sec. When polling the sensors, we have to > > >>>>>> get > > >>>>>> just several bits of the status information from each sensor. > > > > >>>>>> Problem: as sensors are battery powered, the average power > > >>>>>> consumption > > >>>>>> of the entire communication part of a sensor is limited to ~ 10mW > > >>>>>> max. > > > > >>>>>> Is there a wireless technology/modules on the market that would allow > > >>>>>> such power budget? > > > > >>>>>> Would it be possible to develop such technology using existing > > >>>>>> transceiver ICs or modules? > > > > >>>>>> (Cost, operating band, compliance, acceptance, etc. are outside of > > >>>>>> consideration at this point). > > > > > The ATmega128RFA1 (ZigBee + 128kB Flash AVR) uses about 26 mW during > > > transmission and a little bit lower during reception. > > > > Dear Ulf @ All, > > > > I reviewed several low power wireless chipsets from different vendors. > > They typically drain about 20mA @ 3.3V when in the active Rx or Tx mode, > > and less then 1mA in sleep. Switching from sleep to active incurs the > > overhead of several milliseconds; unfortunately none of the transceivers > > retain the bit synchronization between the packets; there is no easy way > > to synchronize the nodes to the master to a fraction of the bit > > interval. As noted by David and Mark, it could be possible to fit the > > 10mW constraint if the system cycle time is several seconds; but it is > > hardly feasible with the cycle time < 1 sec. > > This requirement is very difficult to achieve. Just curious, what > application requires such tight timing?I can envision one: A security system where an intrusion sensor is triggered and the master system then wants to zoom a surveillance camera in on that particular location. If the system has a latency of 10 seconds, you might get a high-res picture of a broken window minus the ski-masked perp. Mark Borgerson
Reply by ●January 8, 20112011-01-08
On Jan 8, 9:45=A0am, Mark Borgerson <mborger...@comcast.net> wrote:> In article <53ded77f-29f0-4307-a923-e6e4afac23d3 > @r19g2000prm.googlegroups.com>, m...@linnix.info-for.us says... > > > > > > > On Jan 7, 11:14 am, Vladimir Vassilevsky <nos...@nowhere.com> wrote: > > > Ulf Samuelsson wrote: > > > > linnix skrev 2011-01-06 21:51: > > > > >> On Jan 6, 11:25 am, "langw...@fonz.dk"<langw...@fonz.dk> wrote: > > > > >>> On 6 Jan., 05:10, linnix<m...@linnix.info-for.us> wrote: > > > > >>>> On Jan 5, 7:48 pm, Mostafa Kassem<m.kassem...@gmail.com> wrote: > > > > >>>>> On 1/5/2011 10:09 PM, Vladimir Vassilevsky wrote: > > > > >>>>>> There is a network of ~100 wireless sensors, communicating to =a> > > >>>>>> single > > > >>>>>> host. All sensors are located within ~50..100m from the host i=n the> > > >>>>>> typical urban environment. Ideally, it would be desirable to p=oll> > > >>>>>> each > > > >>>>>> sensor at least 10 times/sec. When polling the sensors, we hav=e to> > > >>>>>> get > > > >>>>>> just several bits of the status information from each sensor. > > > > >>>>>> Problem: as sensors are battery powered, the average power > > > >>>>>> consumption > > > >>>>>> of the entire communication part of a sensor is limited to ~ 1=0mW> > > >>>>>> max. > > > > >>>>>> Is there a wireless technology/modules on the market that woul=d allow> > > >>>>>> such power budget? > > > > >>>>>> Would it be possible to develop such technology using existing > > > >>>>>> transceiver ICs or modules? > > > > >>>>>> (Cost, operating band, compliance, acceptance, etc. are outsid=e of> > > >>>>>> consideration at this point). > > > > > The ATmega128RFA1 (ZigBee + 128kB Flash AVR) uses about 26 mW durin=g> > > > transmission and a little bit lower during reception. > > > > Dear Ulf @ All, > > > > I reviewed several low power wireless chipsets from different vendors=.> > > They typically drain about 20mA @ 3.3V when in the active Rx or Tx mo=de,> > > and less then 1mA in sleep. Switching from sleep to active incurs the > > > overhead of several milliseconds; unfortunately none of the transceiv=ers> > > retain the bit synchronization between the packets; there is no easy =way> > > to synchronize the nodes to the master to a fraction of the bit > > > interval. As noted by David and Mark, it could be possible to fit the > > > 10mW constraint if the system cycle time is several seconds; but it i=s> > > hardly feasible with the cycle time < 1 sec. > > > This requirement is very difficult to achieve. =A0Just curious, what > > application requires such tight timing? > > I can envision one: =A0A security system where an intrusion sensor is > triggered and the master system then wants to zoom a surveillance > camera in on that particular location. =A0If the system has a latency > of 10 seconds, you might get a high-res picture of a broken window > minus the ski-masked perp.In that case, single on-off transmitters might be more cost effective. You can have all sensors transmitting the same frequency and any one can trigger all cameras in the group. Gate/garage transmitters are dirt cheap.
