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I am currently looking in various Arduino.

I'd like to build a very specific device:

I'd like to have a lamp (using a RGB LED (already have one)) that can change the color (or do custom routines like blinking etc...).

But these specifications must be met:

  • Battery powered (so all items must use minimum power)
  • WiFi enabled

It's sufficient if I can change the color (or trigger a routine) from a computer on the same network (via netcat or curl).

I looked in the WiFly shield. Is there another shield which is maybe better? What main Arduino main board is best for my purpose?

Update:

As there are some follow up questions:

  • The Arduino is not a must. I thought it would be the easiest solution. The raspberry pi didn't come to mind, but is an excellent suggestion. However I'm not sure if it is that easy to hook an LED on to it, also I'm not sure about the Power supply (given that I would be using an USB Wifi Dongle).
  • I didn't think that the power supply would that big of a deal as the LED would rarely been switched on (once every few days). Is the idling in the WiFi so power intense?
  • For the background of what I'm trying to build: I want to build an extreme feedback device (a device to indicate the status of the automated tests in a software project) to carry around.
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    \$\begingroup\$ Note that this is a fairly expensive way to solve the problem as it uses parts and assemblies which do not enjoy the economies of scale in more common consumer wifi products such as a surplus android phone, a wifi router known to be hackable, or potentially something like a RasberryPi with a USB wifi dongle. \$\endgroup\$
    – Chris Stratton
    Commented Jan 5, 2012 at 16:01

3 Answers 3

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Based off of your two specifications of

Battery powered (so all items must use minimum power)

WiFi enabled

I would recommend not going with an Arduino at all as it will be much more difficult to meet the minimum power requirement. In order to minimize your power you will need to look into spinning your own board with a very low power microcontroller. It seems like almost every microcontroller company sells some version of ultra low power, but the MSP430 seems to be the most widely used line for low power.

As far as the WiFi enabled part, this is a little bit more difficult to get to be low powered. If you are fine with having your device waking up to check in to see what it needs to do with the LED then you can get your power even lower. However, my guess is that you are actually wanting to be able to send your device a packet at any time to tell it to do something with the LED. In order to go this path with lowest power you would be best rolling your own WiFi solution, but my guess also is that you do not care to do this. So you will want to look for a module that will do this for you. Roving Networks has a few options that support 4uA sleep mode and 38mA active.

With all of that said, if you still want to go with an Arduino (even though you didn't say it was a requirement) you will have to settle for very poor battery life. By very poor battery life I mean something less then a day unless you want to lug around a car battery.

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  • \$\begingroup\$ It looks like the wifly shield can generate an interrupt, so the processor should be able to sleep making the difference between the Arduino's ATMEGA and something else comparatively unimportant. The real power hog would be the wifi component's radio and onboard processor which handles the network protocols, so trying to identify the lowest power solution there would be important - though it's likely to depend on traffic. \$\endgroup\$
    – Chris Stratton
    Commented Jan 5, 2012 at 16:06
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    \$\begingroup\$ I don't have a problem with using the ATMEGA, but the Ardunio itself is not exactly designed for lower power consumption, things like using a linear voltage regulator, power LED, etc. And the difficulties with the wifi module will exist both with and without using an Ardunio, so might as well cut any of the extra power draw that you easily can. Unless someone has made an ultra low power Ardunio? \$\endgroup\$
    – Kellenjb
    Commented Jan 5, 2012 at 16:10
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There are some really nice (and $6 cheap) Bluetooth UART modules which might be a much cheaper alternative if you are more interested in being wireless, than specifically using Wi-Fi. I use these (http://www.ebay.com/itm/190433073764) with Arduino and they are very easy to get fired up. As Cornbread Ninja suggests, Xbee was practically invented for your exact need, but it's still more expensive than the BT option.

It's also true that there arn't going to be any really low power solutions for you which ever way you go, unless you are really keen on going off piste with some exotic uCs, but I'm guessing if your original plan was an Arduino and Wifly, or a rPi and a wifi dongle, this isn't a huge issue for you.

finally, check out the electric Imp too, that could be an option. http://electricimp.com/

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The Arduino Uno should meet your needs. You might want to look into the xbee shield.

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    \$\begingroup\$ I don't think Xbee can do WiFi. \$\endgroup\$
    – Kellenjb
    Commented Jan 5, 2012 at 15:49
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    \$\begingroup\$ @Kellenjb - that's true. However, while not argued in this answer, it's worth considering if one might come out ahead on battery life and cost by using a wireless standard more suited to that, even after having to buy a transceiver for the PC (or whatever) end of the link. \$\endgroup\$
    – Chris Stratton
    Commented Jan 6, 2012 at 13:27
  • \$\begingroup\$ digi.com/products/wireless-wired-embedded-solutions/… \$\endgroup\$
    – cornbread ninja
    Commented Jan 6, 2012 at 15:24

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