alexellis
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Location: United Kingdom
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Wireless sensors.. Serial over BT/WIFI or other RF?

Thu Jan 08, 2015 12:31 am

I have seen a few topics with suggestions for wireless sensing - using a RF connection to let several cheap and cheerful Arduinos send data back to a Raspberry PI, but these posts are embroiled with lengthy requirements - or half solutions.

I wondered - what is the easiest and cheapest way to let i.e. a door sensor/ PIR and temp sensor all connected to individual Arduino Nanos/Minis post data back to a master Raspberry PI? I have seen some code working with the HC-05 on the Arduino end - and this looks straight forward, but what about the PI - in Python for instance?

I have seen the 433mhz modules - but it looks like these use manchester encoding, which could be CPU intensive and hard to get started with. ESP8266 is listed and also HC-05 as a Wifi and Bluetooth serial link. Has anyone used either of these modules, can you help?

Thanks in advance,

Alex Ellis

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iinnovations
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Joined: Thu Jun 06, 2013 5:17 pm

Re: Wireless sensors.. Serial over BT/WIFI or other RF?

Thu Jan 08, 2015 12:45 am

Moteino: http://lowpowerlab.com/blog/2012/12/20/ ... ino-clone/

Cheap atmega328p (Uno) clone with Hope RF modules. Mature code-base, actively developed, good forum and great support.

I've done a few things with them:
http://www.cupidcontrols.com/2014/02/mo ... id-remote/
http://www.cupidcontrols.com/2014/10/cu ... e-io-mote/
http://www.cupidcontrols.com/2014/11/cu ... ontroller/

Colin
CuPID Controls :: Open Source browser-based sensor and device control
interfaceinnovations.org/cupidcontrols.html
cupidcontrols.com

alexellis
Posts: 53
Joined: Tue Nov 26, 2013 10:00 am
Location: United Kingdom
Contact: Website

Re: Wireless sensors.. Serial over BT/WIFI or other RF?

Fri Jan 09, 2015 5:28 pm

This is 433mhz technology.

Has anyone in the forum used a Serial or BT link module?

rgrbic
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Re: Wireless sensors.. Serial over BT/WIFI or other RF?

Fri Jan 09, 2015 5:35 pm

I used nrf24l01 modules. Here is text about it.
At 127.0.0.1
Twitter: @rgrbic
IoT-projects.com

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Douglas6
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Re: Wireless sensors.. Serial over BT/WIFI or other RF?

Fri Jan 09, 2015 6:45 pm

I've played around with a couple of HC-05 modules for Arduino to Pi communication, and they're relatively easy to use, as they appear as serial ports on both ends. And they're cheap. On the Pi, you can either wire up a module, or use a Bluetooth dongle. The pyserial library makes coding in Python easy. But, there may be an issue if you want the Pi talking to multiple modules. I believe you'll have to connect to one at a time, which takes some seconds (up to 20.) Classic Bluetooth was intended as a cable replacement, so it's best suited for long term, point-to-point connections.

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iinnovations
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Re: Wireless sensors.. Serial over BT/WIFI or other RF?

Fri Jan 09, 2015 8:03 pm

alexellis wrote:This is 433mhz technology.

Has anyone in the forum used a Serial or BT link module?
They offer many frequencies. They have ATmega328P attached, so they talk over serial and function as Arduino Uno with any normal IDE. The libraries are well-developed, supported, and active.

Is there a reason you are stuck on bluetooth? Do you have an existing device you wish to make compatible?
CuPID Controls :: Open Source browser-based sensor and device control
interfaceinnovations.org/cupidcontrols.html
cupidcontrols.com

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