Comments on: Vetting DASH7 http://dash7.org/blog/?p=221 long range, low power wireless sensor networking now available Wed, 02 Mar 2011 16:15:43 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Vito http://dash7.org/blog/?p=221&cpage=1#comment-2479 Vito Sat, 26 Jun 2010 21:46:05 +0000 http://dash7.org/blog/?p=221#comment-2479 Hi Pat, Thanks for your reply. We are gathering sensor data from strain gages. Not fast at all. 4 or 5 16-bit readings ever 30 minutes. I still don't see any thing that would work for me from these vendors. They seem to be RFID specific. Hi Pat,

Thanks for your reply. We are gathering sensor data from strain gages. Not fast at all. 4 or 5 16-bit readings ever 30 minutes.

I still don’t see any thing that would work for me from these vendors. They seem to be RFID specific.

]]> By: PatBurns http://dash7.org/blog/?p=221&cpage=1#comment-2400 PatBurns Thu, 17 Jun 2010 22:36:14 +0000 http://dash7.org/blog/?p=221#comment-2400 Vito, What type of data? If video or other heavy streaming, then DASH7 may not be the best fit. DASH7 is an active RFID standard, but increasingly we're veering away from using the term "RFID" to represent the more dynamic characteristics of DASH7 --- longer range, sensor net support, security, etc. So regardless of the term used, the equipment from the above vendors should suit your application fine provided the throughput requirement is not > 28kbps. Vito,

What type of data? If video or other heavy streaming, then DASH7 may not be the best fit.

DASH7 is an active RFID standard, but increasingly we’re veering away from using the term “RFID” to represent the more dynamic characteristics of DASH7 — longer range, sensor net support, security, etc. So regardless of the term used, the equipment from the above vendors should suit your application fine provided the throughput requirement is not > 28kbps.

]]> By: Vito http://dash7.org/blog/?p=221&cpage=1#comment-2340 Vito Sat, 12 Jun 2010 03:02:19 +0000 http://dash7.org/blog/?p=221#comment-2340 Thanks for your quick response Pat. I had looked at these these manufacture's sites already and took another look on your suggestion. Their products are all RFID related. I'm looking for essentially an Ethernet replacement to wirelessly transmit and receive data from 25 remote devices to a master system. The distance is 2500 ft. Preferably the device would have an Ethernet or USB interface. If you or anyone knows of a manufacturer of such a device using DASH 7 technology, I would appreciate a response. Thanks for your quick response Pat. I had looked at these these manufacture’s sites already and took another look on your suggestion. Their products are all RFID related.

I’m looking for essentially an Ethernet replacement to wirelessly transmit and receive data from 25 remote devices to a master system. The distance is 2500 ft. Preferably the device would have an Ethernet or USB interface. If you or anyone knows of a manufacturer of such a device using DASH 7 technology, I would appreciate a response.

]]> By: PatBurns http://dash7.org/blog/?p=221&cpage=1#comment-2325 PatBurns Thu, 10 Jun 2010 05:46:07 +0000 http://dash7.org/blog/?p=221#comment-2325 Vito, I would recommend the following DASH7 vendors that have been actively participating in the DASH7 Alliance test and certification process: www.evigia.com www.identecsolutions.com www.savi.com Each may have a slightly different prescription for your needs depending on the exact use case. More vendors are on the way or others reading this post may want to chime in ... Cheers, Pat Vito,

I would recommend the following DASH7 vendors that have been actively participating in the DASH7 Alliance test and certification process:

http://www.evigia.com
http://www.identecsolutions.com
http://www.savi.com

Each may have a slightly different prescription for your needs depending on the exact use case. More vendors are on the way or others reading this post may want to chime in …

Cheers,

Pat

]]> By: Vito http://dash7.org/blog/?p=221&cpage=1#comment-2322 Vito Thu, 10 Jun 2010 00:59:21 +0000 http://dash7.org/blog/?p=221#comment-2322 OK, I buy in to all the Dash 7 advantages. I'm a systems integrator and need to get data from 25 devices spread over a half a mile. Where are the Dash 7 products. I need gateway or bridges to connect these 25 devices to a master system for data collection. I want to replace Ethernet wiring with Dash 7 wireless. Whatproducts will let me do that? OK, I buy in to all the Dash 7 advantages. I’m a systems integrator and need to get data from 25 devices spread over a half a mile. Where are the Dash 7 products. I need gateway or bridges to connect these 25 devices to a master system for data collection. I want to replace Ethernet wiring with Dash 7 wireless. Whatproducts will let me do that?

]]> By: PatBurns http://dash7.org/blog/?p=221&cpage=1#comment-400 PatBurns Wed, 24 Feb 2010 01:29:39 +0000 http://dash7.org/blog/?p=221#comment-400 Chris, First of all, thanks for commenting. Great to have the de-facto leader of the ZB movement weighing in. The vast majority of the power consumed by a DASH7 (or ZigBee) device is devoted to waiting around (listening) and waiting for data to arrive, independent of the data rate for transmitting a message. So your argument really doesn't stand up. Separately, unless your sensor network is moving lots of video or audio around ---- the exception in most cases we see --- the idea that somehow a sensor network needs a big pipe for transmitting lots of data quickly is really "old school" thinking. DASH7 is ideal for sending sensor messages because the average message size is so small. No need for a firehose when a syringe will do just fine. The fact is, DASH7 draws 10% of the power of ZigBee. You don't need as many DASH7 nodes as ZigBee nodes in a given area given the range advantage, so total cost ownership is far lower both from the standpoint of a device investment but also from the maintenance costs of replacing or recharging batteries. Gotta jump on a plane but can respond more later ... Chris,

First of all, thanks for commenting. Great to have the de-facto leader of the ZB movement weighing in.

The vast majority of the power consumed by a DASH7 (or ZigBee) device is devoted to waiting around (listening) and waiting for data to arrive, independent of the data rate for transmitting a message. So your argument really doesn’t stand up.

Separately, unless your sensor network is moving lots of video or audio around —- the exception in most cases we see — the idea that somehow a sensor network needs a big pipe for transmitting lots of data quickly is really “old school” thinking. DASH7 is ideal for sending sensor messages because the average message size is so small. No need for a firehose when a syringe will do just fine.

The fact is, DASH7 draws 10% of the power of ZigBee. You don’t need as many DASH7 nodes as ZigBee nodes in a given area given the range advantage, so total cost ownership is far lower both from the standpoint of a device investment but also from the maintenance costs of replacing or recharging batteries.

Gotta jump on a plane but can respond more later …

]]> By: Akiba http://dash7.org/blog/?p=221&cpage=1#comment-399 Akiba Tue, 23 Feb 2010 14:53:11 +0000 http://dash7.org/blog/?p=221#comment-399 As the designer that you mentioned that seems to be moving to 900 mhz, I think you might be misunderstanding something. Since I'm designing open source 802.15.4 software, I'm trying to support all the bands that 802.15.4 runs in. Hence, since 868/915 MHz is one of the bands specified for 802.15.4, then I'm starting to play with it. In regards to 433 MHz, you often mention how much better it is in range, but I rarely hear you make the power argument. Since Dash7 at 433 runs roughly 10x slower than 802.15.4, then the amount of power consumed for transferring the same amount of data is roughly 10x as well due to the time that the transceiver needs to stay on. In wireless sensor networks, power is often more important than range, since we're dealing with localized nodes that need to stay alive for long periods of time. As the designer that you mentioned that seems to be moving to 900 mhz, I think you might be misunderstanding something. Since I’m designing open source 802.15.4 software, I’m trying to support all the bands that 802.15.4 runs in. Hence, since 868/915 MHz is one of the bands specified for 802.15.4, then I’m starting to play with it.
In regards to 433 MHz, you often mention how much better it is in range, but I rarely hear you make the power argument. Since Dash7 at 433 runs roughly 10x slower than 802.15.4, then the amount of power consumed for transferring the same amount of data is roughly 10x as well due to the time that the transceiver needs to stay on. In wireless sensor networks, power is often more important than range, since we’re dealing with localized nodes that need to stay alive for long periods of time.

]]> By: Jason Schwarz http://dash7.org/blog/?p=221&cpage=1#comment-372 Jason Schwarz Fri, 19 Feb 2010 03:21:01 +0000 http://dash7.org/blog/?p=221#comment-372 Just curious why you indicate 433 MHz is globally open frequency, when it appears to be allocated to the 70cm amateur radio band in the US? Just curious why you indicate 433 MHz is globally open frequency, when it appears to be allocated to the 70cm amateur radio band in the US?

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