Zigbee versus BT 4.0 (LE)

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Looking at a possible "cable replacement" project, and from a quick look round the web, it would seem that BT 4.0 is cheaper han Zigbee, even though Zigbee is designed to be simpler.
Is this just market forces, a consequence of BT 4.0 being a more mainstream product?

Four legs good, two legs bad, three legs stable.

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They have two different target goals.

Zigbee and siblings (802.15.4) is defined for low power, relatively low data rates. The example application is wireless battery powered thermostat.

BT is defined for high data rate, relatively short range. Think digital audio. And wireless mouse or keyboard. Low latency.

BT is in almost every modern computer because of the wireless keyboard or mouse thing. Production of zigbee, et al, chips is probably an order of magnitude smaller, if not less.

Jim

 

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Actually, BT 4.0 is designed for very low power, low latency "connectionless"(i.e. it doesn't have to keep the channel open, but can go to sleep for long periods) use, so the comparison is valid.

Your remarks are correct when it comes to traditional Bluetooth.
Likewise, BT 4.0 (or BT LE) is not in every modern computer yet, and it has not yet been incorporated into Android very successfully, although it will probably happen soon.
It is in the latest iThings.

Four legs good, two legs bad, three legs stable.

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One (or likely some) BT 4 vendor states Android and iOS integration.
Throughput, latency, and power requirements will aid in the selection process.
There are some 802.11g products that can run on a lithium (primary or rechargeable) cell for quite some time.
Refs.
Bluetooth LE Solutions for Personal Health Devices by Stephen Evanczuk (Digi-Key, 6/21/2012).
Bluetooth Low-Energy Technology Isn’t Just Another Bluetooth Revision – It’s a Whole New Technology by Rolf Nilsson and Bill Saltzstein (connectBlue) (Digi-Key, 9/13/2012).
Atmel AT02509: In House Unit with Bluetooth Low Energy Module Hardware User Guide (Atmel)
NEW PRODUCT – Bluetooth 4.0 USB Module (v2.1 Back-Compatible) (Google+, Adafruit Industries; Apr 23, 2013).

"Dare to be naïve." - Buckminster Fuller

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John_A_Brown wrote:
... even though Zigbee is designed to be simpler.
Have you considered Atmel Lightweight Mesh?
The Lightweight Mesh WSNDemo application does some serial via wireless.
Zigbee will have a greater capability.
Atmel BitCloud does have some Zigbee RF4CE for serial applications and a bridge application to other networks.
Refs.
Atmel AVR2131: Lightweight Mesh Getting Started Guide
Atmel Software Framework, Applications - select Wireless in Category and search for 'serial'.
AVR2102: RF4Control - User Guide

"Dare to be naïve." - Buckminster Fuller

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I will look into it, as always, price is the thing.
Many thanks for the suggestions.

John

Four legs good, two legs bad, three legs stable.

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If you have control of both ends, maybe the incredibly cheap "NRF24L01" modules will do. Once I learned the difference between input and output, they were very easy to use.

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Torby wrote:
If you have control of both ends, maybe the incredibly cheap "NRF24L01" modules will do. Once I learned the difference between input and output, they were very easy to use.

Yes, I've used those before. I was hoping to use BT 4.0 as I think it could be big, so this first project would be a useful jumping off point.

John

Four legs good, two legs bad, three legs stable.

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John_A_Brown wrote:
Likewise, BT 4.0 (or BT LE) is not in every modern computer yet, and it has not yet been incorporated into Android very successfully, although it will probably happen soon.
Android joins the Bluetooth low-energy movement by Sid Shaw (Texas Instruments E2E, May 15 2013).

"Dare to be naïve." - Buckminster Fuller

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Don't confuse Zigbee with IEEE 802.15.4.

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John_A_Brown wrote:
I will look into it, as always, price is the thing.
Many thanks for the suggestions.

John

Sometimes, use of standards trumps price.

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I've just finished reading through the Bluetooth Low Energy Developer's Handbook:

http://www.amazon.ca/Bluetooth-Low-Energy-Developers-Handbook/dp/013288836X

I picked the book up because, looking through a few online information sources, I was a bit baffled about what exactly BLE was.

I don't think I would recommend BLE for cable replacement. As mentioned, it's got quite a different data model compared to classic Bluetooth--more of a client-server model for accessing a device's state. This is appropriate for things like heart rate monitors, but I don't think it's a good fit for serial data.

I've used classic Bluetooth as a cable replacement before, using the RN-41 module:

http://www.rovingnetworks.com/products/RN41

The module made it very easy to set up serial communication between two devices. If I was looking for a straight-up serial replacement, this is the first thing I would try.

Michael

Edit: Doing a bit more searching specifically about cable replacement, it looks like you might be able to manage it with a couple of BLE112 modules using their BGScript language to program each module. More information on that here:

http://ezoelectro.narod.ru/doc-pdf/ble112/BLE_Application_Note_CRP_Sensor.pdf

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Also as far as I have seen info on it, blue tooth low energy is not yet a standard and every manufacturer has its own implementation.
This means when you star with a manufacturer now in future your device might not be standard compatible and thus you have to update your design.

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Quote:

Edit: Doing a bit more searching specifically about cable replacement, it looks like you might be able to manage it with a couple of BLE112 modules using their BGScript language to program each module. More information on that here:

I already have a couple of BLE112 modules, a programmer/debugger and a couple of BlueGiga BT 4.0 USB dongles on my desk, just needing to find the time now.

John

Four legs good, two legs bad, three legs stable.

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meslomp wrote:
Also as far as I have seen info on it, blue tooth low energy is not yet a standard and every manufacturer has its own implementation.

Much of it is standardized--protocols and such--but it seems like the list of official "profiles" and "services" is still quite small.

My impression is that BLE doesn't force you to use the standard profiles/services. There are a couple of main advantages: shorter keys (2 bytes vs. 16 bytes, if memory serves) mean less radio usage; and of course using a standard profile/service would make your device interoperable with any other device that supports the same profile/service. However, for a lot of projects, neither of these is a deal breaker.

Michael