# Bidirectional communication with BlueTooth

**URL:** <https://community.sparkfun.com/t/bidirectional-communication-with-bluetooth/11625>\
**Category:** Wireless & IoT\
**Created:** [June 21, 2009, 8:33pm UTC](https://community.sparkfun.com/t/bidirectional-communication-with-bluetooth/11625 "2009-06-21T20:33:49Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![Sparkles](https://avatars.discourse-cdn.com/v4/letter/s/ed8c4c/32.png) [@Sparkles](https://community.sparkfun.com/u/Sparkles)\
**Post date:** [June 21, 2009, 8:33pm UTC](https://community.sparkfun.com/t/bidirectional-communication-with-bluetooth/11625/1 "2009-06-21T20:33:49Z")

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I’ve seen this module:

[http://www.sparkfun.com/commerce/produc … cts\_id=582](http://www.sparkfun.com/commerce/product_info.php?products_id=582)

Is it possible to accomplish bidirectional communications using two of these modules? So as well send and receive data at the same time?

Thanks in advance.

Sparkles

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**Author:** ![Sparkles](https://avatars.discourse-cdn.com/v4/letter/s/ed8c4c/32.png) [@Sparkles](https://community.sparkfun.com/u/Sparkles)\
**Post date:** [June 22, 2009, 7:35pm UTC](https://community.sparkfun.com/t/bidirectional-communication-with-bluetooth/11625/2 "2009-06-22T19:35:51Z")

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Anyone?

I just want to be able to do bidirectional communication wireless over approx. 30 m.

I don’t know if bluetooth is a good solution or if there are other possibilities?

Thanks in advance.

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**Author:** ![phishguy](https://avatars.discourse-cdn.com/v4/letter/p/df705f/32.png) [@phishguy](https://community.sparkfun.com/u/phishguy)\
**Post date:** [June 22, 2009, 7:45pm UTC](https://community.sparkfun.com/t/bidirectional-communication-with-bluetooth/11625/3 "2009-06-22T19:45:11Z")

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Yes, those modules will do what you want.

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**Author:** ![JoeStrout](https://avatars.discourse-cdn.com/v4/letter/j/71e660/32.png) [@JoeStrout](https://community.sparkfun.com/u/JoeStrout)\
**Post date:** [June 22, 2009, 11:08pm UTC](https://community.sparkfun.com/t/bidirectional-communication-with-bluetooth/11625/4 "2009-06-22T23:08:17Z")

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> phishguy:  
> Yes, those modules will do what you want.

How do they do that, exactly? My understanding is that BT is a master/slave system, and that the BT serial modules (BlueSMIRF for example) are slave-only. How do you set up a peer-to-peer network with them?

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**Author:** ![phishguy](https://avatars.discourse-cdn.com/v4/letter/p/df705f/32.png) [@phishguy](https://community.sparkfun.com/u/phishguy)\
**Post date:** [June 23, 2009, 12:58am UTC](https://community.sparkfun.com/t/bidirectional-communication-with-bluetooth/11625/5 "2009-06-23T00:58:49Z")

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Bluesmirf and just about any other Bluetooth modules can be configured as master or slave. So, you configure one as master, the other as slave, pair them up, and then you have a bi-directional wireless serial port connection.

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**Author:** ![Sparkles](https://avatars.discourse-cdn.com/v4/letter/s/ed8c4c/32.png) [@Sparkles](https://community.sparkfun.com/u/Sparkles)\
**Post date:** [June 23, 2009, 7:43pm UTC](https://community.sparkfun.com/t/bidirectional-communication-with-bluetooth/11625/6 "2009-06-23T19:43:33Z")

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What do you exactly mean with pair them up? I really want to know if bidirectional communication is possible.

I’ve first wanted to try the nrf24l01+ to accomplish the same effect. First I’ve heard that bidirectional communication is no problem with these modules, but after further literature study I’ve noticed this is not possible.

These Bluetooth modules are quite expensive (compared to the nrf24L01) so therefore I want to know if it works 🙂

Anyone with other ideas?

Thanks in advance.

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**Author:** ![phishguy](https://avatars.discourse-cdn.com/v4/letter/p/df705f/32.png) [@phishguy](https://community.sparkfun.com/u/phishguy)\
**Post date:** [June 23, 2009, 8:25pm UTC](https://community.sparkfun.com/t/bidirectional-communication-with-bluetooth/11625/7 "2009-06-23T20:25:57Z")

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As I said, yes it will work bidirectionally for RS232 data. Error correction is handled within the Bluetooth SPP stack. Once the modules are configured properly, they will appear almost the same as a hardware connection. The only worries you might have is if you are using high data rates you might need to use handshaking and there is a small amount of data lag. I would recommend reading the documentation for the RN41 Bluetooth module to see it’s capabilities in order to figure out if it will fit your application.

Pairing is where a master device will look for the specific Bluetooth hardware address of a slave device and connect to that device.

BTW, if you’re going to incorporate Bluetooth onto a PCB, I recommend using the RN41 module. They aren’t too terribly expensive and I have had very good results with these modules. They can be purchased from many sources such as Mouser or Digikey.
