Wixel Shield: Make your Arduino Wireless!

This is neat -- what sort of modulation does the it support? Is it interoperable with any other types of 2.4 GHz wireless, i.e. Bluetooth, 802.15.4, etc?

Wixels are mainly intended for wireless communication with other Wixels. The Wixel uses the CC2511F32 microcontroller from Texas Instruments, which does not support Bluetooth, 802.15.4, Zigbee, or Wifi. The Wixel is compatible with the CC2500 transceiver, the CC2510Fx family, and the CC2511Fx family of chips from Texas Instruments. All the apps we've written for the Wixel use MSK modulation, but the radio also supports 2-FSK and GFSK modulation. It also supports a wide range of data rates, Manchester encoding, forward error correction, and a host of other options.

  • Ben

if I read this right - it's a replacement for a pair of XBees

or did I read it wrong after all?!?

oh and forgot to ask
will the shield and two wixels deal be available in the UK?
postage from the US is almost as much as the hardware price!!

if I read this right - it's a replacement for a pair of XBees

or did I read it wrong after all?!?

Not quite. The Wixels are designed just to be used in pairs, while the Xbees can be used in a network of more the two. Other then that they are somewhat equivalent.

It depends what you want to do. Typically, people use XBees to make a wireless serial link between two microcontrollers or between a microcontroller and a computer. You can achieve that with a pair of Wixels without writing any code if you use the wireless serial app, so in that sense a pair of Wixels could replace a pair of XBees and save you money. But please note that the XBees work over a longer range than Wixels.

The Wixels are based on TI's versatile CC2511F32, so they are not inherently restricted to working in pairs. Most of the apps we have available now are designed to be used with pairs of Wixels, but we have some apps (e.g. the I/O Repeater) that allow for many-to-many communications, and you can write your own apps to allow for communication among a network of Wixels, too.

The Wixel is similar to the XBees in many ways, but with the integrated USB, programmable microcontroller, and 0.1" pin spacing, we feel they are a compelling, lower-cost alternative for many wireless projects (and as far as I know, wireless Arduino programming cannot be easily done with XBees).

  • Ben

sounds good
so for simple two-way Arduino-Arduino communication a pair of wixels sounds like a neat solution!

will the shield + 2 wixels deal be available in the UK?
I can only see it on the Pololu site and postage doubles the price :frowning:

Oh, I'm sorry I forgot to answer that part of your last post! Whether it becomes available in the UK is up to our UK distributors. We don't have a very good way of tracking which products our various distributors stock, but you can check with them directly:

Because the Wixel shield is so new, I don't think any of them carry it yet, but they might be willing to start if you contact them and request it.

  • Ben

another wixel question...

If I run a UNO at 3 volts (2 AA) am I right in thinking I don't need the step up/down level shifters?
hence I can directly wire from UNO D0/D1 to Wixel TX/RX?

thanks

If you are interfacing the Wixel with a part running at the same voltage, you don't need shifters. However, I was under the impression the minimum recommended operating voltage for the Arduino Uno is 7 V. Furthermore, according to the datasheet, an ATmega328 running at 16 MHz requires at least 4.5 V to be in spec (you can run it at lower voltages if you keep the clock at 8 MHz or less). Separately, I think you'd be better off boosting a single AA battery to 3.3 V with a regulator or using two cells with a sepic or buck-boost regulator than powering your circuits directly from two AA cells.

  • Ben

the limits they mention apply if you're using the on-board regulator(s)
you can just feed 5 volts regulated directly into Vin

looks like I may be going the higher voltage route after all :slight_smile:

I want to keep running at 16 MHz, hadn't spotted that part!

I have heard of people running their AVRs above 8 MHz while supplying under 4.5 V without noticing any problems, though they are technically out of spec and who knows what sorts of weird bugs could appear at inopportune moments!

  • Ben

mmcp42:
the limits they mention apply if you're using the on-board regulator(s)
you can just feed 5 volts regulated directly into Vin

Wrong, Vin just feeds to the INPUT of the on-board 5vdc regulator. You can of course feed a regulated +5vdc to the shield +5vdc pin.

looks like I may be going the higher voltage route after all :slight_smile:

I want to keep running at 16 MHz, hadn't spotted that part!

oops
that is in fact what I meant
it was ok when it left my brain
got distorted once it reached the fingers!

thanks!

Back on topic, I finally got my seeeduino project taking to the IDE using a pair of wixels.
I followed the user guide (shock horror) and downloaded wireless app 1.3 shield version.
I did have to change the default baud rate to 57600

I also found that a steady red LED seems to keen low voltage AKA time to change the batteries

Onwards and upwards!

Mike

Onwards and upwards!

That is so cool. I have been very tempted to buy a pair of Wixel. The ability to easily change from a IDE to arduino board so that one can upload new sketches wirelessly, or to reconfigure them as a simple arduino to arduino wireless link is sure attractive. I just wish the range was a bit more then 50ft, however maybe they are rating that conservatively?

Lefty

@ lefty,

buy two pair of wixels and maybe you can build yourself some repeaters ... ?

retrolefty:
I just wish the range was a bit more then 50ft, however maybe they are rating that conservatively?

It's hard to give an exact range because it is affected by a number of variables, including intermediate objects, Wixel orientation (a Wixel sitting flush against a surface might have a slightly different range than if it is a few inches above that surface), and even unit-to-unit variation. The 50-foot range is meant to be a rough estimate of the range at which a reasonable data rate is still achievable in a typical (somewhat RF-noisy) indoor environment, where the Wixels several rooms apart with a few walls between them. We tried a pair outside with direct line of sight and were able to achieve good wireless serial communication out to approximately 200 feet, but I don't have any sense for how much this line-of-sight range might vary from unit to unit, so please don't treat this as an official spec.

  • Ben

my work station (ok the place where I spent all day slumped over the lap-dancer) is electrically very noisy
laptop
wireless mouse
fast wireless router
bluetooth printer
couple of mobile phones
land line (wireless of course)

my new shiny project works fine with the tethered end in the middle of the mess described above and the "works" in the next room (through a brick wall into another room with mobiles and wirleess handsets)
only 10' or so (ok I couldn't b *rsed to walk any further), but noisy as hell
so two thumbs up from me

Hi Bens,

I need your help now.

I have an RF device pair to control on/off a lamp. The transmitter and receiver are used CC2500 chip (I saw CC2500 chip after removing box). And now I want to replicate the transmitter for a spare. The RF devices have no any technical document.

So what should I do to replicate the transmitter?

Thank so much.

Regards,