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I can control a relay from an Android smartphone using Arduino and Bluetooth as seen here.

However, it seems too costly to be using Arduino and a Bluetooth receiver for driving a switch. As long as Bluetooth is a radio frequency, is it possible to make a simple Bluetooth receiver which can output 1 or 0 to drive a relay? If yes, how tough that is going to be?

The main factor here is the cost, which should be \$1-$5.

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    $\begingroup$ This is not a good question for the robotics SE. The reason being 1) it's not really specific to robotics, rather it's about using bluetooth. 2) it's not well posed, and doesn't show a lot of research. "Since bluetooth is a radio frequency" doesn't make a lot of sense. Bluetooth is a communications protocol (like TCP), which is made to be transmitted over specific radio frequencies. Is your question about the BT protocol, driving a relay, or an arduino solution? $\endgroup$ – Josh Vander Hook Dec 10 '12 at 21:36
  • $\begingroup$ Your question seems focused on bluetooth specifically, but it sounds like you're really asking for a cheap way to wirelessly control a relay. Is that accurate? $\endgroup$ – Ian Dec 11 '12 at 1:43
  • $\begingroup$ Yes that's right I didn't do much research, I was just checking the possibilities and feasibility. Yes I am asking for a cheap way to wirelessly control a relay via bluetooth. $\endgroup$ – ruben Dec 11 '12 at 4:33
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I'm in agreement with @movrev but wanted to expand beyond the scope of a comment. RN-42 is slick. I'm coding for it now, and I think it is an excellent BT choice.

Low cost and multiple receivers (switches) appear to be mutually exclusive. You might consider the RN-42 as a BT receiver to preserve smartphone interface. Then, you might consider an 802.15 (Zigbee) mesh-like solution to distribute a switch command from the RN-42 "master" receiver to the "slave" switches. The Microchip MRF24J40 is a reasonable 802.15 solution.

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The question is a bit vague, but I would say that you at least need to spend ~$16 in a Bluetooth receiver. I have experience with roving networks modules, such as the RN42, which are easy to set up as wireless serial ports (you can talk to them via pyserial or the like).

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  • $\begingroup$ I saw this RN42 but I am not going to do extensive work using bluetooth like large amount of data transfer etc. Suppose I need to control 10 switches in different locations, for that if I need to use 10 RN42 devices that isn't feasible. I need to do it using a less costly bluetooth receiver (custom made?) $\endgroup$ – ruben Dec 11 '12 at 4:42
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    $\begingroup$ I don't think that this is a realistic scenario. For a chip to be certified Bluetooth, it has to support the whole communications stack, which is what drives the complexity and the cost up. Assuming you do find an inexpensive Bluetooth chip to do your biding, you'll then realize that these have fairly large power consumption and you'll have to start thinking about custom boards with 802.15.4/ZigBee modules. $\endgroup$ – fgb Dec 11 '12 at 7:27

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