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Simple-to-use ZigBee Hardware
An anonymous reader submits "I thought this was interesting. Up till now, ZigBee was only available as a chipset or some rudimentary modules. Now regular schmucks like me that don't want to mess with a soldering iron can use ZigBee and see if it sucks or not. These radios have a range of almost a mile and cost less than $100. Not bad since nobody else seems to offer anything like this (yet). Now I can get my laptop to communicate with some of my robotics projects without an RS-232 umbilical cord." (WikiPedia's page on ZigBee a is a good way to figure out whether this is interesting to you; in short, a low-power, medium-range radio spec for all sorts of interesting uses.)
"Thank you, Timothy, for adding an explanation of what the heck ZigBee is." That was very pleasant to see.
FYI: These modules uses Freescale's Zigbee chips according to Freescale's press release.
"No soldering required!"
What you say?
"$100!"
At that price, even if I don't know what I doing, move ZigBee!
That's one are I think ZigBee can be very successful. X10 works, but has less than stellar reliability. RadioRA (Lutron I beleive) and the others are properitry and can be quite expensive. Conversely, "anybody" can make a ZigBee compliant device and it should work with any other ZigBee device--even from another manufacturers. This should help to keep ZigBee home automation devices price competitive--at least I hope so.
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According to the link:
"capable of transmitting up to 0.9 miles (1.4 km) in line-of-sight conditions."
According to the wikipedia article:
"Transmission range is between 10 and 75 metres (33~246 feet)."
There is quite a bit of a difference between those two. Is wikipedia out of date, or rfdesign overly optimistic?
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We are working on putting Zigbee modules into devices where I work. The real benefit of them is the power consumption. They are meant to sleep 99% of the time they are out there, only waking up if they have to send data or to check if their host device wants to bug them. The devices these would go in are the kind you put out and forget about, maybe changing batteries every few months.
The biggest problem right now though is that the technology is still rather young and it's not implemented uniformly. One company might have a chip that runs completely differently from the next company.
If you can find a chipset that you are happy with though, 802.15.4 and Zigbee work well for low power, low data style transfers, but be prepared to have to fiddle with 'em to get exactly what you want.
I've used these and Aerocomm at a previous job. They rule, I really wonder why it's not more popular. If you're doing any sort of electronics project with a remote control or a serial cable or anything like that, just use Zigbee instead. It's easy and worth it.
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Especially thos where you only have two weeks and a $100 budget...
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This site has quite a range of wireless communications modules: http://www.sparkfun.com/shop/index.php?shop=1&cart =354104&cat=62&
Coin-size transceivers for $20. There's also Bluetooth modules in case you want to roll your own Bluetooth thingamajig.
Yeah, if only something like this existed.
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First, the outdoor, Line-of-Sight spec is 4000', or slightly over 1km. That doesn't jive w/ the RF performance specs of 100mW EIRP and -100dBm sensitivity, which should be a 10km LOS distance @ 2.4GHz (for the math geeks: Transmit Power (Ptx) - Sensitivity(Prx) = Max Path Loss(Lp). Path Loss(Lp) = 32.44 + 20log10(F(MHz)*D(km)). Do that math and they should be 9.9km). So somewhere they're claiming a false spec, or they're leaving 20dB of path margin to account for rain fade, etc, but I've never known an RF manufacturer to claim less than the best possible, never-really-achivable spec.
Second, that's outdoor LOS. Most of us will never have LOS for a km or beyond. A few applications can have that, but those are usually fixed-site applications where you can put higer gain antennas anyway so distances can go even farther. Most people would use this for indoor communications, which reduces the range considerably, although their 300' indoor range sounds realistic. But why, oh why, would you bother to use ZigBee when these things draw far more current than existing 900MHz and 2.4GHz radios from other vendors.
Zigbee was motivated largely by a need for simplicity and low power in comparison to Bluetooth. But it still looks like a fair bit of work to implement the software stack - not likely to fit comfortably in a tiny micro with only a KB or two of flash. The module linked to from the summary looks like it would take away this problem, but it's huge compared to the hardware I'd want to use it with. I'm hoping this will shrink down to chip size soon, like some of the hardware USB bridge chips that are available now.
There's another interesting new protocol around that is even simpler called ANT. It's proprietary and the only implementation I know of at the moment is the Nordic nRF24AP1 chip, but there's full data available on the thisisant web site. It's so simple that I was able to read and understand the protocol document in one sitting. I'm looking forward to getting my hands on some of these because they look perfect for home made hardware - they're tiny (5mm x 5mm), will work with cheap 8 bit micro's, and the software won't be too complicated.